PVC Termination Time: A Novel Real-Time Predictor of Ablation Success

PVC Termination Time: A Novel Real-Time Predictor of Ablation Success | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article PVC Termination Time: A Novel Real-Time Predictor of Ablation Success Keijiro Nakamura, Naohiko Sahara, Jumpei Yamamoto, Takayuki Shimizu, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7698543/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 09 Dec, 2025 Read the published version in Journal of Interventional Cardiac Electrophysiology → Version 1 posted You are reading this latest preprint version Abstract Background: During PVC ablation, operators need real-time feedback to optimize outcomes. We hypothesized that PVC Termination Time (PTT)—the interval from radiofrequency onset to PVC disappearance—would outperform local activation time (LAT) in predicting acute success. Objectives: To evaluate the predictive value of PTT compared with LAT in PVC ablation. Methods: We analyzed 310 applications in 54 patients undergoing PVC ablation. PTT and LAT were measured for each application. Acute success was defined as elimination of PVCs without recurrence within 30 minutes. ROC and logistic regression analyses were performed, with location-specific analyses and long-term follow-up. Results: Acute success was achieved in 50/54 patients (92.6%). PTT was significantly shorter in successful versus failed applications (median 12s [IQR 8–18] vs 62s [IQR 45–75], p<0.0001). LAT was earlier in successful applications (–36 ms vs –26.5 ms, p<0.01). PTT showed superior predictive accuracy (AUC=0.93) versus LAT (AUC=0.72). A PTT cutoff of 25s yielded 88% sensitivity and 83% specificity. Location-specific analysis showed variability, especially in LV summit cases. In multivariable analysis, both shorter PTT (p<0.001) and earlier LAT (p=0.005) predicted success. Long-term follow-up (18±6 months, n=48) demonstrated 85.4% freedom from recurrence; recurrent cases had longer PTT during index ablation (28.5s vs 11.5s, p=0.008). Conclusions: PTT is a practical, real-time predictor of acute PVC ablation success, outperforming LAT. A 25-second cutoff provides objective procedural guidance, though anatomical variations should be considered. CONDENSED ABSTRACT We evaluated PVC Termination Time (PTT)—the interval from radiofrequency onset to PVC disappearance—as a predictor of ablation success in 54 patients (310 applications). PTT was significantly shorter in successful versus failed applications (median 12s vs 62s, p<0.0001) and demonstrated superior predictive accuracy (AUC=0.93) compared to local activation time (AUC=0.72). A 25-second PTT cutoff provided 88% sensitivity and 83% specificity. Location-specific PTT showed variations, with LV summit demonstrating wider variability (IQR 5-38s). PTT offers a practical, real-time metric for guiding PVC ablation procedures, potentially improving efficiency and outcomes. premature ventricular contractions catheter ablation PVC termination time LAT real-time ablation marker Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Catheter ablation has emerged as an effective treatment strategy for symptomatic premature ventricular contractions (PVCs), with success rates typically exceeding 80% for most PVC subtypes ( 1 , 2 ). Accurate identification and effective elimination of the arrhythmogenic focus remain essential determinants of procedural success. Conventionally, local activation time (LAT) has served as the primary mapping parameter for targeting ablation sites, with earlier (more negative) LAT values generally indicating closer proximity to the site of origin ( 3 , 4 ). While LAT-guided mapping has demonstrated clinical utility, it provides only static information about the target site and fails to capture the dynamic tissue-catheter interaction during energy delivery. Previous investigations have established that LAT values earlier than − 30 ms are associated with favorable outcomes ( 5 ), but LAT alone cannot assess the quality of lesion formation or the arrhythmogenic substrate's responsiveness to ablation energy. In everyday clinical practice, electrophysiologists frequently observe that the rapidity with which PVCs are eliminated after radiofrequency (RF) energy initiation may be more predictive of procedural success than pre-ablation mapping parameters. However, this temporal relationship between ablation initiation and PVC elimination has not been systematically evaluated as a predictive metric in the literature. We hypothesized that the interval from ablation onset to PVC elimination, which we have termed "PVC Termination Time (PTT)," represents a more direct and physiologically relevant predictor of successful ablation. This pilot study aimed to: ( 1 ) evaluate the predictive power of PTT compared to conventional LAT, ( 2 ) determine the optimal PTT threshold for procedural success, ( 3 ) assess location-specific PTT variations, and ( 4 ) examine the incremental value of combining PTT with LAT for enhanced intra-procedural decision-making. Methods Study Population We performed an analysis of 310 ablation applications conducted in 54 consecutive PVC patients (mean age 58 ± 12 years, 62% male) at a multi-center institute between January 2022 and December 2024. Inclusion criteria encompassed adult patients (≥ 18 years) undergoing catheter ablation for symptomatic, high-frequency, and/or drug-refractory PVCs. We prospectively collected clinical data, electrocardiogram (ECG), and intracardiac electrogram data. All patients underwent comprehensive evaluation including 12-lead ECG, 24-hour Holter monitoring, and transthoracic echocardiography. PVC burden was quantified as the percentage of PVCs relative to total heartbeats during 24-hour monitoring ( 2 ). Anti-arrhythmic medications were discontinued for at least five half-lives before the procedure. Patients without spontaneous PVCs before the procedure were excluded. Patients with structural heart disease (previous myocardial infarction, cardiomyopathy with LVEF < 40%, congenital heart disease, or cardiac sarcoidosis) were also excluded. Only patients with monomorphic PVCs of local origin based on ECG and electrophysiological criteria were included. The study protocol was approved by our institutional review board (H22006), and all patients provided written informed consent. Electrophysiological Study and Ablation Procedure All procedures were performed without sedation or general anesthesia to preserve spontaneous PVC frequency; however, local anesthesia at vascular access sites and minimal sedation were administered as needed for patient comfort. Vascular access was obtained via the femoral vein and/or artery based on suspected PVC origin. A quadripolar catheter was positioned in the right ventricular apex for timing reference. Activation mapping was performed using the EnSite NavX system (Abbott, Chicago, IL) with an HD Grid high-density electrode catheter during spontaneous PVCs ( 6 , 7 ). LAT was measured as the interval between the earliest deflection of the local bipolar electrogram and the onset of the surface QRS complex during PVCs, with negative values indicating pre-systolic activation. Unipolar electrograms were analyzed for QS morphology at each target site. All potential ablation sites including RVOT, LVOT, aortic cusps, and epicardial sites were systematically evaluated before ablation. LAT measurements were reviewed by two experienced electrophysiologists with discrepancies resolved by consensus. Pace mapping was performed at potential target sites using minimum output for myocardial capture (typically 2 mA above threshold) with 2.0 ms pulse width. A pace mapping score was calculated based on matching leads between paced QRS morphology and clinical PVC (12/12 indicating perfect match). Intracardiac electrogram characteristics suggesting PVC origin included sharp presystolic potentials, high-frequency components, and fractionated signals. For infrequent PVCs, programmed ventricular stimulation and/or isoproterenol infusion (1–5 µg/min) was used for induction. Radiofrequency energy was delivered at target sites identified through activation mapping, pace mapping, and electrogram analysis. Target sites were selected based on earliest activation with LAT ≥ 20 ms pre-QRS, pace mapping score ≥ 11/12, and/or characteristic electrogram patterns. RF energy was delivered using a TactiFlex SE ablation catheter (Abbott), a 3.5-mm irrigated-tip catheter with contact force sensing. Power settings were 30–40 W for endocardial sites and 20–30 W for high impedance sites. Maximum temperature was limited to 43°C with irrigation flow rates of 17–30 mL/min. RF was applied for up to 60–120 seconds at each target site. PTT was prospectively recorded for each ablation attempt, defined as the interval from RF initiation to complete elimination of the targeted PVC, measured in seconds. Complete elimination was defined as the last observed PVC of that morphology, after which no further PVCs occurred during remaining RF application. If PVCs persisted beyond 60 seconds, the catheter was repositioned and those applications were classified as unsuccessful. Definition of Outcomes Acute procedural success was defined as complete elimination of the targeted PVC during the procedure with no recurrence during 30-minute observation including programmed stimulation and isoproterenol infusion. Long-term success was defined as absence of the targeted PVC on 12-lead ECG and 24-hour Holter at follow-up visits, with PVC burden < 5%. Statistical Analysis Statistical analyses were performed using R version 4.0.3. Continuous variables were expressed as median [interquartile range] for non-normally distributed data; categorical variables as counts and percentages. Comparisons between groups used Mann-Whitney U test for continuous variables and chi-square test for categorical variables. Receiver operating characteristic (ROC) analysis evaluated the predictive performance of LAT and PTT, with optimal cutoff values determined using the Youden index. Logistic regression models assessed the independent contribution of each parameter to procedural success. Mixed-effects logistic regression with patient-specific random intercepts accounted for multiple applications per patient. The intraclass correlation coefficient (ICC) was calculated to assess within-patient correlation. ROC confidence intervals were calculated using cluster bootstrap resampling (1000 iterations). A sensitivity analysis using only the first ablation application per patient was conducted. A two-dimensional risk surface was generated to visualize the relationship between LAT, PTT, and probability of success. Statistical significance was defined as p < 0.05. Results Baseline Characteristics and Acute Success Rate Among 54 patients, the mean pre-procedural PVC burden was 22 ± 11% of total heartbeats. Acute PVC elimination was achieved in 50 patients (92.6%). Successful ablation sites were most commonly in the right ventricular outflow tract (46%), followed by the left ventricular outflow tract and adjacent structures (30%), LV summit (15%), other RV locations (4%), and other LV locations (5%) (Table 1). Predictive Value of PTT versus LAT Across 54 successful ablation applications (one per successful patient), median PTT was 12 seconds [IQR 8–18], range 2–59 seconds. LAT values showed median − 36 ms [IQR − 42 to -28], range − 55 to 0 ms. In successful applications, PTT showed an inverse relationship with LAT: earlier LAT values were associated with shorter PTT (r = -0.45, p < 0.001). Comparing successful versus failed applications across all 310 attempts, median PTT in successful applications was significantly shorter than in failed applications (12s [IQR 8–18] vs 62s [IQR 45–75], p < 0.0001; Fig. 2 ). Similarly, LAT was significantly earlier in successful applications (median − 36ms [IQR − 42 to -28] vs -26.5ms [IQR − 32 to -18], p < 0.01; Fig. 3 ). ROC analysis confirmed both parameters as significant predictors of procedural success, but PTT demonstrated superior discriminative ability (AUC = 0.933, 95% CI 0.889–0.969) compared to LAT (AUC = 0.719, 95% CI 0.640–0.792). The optimal PTT cutoff was 25 seconds, yielding 88.4% sensitivity and 83.2% specificity for acute success. For LAT, the optimal cutoff was − 30 ms (sensitivity 72.1%, specificity 68.4%). The combined PTT + LAT model did not significantly improve the AUC over PTT alone (AUC = 0.934 vs 0.933, p = 0.78). Location-Specific PTT Analysis PTT showed trends toward variation by anatomical location, though statistical comparison was limited by small sample sizes in several groups (LVOT n = 4, LV other n = 3). RVOT origins demonstrated median PTT of 12s [5–20], LVOT 7s [6–11], and LV summit 13s [5–38] with notably wider IQR (Table 3). The wide IQR in LV summit cases is consistent with the known challenges of this location described by Garg et al. ( 8 ). Multivariable and Mixed-Effects Analysis In multivariate logistic regression, both PTT and LAT were independent predictors of success (shorter PTT: β=-0.090 ± 0.013, p < 0.001; more negative LAT: β=-0.064 ± 0.023, p = 0.005). Mixed-effects modeling accounting for patient-level clustering confirmed PTT remained a strong predictor (p < 0.001) while LAT did not remain significant (p = 0.089). The ICC was 0.0004, indicating negligible within-patient correlation between applications, likely due to high variability in catheter position and contact between attempts. Sensitivity analysis using only first ablation per patient showed PTT was significant (p = 0.0012) but LAT was not (p = 0.352). Two-Dimensional Risk Analysis A two-dimensional risk surface plot illustrating the relationship between LAT, PTT, and probability of success showed highest predicted success probabilities (> 90%) when LAT was earlier than − 30 ms and PTT was shorter than 20 seconds (Fig. 5 ). Conversely, lowest predicted success probabilities (< 10%) were seen when LAT was later than − 20 ms and PTT exceeded 40 seconds. This analysis suggested a continuous gradient of success probability rather than sharp binary threshold. Additional Electrophysiological Parameters Peak frequency at ablation sites and ΔLAT (difference between first deflection and near-field signal timing) showed no significant association with acute procedural success (p = 0.32 and p = 0.47, respectively). Long-Term Follow-Up Outcomes Long-term follow-up (mean 18 ± 6 months) was available in 48 of 50 patients with acute success. Overall long-term success rate was 85.4% (41/48). Patients remaining free of PVC recurrence had significantly shorter median PTT during index procedure than those with recurrence (11.5s [IQR 8–15] vs 28.5s [IQR 20–38], p = 0.008), while LAT values were similar (median − 35ms [IQR − 40 to -28] vs -33ms [IQR − 38 to -25], p = 0.42). Notably, among the 7 patients with recurrence, 5 had PTT > 25 seconds during the index procedure, suggesting that prolonged PTT may indicate either intramural origin or inadequate lesion formation. Two patients with very short PTT (< 10 seconds) but late recurrence may represent cases of multiple exit sites or incomplete elimination of the arrhythmogenic substrate. Discussion This study introduces and validates PVC Termination Time as a novel real-time indicator of acute ablation success. PTT demonstrated superior predictive power compared to conventional LAT mapping, with a practical threshold of 25 seconds serving as an objective intra-procedural guide. Our findings provide important insights into the dynamic aspects of PVC ablation that complement traditional static mapping parameters. Mechanistic Insights and Pathophysiological Implications PTT captures dynamic procedural information that LAT alone cannot provide. While LAT reflects the spatial relationship between the catheter and the arrhythmogenic focus ( 3 , 4 ), PTT incorporates multiple factors including tissue response to ablation energy, catheter contact quality, tissue characteristics, and lesion formation efficiency—factors not captured by pre-ablation mapping. These observations align with previous studies by Latchamsetty et al. ( 2 ) and Choi et al. ( 6 ) highlighting limitations of pre-procedural mapping parameters in predicting ablation success. A short PTT likely indicates several favorable conditions: excellent catheter-tissue contact, superficial PVC origin allowing rapid transmural lesion formation, and absence of protective tissue barriers such as epicardial fat or intramural scar. Conversely, prolonged PTT might indicate deeper intramural focus, suboptimal catheter contact, presence of epicardial fat as described by Bazan et al. ( 9 ) and Sosa et al. ( 10 ), or proximity to high-flow vascular structures causing heat sink effect. When the catheter tip is well apposed to tissue with minimal movement, energy delivery is more efficient and lesion formation more rapid, supporting the use of PTT as a surrogate for lesion quality in real time. The inverse relationship between LAT and PTT in successful cases suggests that when the catheter is truly at the site of origin (earliest LAT), less time is required for effective ablation. This aligns with the fundamental electrophysiological principles established by Nakagawa et al. ( 11 ) for Purkinje-related arrhythmias and extends to PVC ablation. However, we observed outliers where successful ablation occurred despite prolonged PTT (> 25s) with only moderately early LAT values. These cases likely represent scenarios where mapping was challenging due to infrequent PVCs, unstable catheter positioning in difficult locations like aortic cusps as described by Ouyang et al. ( 12 ), or intramural origin requiring sustained energy delivery. Location-Specific Considerations Our location-specific analysis revealed important PTT variations that have direct clinical implications. RVOT origins showed the shortest PTT (median 10s), consistent with the relatively thin myocardial wall and accessibility of this region. This finding corroborates previous work by Azegami et al. ( 4 ) demonstrating the favorable anatomical characteristics of RVOT for ablation. LVOT origins required slightly longer ablation times (median 14s), possibly reflecting thicker myocardium or proximity to coronary vasculature requiring more cautious energy delivery, as noted by Yamada et al. ( 5 ) in their analysis of preferential conduction patterns. Most notably, LV summit origins showed median PTT of 13s with notably wider variability (IQR 5-38s), suggesting heterogeneous tissue characteristics in this region. While the median value was similar to other locations, the broad IQR indicates that some LV summit cases may require extended ablation times. This finding aligns with recent work by Watanabe et al. ( 13 ) who reported arrhythmia elimination times of approximately 12 ± 12s for successful endocardial ablations versus 32 ± 24s for epicardial approaches in LV summit PVCs. Furthermore, Garg et al. ( 8 ) demonstrated that prolonged duration ablation from endocardial locations can be a successful strategy for LV summit PVCs, supporting our observation that longer PTT may be acceptable or even necessary for certain anatomical locations. These location-specific variations suggest that while a general 25-second threshold provides useful guidance, operators should consider anatomical context when interpreting PTT. For suspected intramural origins or cases with wide PTT variability such as observed in our LV summit cohort, operators should consider individual tissue characteristics rather than applying rigid time thresholds, whereas for typical RVOT origins, failure to eliminate PVCs within 15–20 seconds should prompt repositioning. This approach is consistent with the site-specific strategies advocated by Hutchinson and Garcia ( 14 ) in their comprehensive review of outflow tract arrhythmia management. Clinical and Procedural Implications The identification of 25 seconds as an optimal PTT cutoff has important practical implications. In our study, PVCs in successful ablations were often eliminated well before 25 seconds (median 12 seconds). Our 2D risk analysis indicated that PTT ≤ 20 seconds combined with LAT more negative than − 30 ms yielded > 90% predicted success. Thus, while 25 seconds is statistically optimal, an even shorter PTT could be used as a stricter intra-procedural gauge. This threshold enables objective decision-making during procedures, similar to the V2 transition ratio described by Betensky et al. ( 15 ) for differentiating PVC origins. If PVCs persist beyond 25 seconds of RF delivery at typical endocardial sites, the probability of success at that site falls dramatically, suggesting further energy delivery may yield diminishing returns. This approach could expedite decision-making, potentially reducing unnecessary lesion delivery, procedure time, and complications. For complex cases such as suspected intramural PVCs or unusual locations like the pulmonary artery described by Sekiguchi et al. ( 16 ) or the mitral annulus reported by Tada et al. ( 17 ), incorporating PTT provides immediate feedback about whether the current strategy is effective. Similarly, for epicardial sites accessed via the technique described by Sosa et al. ( 10 ), PTT may help determine when to pursue alternative approaches. Comparison with Contemporary Literature Our findings complement recent advances in PVC ablation strategy. Sabzwari et al. ( 18 ) found that large differences between bipolar and unipolar activation times (ΔLATBi-Uni ≥ 15 ms) predicted the need for bi-ventricular ablation for outflow tract PVCs, conceptually paralleling our finding that PTT > 25s suggests a potentially intramural focus requiring more extensive ablation. Im et al. ( 7 ) identified factors like female sex, single PVC morphology, and very early bipolar activation (> 24 ms pre-QRS) as predictors of durable success in their Europace study. While these factors relate to baseline patient and PVC characteristics, PTT provides immediate procedural feedback that can guide real-time decision-making. The combination of favorable baseline factors and rapid PTT may yield even higher success rates. The superiority of catheter ablation over antiarrhythmic medication demonstrated by Ling et al. ( 19 ) in their randomized study becomes even more compelling when operators can use PTT to optimize procedural outcomes. Earlier work by Zhu et al. ( 20 ) established the foundation for PVC ablation efficacy, while our PTT metric provides a tool to enhance these established benefits. Kumar et al. ( 21 ) described novel epicardial sites in the right ventricular inflow tract where standard mapping criteria may be less reliable. For such challenging anatomical locations, PTT offers an additional dimension of assessment that complements traditional mapping parameters. Long-Term Outcomes and Clinical Significance Extending beyond acute success, our long-term analysis revealed that patients with durable success had significantly shorter PTT compared to those who experienced recurrence (11.5s vs 28.5s, p = 0.008). This suggests PTT's value extends beyond immediate procedural outcomes and may reflect the quality and durability of lesion formation. Interestingly, LAT values were similar between groups with and without recurrence, further supporting PTT's superior predictive value. This finding has important implications for procedural endpoints, as discussed in the HRS/EHRA/APHRS/LAHRS consensus statement by Cronin et al. ( 1 ). Rather than relying solely on acute PVC elimination, operators might consider PTT as an additional marker of lesion adequacy. Sites where PVCs are eliminated rapidly may represent more effective ablation with better long-term durability, while sites requiring prolonged energy delivery for PVC suppression may be at higher risk for recurrence. However, we observed cases of early recurrence despite short initial PTT (< 10 seconds), which may represent scenarios with multiple exit sites from a single focus or incomplete elimination of the arrhythmogenic substrate. These outliers highlight that while PTT is a powerful predictor, it should be integrated with comprehensive mapping rather than used in isolation, consistent with the systematic approach to ventricular arrhythmias described by Tanawuttiwat et al. ( 22 ). Limitations This study has several important limitations. First, the sample size of 54 patients, while sufficient for initial validation of the PTT concept, requires larger multicenter validation. Second, the relatively low per-application success rate (17.4%) versus per-patient rate (92.6%) reflects our methodology of counting each ablation attempt separately, which may overestimate failure rates. Third, contact force data was not systematically analyzed in relation to PTT, which could provide additional mechanistic insights. Fourth, we did not prospectively test whether using PTT to guide procedural decisions improves outcomes compared to standard approaches. Fifth, location-specific analysis was limited by small sample sizes, particularly for LVOT (n = 4) and other LV sites (n = 3), precluding definitive statistical comparisons between anatomical locations. The observed trends require validation in larger cohorts. Finally, the physiological mechanisms underlying PTT variations remain incompletely understood and warrant further investigation. PTT may be prolonged in patients with infrequent PVCs due to the sporadic nature rather than ineffective ablation. Additionally, local edema from repeated ablation attempts could potentially affect subsequent PTT measurements, though our analysis showed minimal within-patient correlation (ICC = 0.0004). Future Directions This pilot study establishes PTT as a promising metric warranting further investigation. Prospective multicenter studies should validate PTT across different PVC subtypes, ablation technologies, and patient populations. Randomized trials comparing PTT-guided versus conventional ablation strategies could determine whether incorporating PTT improves procedural efficiency and outcomes. Development of automated PTT calculation with real-time display could facilitate clinical implementation. Investigation of PTT in other arrhythmias such as atrial fibrillation or ventricular tachycardia could determine broader applicability of termination time metrics. Conclusion PVC Termination Time represents a novel intra-procedural metric that independently predicts acute success in PVC ablation, with an optimal threshold around 25 seconds for most locations, though location-specific variability and small sample sizes in certain anatomical sites warrant cautious interpretation. PTT provides a simple, real-time tool that complements traditional mapping by directly gauging lesion effectiveness. While this pilot study demonstrates proof-of-concept, larger multicenter validation is needed to confirm these findings and establish PTT's role in optimizing PVC ablation procedures. PERSPECTIVES Competency in Medical Knowledge Understanding the temporal dynamics of PVC elimination during radiofrequency ablation provides insights beyond traditional spatial mapping parameters for predicting procedural success. Location-specific variations in PTT, particularly for challenging sites like the LV summit, should inform procedural expectations and decision-making. Translational Outlook Future research should prospectively validate PTT-guided ablation strategies in randomized trials and explore automated real-time PTT monitoring systems to optimize procedural workflows. Investigation of whether PTT thresholds can be refined based on specific anatomical locations and tissue characteristics will be important for personalized ablation strategies. Declarations CONFLICT OF INTEREST STATEMENT None to declare ETHICS STATEMENT This study was approved by Toho University, Ohashi Medical Center Ethics Committee (No. H22006) PATIENT CONSENT STATEMENT We applied the opt-out method to obtain consent for this study. DATA AVAILABILITY STATEMENT The data that support the findings of this study are available from the corresponding author upon reasonable request. FUNDING STATEMENT The authors received no specific funding for this work. ACKNOWLEDGMENTS This study was conducted with the assistance of all staff at Toho University, Ohashi Medical Center and SUBARU Health Insurance Society Ota Memorial Hospital. The authors are grateful to the clinical physiology staff for their assistance with data collection and processing. We also thank the biostatistics consultation service at Toho University for their guidance on statistical analysis approaches. References Cronin EM, Bogun FM, Maury P, Peichl P, Chen M, Namboodiri N, et al. 2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias. Heart Rhythm. 2020;17:e2–154. Latchamsetty R, Yokokawa M, Morady F, Kim HM, Mathew S, Tilz R, et al. Multicenter outcomes for catheter ablation of idiopathic premature ventricular complexes. JACC Clin Electrophysiol. 2015;1:116–23. Aliot EM, Stevenson WG, Almendral-Garrote JM, Bogun F, Calkins CH, Delacretaz E, et al. 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Garg L, Gupta T, Sahara N, Kim J, Chen S, Liu A, et al. Prolonged endocardial ablation for left ventricular summit premature ventricular contractions: efficacy and safety. JACC Clin Electrophysiol. 2022;8:465–76. Bazan V, Gerstenfeld EP, Garcia FC, Bala R, Rivas N, Dixit S, et al. Site-specific twelve-lead ECG features to identify an epicardial origin for left ventricular tachycardia in the absence of myocardial infarction. Heart Rhythm. 2007;4:1403–10. Sosa E, Scanavacca M, d’Avila A, Pilleggi F. A new technique to perform epicardial mapping in the electrophysiology laboratory. J Cardiovasc Electrophysiol. 1996;7:531–6. Nakagawa H, Beckman KJ, McClelland JH, Wang X, Arruda M, Santoro I, et al. Radiofrequency catheter ablation of idiopathic left ventricular tachycardia guided by a Purkinje potential. Circulation. 1993;88:2607–17. Ouyang F, Fotuhi P, Ho SY, Hebe J, Volkmer M, Goya M, et al. 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Radiofrequency catheter ablation for management of symptomatic ventricular ectopic activity. J Am Coll Cardiol. 1995;26:843–9. Kumar S, Barbhaiya CR, Baldinger SH, Bunch TJ, Chung MK, Koplan BA, et al. Epicardial pacing in right ventricular inflow tract: a novel site for idiopathic ventricular arrhythmias. Heart Rhythm. 2015;12:927–36. Tanawuttiwat T, Nazarian S, Calkins H. The role of catheter ablation in the management of ventricular tachycardia. Eur Heart J. 2016;37:594–609. Additional Declarations No competing interests reported. Supplementary Files SupplementalFigure1.docx Cite Share Download PDF Status: Published Journal Publication published 09 Dec, 2025 Read the published version in Journal of Interventional Cardiac Electrophysiology → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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14:47:22","extension":"xml","order_by":21,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":87524,"visible":true,"origin":"","legend":"","description":"","filename":"33f067d19f69492f8f3a564a6ab7103f1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7698543/v1/30e2e74c8ee021860798656e.xml"},{"id":93239789,"identity":"e54ee8f7-de0d-4599-b000-7609c15a70af","added_by":"auto","created_at":"2025-10-10 14:39:22","extension":"html","order_by":22,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":99730,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7698543/v1/ba909404ceb8a3832e99205b.html"},{"id":93239763,"identity":"ed67523b-ea77-4685-8d1f-8b5ef1fe6919","added_by":"auto","created_at":"2025-10-10 14:39:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":246048,"visible":true,"origin":"","legend":"\u003cp\u003eExamples of the measurement of earliest local activation time on the intracardiac bipolar electrogram compared to 12-lead surface ECG. (A) Earliest time pre-QRS of PVC -42 ms in bipolar electrogram with successful RF ablation (B) Examples of activation mapping (C) Examples of peak frequency analysis\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7698543/v1/0c4ec4a461428e515d80a855.png"},{"id":93239761,"identity":"d408a1f9-65f0-44a9-8a61-529f89783854","added_by":"auto","created_at":"2025-10-10 14:39:21","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":85098,"visible":true,"origin":"","legend":"\u003cp\u003eLinear Correlation Between LAT and PVC Termination Time Scatter plot with linear regression line showing the relationship between local activation time (LAT) and PVC termination time (PTT). A statistically significant inverse correlation was observed (r = -0.45, p \u0026lt; 0.001), suggesting that earlier LAT is associated with shorter PVC termination time.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7698543/v1/6d633d6eacf72fd47b47b197.png"},{"id":93239762,"identity":"a5bb1052-c129-42fa-8aaa-249107ee6124","added_by":"auto","created_at":"2025-10-10 14:39:21","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":67667,"visible":true,"origin":"","legend":"\u003cp\u003ePTT and LAT in Success vs. Failure Applications Violin plots illustrating the distribution of PVC termination time (left) and local activation time (LAT, right) stratified by ablation outcome. The plots show significant differences between success and failure application groups for both variables. Median PVC termination time was markedly shorter in successful applications (12 seconds [IQR 8-18] vs. 62 seconds [IQR 45-75], p \u0026lt; 0.0001), while LAT was significantly earlier in successful cases (-36 ms [IQR -42 to -28] vs. -26.5 ms [IQR -32 to -18], p \u0026lt; 0.01). Data presented as median with interquartile range.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7698543/v1/1b4146aeea4c4db553a3ba18.png"},{"id":93242943,"identity":"a100cfd4-6add-4ec1-ab17-acc9f82f1537","added_by":"auto","created_at":"2025-10-10 14:55:21","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":60289,"visible":true,"origin":"","legend":"\u003cp\u003eReceiver Operating Characteristic Curves for PTT and LAT Receiver operating characteristic (ROC) curves comparing the predictive performance of PVC termination time (PTT) and local activation time (LAT) for procedural success. The area under the curve (AUC) for PTT was 0.933, indicating excellent predictive accuracy, while LAT yielded an AUC of 0.719. The optimal cutoff for PTT was identified as 25 seconds, based on the Youden index. PTT outperformed LAT across the range of false positive rates, highlighting its superiority as a real-time procedural marker for successful ablation.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7698543/v1/c7ef496631b42a8b9f918acf.png"},{"id":93242945,"identity":"552aceba-7d62-4d9c-abb8-a9017caa329a","added_by":"auto","created_at":"2025-10-10 14:55:21","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":192075,"visible":true,"origin":"","legend":"\u003cp\u003eTwo-Dimensional Risk Surface Mapping Success Probability Two-dimensional contour plot illustrating the predicted probability of acute procedural success in relation to local activation time (LAT, x-axis) and PVC termination time (y-axis). Color shading indicates the probability of ablation success as estimated from a multivariate logistic regression model incorporating both variables. Contour lines represent success probability thresholds at 50% (red), 60% (orange), 70% (yellow), 80% (green), 90% (cyan), and 95% (blue). Higher success probabilities were observed in regions characterized by earlier LAT (more negative values) and shorter termination times, with the ≥90% zone concentrated at LAT \u0026lt; -30 ms and termination time \u0026lt; 20 s.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7698543/v1/49063a76f8dccff3d9e2796e.png"},{"id":98243527,"identity":"5b704b4a-368c-4e8a-a615-332a1075a339","added_by":"auto","created_at":"2025-12-15 16:08:37","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1294557,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7698543/v1/ee16d1ee-71a3-4fb9-9377-75aa64fecc18.pdf"},{"id":93240731,"identity":"09a6902f-7a60-4a5e-ac8a-5d2cbfac9bdb","added_by":"auto","created_at":"2025-10-10 14:47:21","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":235733,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalFigure1.docx","url":"https://assets-eu.researchsquare.com/files/rs-7698543/v1/71e9d01841fb454952596121.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"PVC Termination Time: A Novel Real-Time Predictor of Ablation Success","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCatheter ablation has emerged as an effective treatment strategy for symptomatic premature ventricular contractions (PVCs), with success rates typically exceeding 80% for most PVC subtypes (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Accurate identification and effective elimination of the arrhythmogenic focus remain essential determinants of procedural success. Conventionally, local activation time (LAT) has served as the primary mapping parameter for targeting ablation sites, with earlier (more negative) LAT values generally indicating closer proximity to the site of origin (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eWhile LAT-guided mapping has demonstrated clinical utility, it provides only static information about the target site and fails to capture the dynamic tissue-catheter interaction during energy delivery. Previous investigations have established that LAT values earlier than \u0026minus;\u0026thinsp;30 ms are associated with favorable outcomes (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e), but LAT alone cannot assess the quality of lesion formation or the arrhythmogenic substrate's responsiveness to ablation energy.\u003c/p\u003e\u003cp\u003eIn everyday clinical practice, electrophysiologists frequently observe that the rapidity with which PVCs are eliminated after radiofrequency (RF) energy initiation may be more predictive of procedural success than pre-ablation mapping parameters. However, this temporal relationship between ablation initiation and PVC elimination has not been systematically evaluated as a predictive metric in the literature.\u003c/p\u003e\u003cp\u003eWe hypothesized that the interval from ablation onset to PVC elimination, which we have termed \"PVC Termination Time (PTT),\" represents a more direct and physiologically relevant predictor of successful ablation. This pilot study aimed to: (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) evaluate the predictive power of PTT compared to conventional LAT, (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) determine the optimal PTT threshold for procedural success, (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e) assess location-specific PTT variations, and (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e) examine the incremental value of combining PTT with LAT for enhanced intra-procedural decision-making.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStudy Population\u003c/h2\u003e\u003cp\u003eWe performed an analysis of 310 ablation applications conducted in 54 consecutive PVC patients (mean age 58\u0026thinsp;\u0026plusmn;\u0026thinsp;12 years, 62% male) at a multi-center institute between January 2022 and December 2024. Inclusion criteria encompassed adult patients (\u0026ge;\u0026thinsp;18 years) undergoing catheter ablation for symptomatic, high-frequency, and/or drug-refractory PVCs. We prospectively collected clinical data, electrocardiogram (ECG), and intracardiac electrogram data. All patients underwent comprehensive evaluation including 12-lead ECG, 24-hour Holter monitoring, and transthoracic echocardiography. PVC burden was quantified as the percentage of PVCs relative to total heartbeats during 24-hour monitoring (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e). Anti-arrhythmic medications were discontinued for at least five half-lives before the procedure. Patients without spontaneous PVCs before the procedure were excluded. Patients with structural heart disease (previous myocardial infarction, cardiomyopathy with LVEF\u0026thinsp;\u0026lt;\u0026thinsp;40%, congenital heart disease, or cardiac sarcoidosis) were also excluded. Only patients with monomorphic PVCs of local origin based on ECG and electrophysiological criteria were included. The study protocol was approved by our institutional review board (H22006), and all patients provided written informed consent.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eElectrophysiological Study and Ablation Procedure\u003c/h3\u003e\n\u003cp\u003eAll procedures were performed without sedation or general anesthesia to preserve spontaneous PVC frequency; however, local anesthesia at vascular access sites and minimal sedation were administered as needed for patient comfort. Vascular access was obtained via the femoral vein and/or artery based on suspected PVC origin. A quadripolar catheter was positioned in the right ventricular apex for timing reference. Activation mapping was performed using the EnSite NavX system (Abbott, Chicago, IL) with an HD Grid high-density electrode catheter during spontaneous PVCs (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e). LAT was measured as the interval between the earliest deflection of the local bipolar electrogram and the onset of the surface QRS complex during PVCs, with negative values indicating pre-systolic activation. Unipolar electrograms were analyzed for QS morphology at each target site. All potential ablation sites including RVOT, LVOT, aortic cusps, and epicardial sites were systematically evaluated before ablation. LAT measurements were reviewed by two experienced electrophysiologists with discrepancies resolved by consensus.\u003c/p\u003e\u003cp\u003ePace mapping was performed at potential target sites using minimum output for myocardial capture (typically 2 mA above threshold) with 2.0 ms pulse width. A pace mapping score was calculated based on matching leads between paced QRS morphology and clinical PVC (12/12 indicating perfect match). Intracardiac electrogram characteristics suggesting PVC origin included sharp presystolic potentials, high-frequency components, and fractionated signals. For infrequent PVCs, programmed ventricular stimulation and/or isoproterenol infusion (1\u0026ndash;5 \u0026micro;g/min) was used for induction.\u003c/p\u003e\u003cp\u003eRadiofrequency energy was delivered at target sites identified through activation mapping, pace mapping, and electrogram analysis. Target sites were selected based on earliest activation with LAT\u0026thinsp;\u0026ge;\u0026thinsp;20 ms pre-QRS, pace mapping score\u0026thinsp;\u0026ge;\u0026thinsp;11/12, and/or characteristic electrogram patterns. RF energy was delivered using a TactiFlex SE ablation catheter (Abbott), a 3.5-mm irrigated-tip catheter with contact force sensing. Power settings were 30\u0026ndash;40 W for endocardial sites and 20\u0026ndash;30 W for high impedance sites. Maximum temperature was limited to 43\u0026deg;C with irrigation flow rates of 17\u0026ndash;30 mL/min. RF was applied for up to 60\u0026ndash;120 seconds at each target site.\u003c/p\u003e\u003cp\u003ePTT was prospectively recorded for each ablation attempt, defined as the interval from RF initiation to complete elimination of the targeted PVC, measured in seconds. Complete elimination was defined as the last observed PVC of that morphology, after which no further PVCs occurred during remaining RF application. If PVCs persisted beyond 60 seconds, the catheter was repositioned and those applications were classified as unsuccessful.\u003c/p\u003e\n\u003ch3\u003eDefinition of Outcomes\u003c/h3\u003e\n\u003cp\u003eAcute procedural success was defined as complete elimination of the targeted PVC during the procedure with no recurrence during 30-minute observation including programmed stimulation and isoproterenol infusion. Long-term success was defined as absence of the targeted PVC on 12-lead ECG and 24-hour Holter at follow-up visits, with PVC burden\u0026thinsp;\u0026lt;\u0026thinsp;5%.\u003c/p\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eStatistical analyses were performed using R version 4.0.3. Continuous variables were expressed as median [interquartile range] for non-normally distributed data; categorical variables as counts and percentages. Comparisons between groups used Mann-Whitney U test for continuous variables and chi-square test for categorical variables.\u003c/p\u003e\u003cp\u003eReceiver operating characteristic (ROC) analysis evaluated the predictive performance of LAT and PTT, with optimal cutoff values determined using the Youden index. Logistic regression models assessed the independent contribution of each parameter to procedural success. Mixed-effects logistic regression with patient-specific random intercepts accounted for multiple applications per patient. The intraclass correlation coefficient (ICC) was calculated to assess within-patient correlation. ROC confidence intervals were calculated using cluster bootstrap resampling (1000 iterations). A sensitivity analysis using only the first ablation application per patient was conducted. A two-dimensional risk surface was generated to visualize the relationship between LAT, PTT, and probability of success. Statistical significance was defined as p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eBaseline Characteristics and Acute Success Rate\u003c/h2\u003e\u003cp\u003eAmong 54 patients, the mean pre-procedural PVC burden was 22\u0026thinsp;\u0026plusmn;\u0026thinsp;11% of total heartbeats. Acute PVC elimination was achieved in 50 patients (92.6%). Successful ablation sites were most commonly in the right ventricular outflow tract (46%), followed by the left ventricular outflow tract and adjacent structures (30%), LV summit (15%), other RV locations (4%), and other LV locations (5%) (Table\u0026nbsp;1).\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003ePredictive Value of PTT versus LAT\u003c/h3\u003e\n\u003cp\u003eAcross 54 successful ablation applications (one per successful patient), median PTT was 12 seconds [IQR 8\u0026ndash;18], range 2\u0026ndash;59 seconds. LAT values showed median \u0026minus;\u0026thinsp;36 ms [IQR \u0026minus;\u0026thinsp;42 to -28], range \u0026minus;\u0026thinsp;55 to 0 ms. In successful applications, PTT showed an inverse relationship with LAT: earlier LAT values were associated with shorter PTT (r = -0.45, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\u003c/p\u003e\u003cp\u003eComparing successful versus failed applications across all 310 attempts, median PTT in successful applications was significantly shorter than in failed applications (12s [IQR 8\u0026ndash;18] vs 62s [IQR 45\u0026ndash;75], p\u0026thinsp;\u0026lt;\u0026thinsp;0.0001; Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Similarly, LAT was significantly earlier in successful applications (median \u0026minus;\u0026thinsp;36ms [IQR \u0026minus;\u0026thinsp;42 to -28] vs -26.5ms [IQR \u0026minus;\u0026thinsp;32 to -18], p\u0026thinsp;\u0026lt;\u0026thinsp;0.01; Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eROC analysis confirmed both parameters as significant predictors of procedural success, but PTT demonstrated superior discriminative ability (AUC\u0026thinsp;=\u0026thinsp;0.933, 95% CI 0.889\u0026ndash;0.969) compared to LAT (AUC\u0026thinsp;=\u0026thinsp;0.719, 95% CI 0.640\u0026ndash;0.792). The optimal PTT cutoff was 25 seconds, yielding 88.4% sensitivity and 83.2% specificity for acute success. For LAT, the optimal cutoff was \u0026minus;\u0026thinsp;30 ms (sensitivity 72.1%, specificity 68.4%). The combined PTT\u0026thinsp;+\u0026thinsp;LAT model did not significantly improve the AUC over PTT alone (AUC\u0026thinsp;=\u0026thinsp;0.934 vs 0.933, p\u0026thinsp;=\u0026thinsp;0.78).\u003c/p\u003e\n\u003ch3\u003eLocation-Specific PTT Analysis\u003c/h3\u003e\n\u003cp\u003ePTT showed trends toward variation by anatomical location, though statistical comparison was limited by small sample sizes in several groups (LVOT n\u0026thinsp;=\u0026thinsp;4, LV other n\u0026thinsp;=\u0026thinsp;3). RVOT origins demonstrated median PTT of 12s [5\u0026ndash;20], LVOT 7s [6\u0026ndash;11], and LV summit 13s [5\u0026ndash;38] with notably wider IQR (Table\u0026nbsp;3). The wide IQR in LV summit cases is consistent with the known challenges of this location described by Garg et al. (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e).\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eMultivariable and Mixed-Effects Analysis\u003c/h2\u003e\u003cp\u003eIn multivariate logistic regression, both PTT and LAT were independent predictors of success (shorter PTT: β=-0.090\u0026thinsp;\u0026plusmn;\u0026thinsp;0.013, p\u0026thinsp;\u0026lt;\u0026thinsp;0.001; more negative LAT: β=-0.064\u0026thinsp;\u0026plusmn;\u0026thinsp;0.023, p\u0026thinsp;=\u0026thinsp;0.005). Mixed-effects modeling accounting for patient-level clustering confirmed PTT remained a strong predictor (p\u0026thinsp;\u0026lt;\u0026thinsp;0.001) while LAT did not remain significant (p\u0026thinsp;=\u0026thinsp;0.089). The ICC was 0.0004, indicating negligible within-patient correlation between applications, likely due to high variability in catheter position and contact between attempts. Sensitivity analysis using only first ablation per patient showed PTT was significant (p\u0026thinsp;=\u0026thinsp;0.0012) but LAT was not (p\u0026thinsp;=\u0026thinsp;0.352).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003eTwo-Dimensional Risk Analysis\u003c/h2\u003e\u003cp\u003eA two-dimensional risk surface plot illustrating the relationship between LAT, PTT, and probability of success showed highest predicted success probabilities (\u0026gt;\u0026thinsp;90%) when LAT was earlier than \u0026minus;\u0026thinsp;30 ms and PTT was shorter than 20 seconds (Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e5\u003c/span\u003e). Conversely, lowest predicted success probabilities (\u0026lt;\u0026thinsp;10%) were seen when LAT was later than \u0026minus;\u0026thinsp;20 ms and PTT exceeded 40 seconds. This analysis suggested a continuous gradient of success probability rather than sharp binary threshold.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003eAdditional Electrophysiological Parameters\u003c/h2\u003e\u003cp\u003ePeak frequency at ablation sites and ΔLAT (difference between first deflection and near-field signal timing) showed no significant association with acute procedural success (p\u0026thinsp;=\u0026thinsp;0.32 and p\u0026thinsp;=\u0026thinsp;0.47, respectively).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003eLong-Term Follow-Up Outcomes\u003c/h2\u003e\u003cp\u003eLong-term follow-up (mean 18\u0026thinsp;\u0026plusmn;\u0026thinsp;6 months) was available in 48 of 50 patients with acute success. Overall long-term success rate was 85.4% (41/48). Patients remaining free of PVC recurrence had significantly shorter median PTT during index procedure than those with recurrence (11.5s [IQR 8\u0026ndash;15] vs 28.5s [IQR 20\u0026ndash;38], p\u0026thinsp;=\u0026thinsp;0.008), while LAT values were similar (median \u0026minus;\u0026thinsp;35ms [IQR \u0026minus;\u0026thinsp;40 to -28] vs -33ms [IQR \u0026minus;\u0026thinsp;38 to -25], p\u0026thinsp;=\u0026thinsp;0.42).\u003c/p\u003e\u003cp\u003eNotably, among the 7 patients with recurrence, 5 had PTT\u0026thinsp;\u0026gt;\u0026thinsp;25 seconds during the index procedure, suggesting that prolonged PTT may indicate either intramural origin or inadequate lesion formation. Two patients with very short PTT (\u0026lt;\u0026thinsp;10 seconds) but late recurrence may represent cases of multiple exit sites or incomplete elimination of the arrhythmogenic substrate.\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study introduces and validates PVC Termination Time as a novel real-time indicator of acute ablation success. PTT demonstrated superior predictive power compared to conventional LAT mapping, with a practical threshold of 25 seconds serving as an objective intra-procedural guide. Our findings provide important insights into the dynamic aspects of PVC ablation that complement traditional static mapping parameters.\u003c/p\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003eMechanistic Insights and Pathophysiological Implications\u003c/h2\u003e\u003cp\u003ePTT captures dynamic procedural information that LAT alone cannot provide. While LAT reflects the spatial relationship between the catheter and the arrhythmogenic focus (\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e), PTT incorporates multiple factors including tissue response to ablation energy, catheter contact quality, tissue characteristics, and lesion formation efficiency\u0026mdash;factors not captured by pre-ablation mapping. These observations align with previous studies by Latchamsetty et al. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) and Choi et al. (\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e) highlighting limitations of pre-procedural mapping parameters in predicting ablation success.\u003c/p\u003e\u003cp\u003eA short PTT likely indicates several favorable conditions: excellent catheter-tissue contact, superficial PVC origin allowing rapid transmural lesion formation, and absence of protective tissue barriers such as epicardial fat or intramural scar. Conversely, prolonged PTT might indicate deeper intramural focus, suboptimal catheter contact, presence of epicardial fat as described by Bazan et al. (\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e) and Sosa et al. (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e), or proximity to high-flow vascular structures causing heat sink effect. When the catheter tip is well apposed to tissue with minimal movement, energy delivery is more efficient and lesion formation more rapid, supporting the use of PTT as a surrogate for lesion quality in real time.\u003c/p\u003e\u003cp\u003eThe inverse relationship between LAT and PTT in successful cases suggests that when the catheter is truly at the site of origin (earliest LAT), less time is required for effective ablation. This aligns with the fundamental electrophysiological principles established by Nakagawa et al. (\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e) for Purkinje-related arrhythmias and extends to PVC ablation. However, we observed outliers where successful ablation occurred despite prolonged PTT (\u0026gt;\u0026thinsp;25s) with only moderately early LAT values. These cases likely represent scenarios where mapping was challenging due to infrequent PVCs, unstable catheter positioning in difficult locations like aortic cusps as described by Ouyang et al. (\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e), or intramural origin requiring sustained energy delivery.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\u003ch2\u003eLocation-Specific Considerations\u003c/h2\u003e\u003cp\u003eOur location-specific analysis revealed important PTT variations that have direct clinical implications. RVOT origins showed the shortest PTT (median 10s), consistent with the relatively thin myocardial wall and accessibility of this region. This finding corroborates previous work by Azegami et al. (\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e) demonstrating the favorable anatomical characteristics of RVOT for ablation. LVOT origins required slightly longer ablation times (median 14s), possibly reflecting thicker myocardium or proximity to coronary vasculature requiring more cautious energy delivery, as noted by Yamada et al. (\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e) in their analysis of preferential conduction patterns.\u003c/p\u003e\u003cp\u003eMost notably, LV summit origins showed median PTT of 13s with notably wider variability (IQR 5-38s), suggesting heterogeneous tissue characteristics in this region. While the median value was similar to other locations, the broad IQR indicates that some LV summit cases may require extended ablation times. This finding aligns with recent work by Watanabe et al. (\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e) who reported arrhythmia elimination times of approximately 12\u0026thinsp;\u0026plusmn;\u0026thinsp;12s for successful endocardial ablations versus 32\u0026thinsp;\u0026plusmn;\u0026thinsp;24s for epicardial approaches in LV summit PVCs. Furthermore, Garg et al. (\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e) demonstrated that prolonged duration ablation from endocardial locations can be a successful strategy for LV summit PVCs, supporting our observation that longer PTT may be acceptable or even necessary for certain anatomical locations.\u003c/p\u003e\u003cp\u003eThese location-specific variations suggest that while a general 25-second threshold provides useful guidance, operators should consider anatomical context when interpreting PTT. For suspected intramural origins or cases with wide PTT variability such as observed in our LV summit cohort, operators should consider individual tissue characteristics rather than applying rigid time thresholds, whereas for typical RVOT origins, failure to eliminate PVCs within 15\u0026ndash;20 seconds should prompt repositioning. This approach is consistent with the site-specific strategies advocated by Hutchinson and Garcia (\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e) in their comprehensive review of outflow tract arrhythmia management.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003eClinical and Procedural Implications\u003c/h2\u003e\u003cp\u003eThe identification of 25 seconds as an optimal PTT cutoff has important practical implications. In our study, PVCs in successful ablations were often eliminated well before 25 seconds (median 12 seconds). Our 2D risk analysis indicated that PTT\u0026thinsp;\u0026le;\u0026thinsp;20 seconds combined with LAT more negative than \u0026minus;\u0026thinsp;30 ms yielded\u0026thinsp;\u0026gt;\u0026thinsp;90% predicted success. Thus, while 25 seconds is statistically optimal, an even shorter PTT could be used as a stricter intra-procedural gauge.\u003c/p\u003e\u003cp\u003eThis threshold enables objective decision-making during procedures, similar to the V2 transition ratio described by Betensky et al. (\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e) for differentiating PVC origins. If PVCs persist beyond 25 seconds of RF delivery at typical endocardial sites, the probability of success at that site falls dramatically, suggesting further energy delivery may yield diminishing returns. This approach could expedite decision-making, potentially reducing unnecessary lesion delivery, procedure time, and complications.\u003c/p\u003e\u003cp\u003eFor complex cases such as suspected intramural PVCs or unusual locations like the pulmonary artery described by Sekiguchi et al. (\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e) or the mitral annulus reported by Tada et al. (\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e), incorporating PTT provides immediate feedback about whether the current strategy is effective. Similarly, for epicardial sites accessed via the technique described by Sosa et al. (\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e), PTT may help determine when to pursue alternative approaches.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003eComparison with Contemporary Literature\u003c/h2\u003e\u003cp\u003eOur findings complement recent advances in PVC ablation strategy. Sabzwari et al. (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e) found that large differences between bipolar and unipolar activation times (ΔLATBi-Uni\u0026thinsp;\u0026ge;\u0026thinsp;15 ms) predicted the need for bi-ventricular ablation for outflow tract PVCs, conceptually paralleling our finding that PTT\u0026thinsp;\u0026gt;\u0026thinsp;25s suggests a potentially intramural focus requiring more extensive ablation.\u003c/p\u003e\u003cp\u003eIm et al. (\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e) identified factors like female sex, single PVC morphology, and very early bipolar activation (\u0026gt;\u0026thinsp;24 ms pre-QRS) as predictors of durable success in their Europace study. While these factors relate to baseline patient and PVC characteristics, PTT provides immediate procedural feedback that can guide real-time decision-making. The combination of favorable baseline factors and rapid PTT may yield even higher success rates.\u003c/p\u003e\u003cp\u003eThe superiority of catheter ablation over antiarrhythmic medication demonstrated by Ling et al. (\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e) in their randomized study becomes even more compelling when operators can use PTT to optimize procedural outcomes. Earlier work by Zhu et al. (\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e) established the foundation for PVC ablation efficacy, while our PTT metric provides a tool to enhance these established benefits.\u003c/p\u003e\u003cp\u003eKumar et al. (\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e) described novel epicardial sites in the right ventricular inflow tract where standard mapping criteria may be less reliable. For such challenging anatomical locations, PTT offers an additional dimension of assessment that complements traditional mapping parameters.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e\u003ch2\u003eLong-Term Outcomes and Clinical Significance\u003c/h2\u003e\u003cp\u003eExtending beyond acute success, our long-term analysis revealed that patients with durable success had significantly shorter PTT compared to those who experienced recurrence (11.5s vs 28.5s, p\u0026thinsp;=\u0026thinsp;0.008). This suggests PTT's value extends beyond immediate procedural outcomes and may reflect the quality and durability of lesion formation. Interestingly, LAT values were similar between groups with and without recurrence, further supporting PTT's superior predictive value.\u003c/p\u003e\u003cp\u003eThis finding has important implications for procedural endpoints, as discussed in the HRS/EHRA/APHRS/LAHRS consensus statement by Cronin et al. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e). Rather than relying solely on acute PVC elimination, operators might consider PTT as an additional marker of lesion adequacy. Sites where PVCs are eliminated rapidly may represent more effective ablation with better long-term durability, while sites requiring prolonged energy delivery for PVC suppression may be at higher risk for recurrence.\u003c/p\u003e\u003cp\u003eHowever, we observed cases of early recurrence despite short initial PTT (\u0026lt;\u0026thinsp;10 seconds), which may represent scenarios with multiple exit sites from a single focus or incomplete elimination of the arrhythmogenic substrate. These outliers highlight that while PTT is a powerful predictor, it should be integrated with comprehensive mapping rather than used in isolation, consistent with the systematic approach to ventricular arrhythmias described by Tanawuttiwat et al. (\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec21\" class=\"Section2\"\u003e\u003ch2\u003eLimitations\u003c/h2\u003e\u003cp\u003eThis study has several important limitations. First, the sample size of 54 patients, while sufficient for initial validation of the PTT concept, requires larger multicenter validation. Second, the relatively low per-application success rate (17.4%) versus per-patient rate (92.6%) reflects our methodology of counting each ablation attempt separately, which may overestimate failure rates. Third, contact force data was not systematically analyzed in relation to PTT, which could provide additional mechanistic insights. Fourth, we did not prospectively test whether using PTT to guide procedural decisions improves outcomes compared to standard approaches. Fifth, location-specific analysis was limited by small sample sizes, particularly for LVOT (n\u0026thinsp;=\u0026thinsp;4) and other LV sites (n\u0026thinsp;=\u0026thinsp;3), precluding definitive statistical comparisons between anatomical locations. The observed trends require validation in larger cohorts. Finally, the physiological mechanisms underlying PTT variations remain incompletely understood and warrant further investigation.\u003c/p\u003e\u003cp\u003ePTT may be prolonged in patients with infrequent PVCs due to the sporadic nature rather than ineffective ablation. Additionally, local edema from repeated ablation attempts could potentially affect subsequent PTT measurements, though our analysis showed minimal within-patient correlation (ICC\u0026thinsp;=\u0026thinsp;0.0004).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec22\" class=\"Section2\"\u003e\u003ch2\u003eFuture Directions\u003c/h2\u003e\u003cp\u003eThis pilot study establishes PTT as a promising metric warranting further investigation. Prospective multicenter studies should validate PTT across different PVC subtypes, ablation technologies, and patient populations. Randomized trials comparing PTT-guided versus conventional ablation strategies could determine whether incorporating PTT improves procedural efficiency and outcomes. Development of automated PTT calculation with real-time display could facilitate clinical implementation. Investigation of PTT in other arrhythmias such as atrial fibrillation or ventricular tachycardia could determine broader applicability of termination time metrics.\u003c/p\u003e\u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003ePVC Termination Time represents a novel intra-procedural metric that independently predicts acute success in PVC ablation, with an optimal threshold around 25 seconds for most locations, though location-specific variability and small sample sizes in certain anatomical sites warrant cautious interpretation. PTT provides a simple, real-time tool that complements traditional mapping by directly gauging lesion effectiveness. While this pilot study demonstrates proof-of-concept, larger multicenter validation is needed to confirm these findings and establish PTT's role in optimizing PVC ablation procedures.\u003c/p\u003e\u003cdiv id=\"Sec24\" class=\"Section2\"\u003e\u003ch2\u003ePERSPECTIVES\u003c/h2\u003e\u003cp\u003e\u003cstrong\u003eCompetency in Medical Knowledge\u003c/strong\u003e\u003cp\u003eUnderstanding the temporal dynamics of PVC elimination during radiofrequency ablation provides insights beyond traditional spatial mapping parameters for predicting procedural success. Location-specific variations in PTT, particularly for challenging sites like the LV summit, should inform procedural expectations and decision-making.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eTranslational Outlook\u003c/strong\u003e\u003cp\u003eFuture research should prospectively validate PTT-guided ablation strategies in randomized trials and explore automated real-time PTT monitoring systems to optimize procedural workflows. Investigation of whether PTT thresholds can be refined based on specific anatomical locations and tissue characteristics will be important for personalized ablation strategies.\u003c/p\u003e\u003c/p\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eCONFLICT OF INTEREST STATEMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNone to declare\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eETHICS STATEMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was approved by Toho University, Ohashi Medical Center Ethics Committee (No. H22006)\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePATIENT CONSENT STATEMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe applied the opt-out method to obtain consent for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDATA AVAILABILITY STATEMENT \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFUNDING STATEMENT \u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors received no specific funding for this work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eACKNOWLEDGMENTS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was conducted with the assistance of all staff at Toho University, Ohashi Medical Center and SUBARU Health Insurance Society Ota Memorial Hospital. The authors are grateful to the clinical physiology staff for their assistance with data collection and processing. We also thank the biostatistics consultation service at Toho University for their guidance on statistical analysis approaches.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eCronin EM, Bogun FM, Maury P, Peichl P, Chen M, Namboodiri N, et al. 2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias. Heart Rhythm. 2020;17:e2\u0026ndash;154.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLatchamsetty R, Yokokawa M, Morady F, Kim HM, Mathew S, Tilz R, et al. Multicenter outcomes for catheter ablation of idiopathic premature ventricular complexes. JACC Clin Electrophysiol. 2015;1:116\u0026ndash;23.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAliot EM, Stevenson WG, Almendral-Garrote JM, Bogun F, Calkins CH, Delacretaz E, et al. EHRA/HRS expert consensus on catheter ablation of ventricular arrhythmias. Europace. 2009;11:771\u0026ndash;817.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eAzegami K, Wilber DJ, Arruda M, Lin AC, Denman RA. Spatial resolution of pacemapping and activation mapping in patients with idiopathic right ventricular outflow tract tachycardia. J Cardiovasc Electrophysiol. 2005;16:823\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYamada T, Murakami Y, Yoshida N, Okada T, Shimizu T, Toyama J, et al. Preferential conduction across the ventricular outflow septum in ventricular arrhythmias originating from the aortic sinus cusp. J Am Coll Cardiol. 2007;50:884\u0026ndash;91.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChoi EK, Kumar S, Nagashima K, Lin KY, Chang D, Chung EH, et al. Better outcome of ablation for sustained outflow-tract ventricular tachycardia when tachycardia is inducible. Europace. 2018;20:130\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eIm SI, Kim SH, Kim JS, Lim HE, Lee KN, Pak HN, et al. Long-term prognosis of patients with premature ventricular complexes after radiofrequency catheter ablation. Europace. 2019;21:1507\u0026ndash;13.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGarg L, Gupta T, Sahara N, Kim J, Chen S, Liu A, et al. Prolonged endocardial ablation for left ventricular summit premature ventricular contractions: efficacy and safety. JACC Clin Electrophysiol. 2022;8:465\u0026ndash;76.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBazan V, Gerstenfeld EP, Garcia FC, Bala R, Rivas N, Dixit S, et al. Site-specific twelve-lead ECG features to identify an epicardial origin for left ventricular tachycardia in the absence of myocardial infarction. Heart Rhythm. 2007;4:1403\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSosa E, Scanavacca M, d\u0026rsquo;Avila A, Pilleggi F. A new technique to perform epicardial mapping in the electrophysiology laboratory. J Cardiovasc Electrophysiol. 1996;7:531\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eNakagawa H, Beckman KJ, McClelland JH, Wang X, Arruda M, Santoro I, et al. Radiofrequency catheter ablation of idiopathic left ventricular tachycardia guided by a Purkinje potential. Circulation. 1993;88:2607\u0026ndash;17.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eOuyang F, Fotuhi P, Ho SY, Hebe J, Volkmer M, Goya M, et al. Repetitive monomorphic ventricular tachycardia originating from the aortic sinus cusp: electrocardiographic characterization for guiding catheter ablation. J Am Coll Cardiol. 2002;39:500\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eWatanabe R, Nagashima K, Shirai Y, Hara Y, Takahashi Y, Okumura Y, et al. Anatomical vs electrophysiological approach for ablation of premature ventricular contractions originating from the left ventricular summit (ISESHIMA-SUMMIT Study). Europace. 2024;26:euae278.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHutchinson MD, Garcia FC. An organized approach to the localization, mapping, and ablation of outflow tract ventricular arrhythmias. J Cardiovasc Electrophysiol. 2013;24:1189\u0026ndash;97.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBetensky BP, Park RE, Marchlinski FE, Hutchinson MD, Garcia FC, Dixit S, et al. The V2 transition ratio: a new electrocardiographic criterion for distinguishing left from right ventricular outflow tract tachycardia origin. J Am Coll Cardiol. 2011;57:2255\u0026ndash;62.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSekiguchi Y, Aonuma K, Yamauchi Y, Obayashi T, Niwa A, Hachiya H, et al. Electrocardiographic and electrophysiologic characteristics of ventricular tachycardia originating within the pulmonary artery. J Am Coll Cardiol. 2005;45:887\u0026ndash;95.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTada H, Ito S, Naito S, Kurosaki K, Kubota S, Sugiyasu A, et al. Idiopathic ventricular arrhythmia arising from the mitral annulus: a distinct subgroup of idiopathic ventricular arrhythmias. J Am Coll Cardiol. 2005;45:877\u0026ndash;86.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSabzwari SRA, Rosenberg MA, Mann J, Gerstenfeld EP, Lin D, Marchlinski FE, et al. Limitations of unipolar signals in guiding successful outflow tract premature ventricular contraction ablation. JACC Clin Electrophysiol. 2022;8:843\u0026ndash;53.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLing Z, Liu Z, Su L, Zipunnikov V, Wu J, Du H, et al. Radiofrequency ablation versus antiarrhythmic medication for treatment of ventricular premature beats from the right ventricular outflow tract: prospective randomized study. Circ Arrhythm Electrophysiol. 2014;7:237\u0026ndash;43.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eZhu DW, Maloney JD, Simmons TW, Nitta J, Fitzgerald DM, Trohman RG, et al. Radiofrequency catheter ablation for management of symptomatic ventricular ectopic activity. J Am Coll Cardiol. 1995;26:843\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKumar S, Barbhaiya CR, Baldinger SH, Bunch TJ, Chung MK, Koplan BA, et al. Epicardial pacing in right ventricular inflow tract: a novel site for idiopathic ventricular arrhythmias. Heart Rhythm. 2015;12:927\u0026ndash;36.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eTanawuttiwat T, Nazarian S, Calkins H. The role of catheter ablation in the management of ventricular tachycardia. Eur Heart J. 2016;37:594\u0026ndash;609.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"premature ventricular contractions, catheter ablation, PVC termination time, LAT, real-time ablation marker","lastPublishedDoi":"10.21203/rs.3.rs-7698543/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7698543/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eDuring PVC ablation, operators need real-time feedback to optimize outcomes. We hypothesized that PVC Termination Time (PTT)—the interval from radiofrequency onset to PVC disappearance—would outperform local activation time (LAT) in predicting acute success.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObjectives:\u003c/strong\u003e To evaluate the predictive value of PTT compared with LAT in PVC ablation.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e We analyzed 310 applications in 54 patients undergoing PVC ablation. PTT and LAT were measured for each application. Acute success was defined as elimination of PVCs without recurrence within 30 minutes. ROC and logistic regression analyses were performed, with location-specific analyses and long-term follow-up.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eAcute success was achieved in 50/54 patients (92.6%). PTT was significantly shorter in successful versus failed applications (median 12s [IQR 8–18] vs 62s [IQR 45–75], p\u0026lt;0.0001). LAT was earlier in successful applications (–36 ms vs –26.5 ms, p\u0026lt;0.01). PTT showed superior predictive accuracy (AUC=0.93) versus LAT (AUC=0.72). A PTT cutoff of 25s yielded 88% sensitivity and 83% specificity. Location-specific analysis showed variability, especially in LV summit cases. In multivariable analysis, both shorter PTT (p\u0026lt;0.001) and earlier LAT (p=0.005) predicted success. Long-term follow-up (18±6 months, n=48) demonstrated 85.4% freedom from recurrence; recurrent cases had longer PTT during index ablation (28.5s vs 11.5s, p=0.008).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e PTT is a practical, real-time predictor of acute PVC ablation success, outperforming LAT. A 25-second cutoff provides objective procedural guidance, though anatomical variations should be considered.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCONDENSED ABSTRACT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe evaluated PVC Termination Time (PTT)—the interval from radiofrequency onset to PVC disappearance—as a predictor of ablation success in 54 patients (310 applications). PTT was significantly shorter in successful versus failed applications (median 12s vs 62s, p\u0026lt;0.0001) and demonstrated superior predictive accuracy (AUC=0.93) compared to local activation time (AUC=0.72). A 25-second PTT cutoff provided 88% sensitivity and 83% specificity. Location-specific PTT showed variations, with LV summit demonstrating wider variability (IQR 5-38s). PTT offers a practical, real-time metric for guiding PVC ablation procedures, potentially improving efficiency and outcomes.\u003c/p\u003e","manuscriptTitle":"PVC Termination Time: A Novel Real-Time Predictor of Ablation Success","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-10 14:39:16","doi":"10.21203/rs.3.rs-7698543/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"29ac9f02-dd98-49be-b558-d6a9cd7da898","owner":[],"postedDate":"October 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-12-15T16:01:29+00:00","versionOfRecord":{"articleIdentity":"rs-7698543","link":"https://doi.org/10.1007/s10840-025-02189-3","journal":{"identity":"journal-of-interventional-cardiac-electrophysiology","isVorOnly":false,"title":"Journal of Interventional Cardiac Electrophysiology"},"publishedOn":"2025-12-09 15:57:36","publishedOnDateReadable":"December 9th, 2025"},"versionCreatedAt":"2025-10-10 14:39:16","video":"","vorDoi":"10.1007/s10840-025-02189-3","vorDoiUrl":"https://doi.org/10.1007/s10840-025-02189-3","workflowStages":[]},"version":"v1","identity":"rs-7698543","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7698543","identity":"rs-7698543","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}