Novel Precordial Mid-T-Wave Inversion: A Pulsation Artifact Mimicking Myocardial Ischemia and Proposed Mechanisms

Novel Precordial Mid-T-Wave Inversion: A Pulsation Artifact Mimicking Myocardial Ischemia and Proposed Mechanisms | 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 Case Report Novel Precordial Mid-T-Wave Inversion: A Pulsation Artifact Mimicking Myocardial Ischemia and Proposed Mechanisms Yangyang Ji, Chongkai Liu, Peng Li, Chengyu Wang, Hongxiang Xie, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8074153/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 22 You are reading this latest preprint version Abstract Background : Electrocardiographic (ECG) artifacts mimicking acute coronary syndrome (ACS) pose a significant risk of misdiagnosis and unnecessary invasive procedures. While arterial pulsation artifacts are known to cause limb-lead ST-T changes adhering to the "single-limb lead exemption principle," their potential to induce specific repolarization abnormalities in precordial leads remains unreported. Case presentation: A 66-year-old woman presented with chest tightness. The initial ECG showed ST-segment elevation in leads III and aVF, depression in I and aVL, and a previously undescribed pattern of isolated mid-portion T-wave inversions in precordial leads V2–V6, with preserved initial T-wave morphology. Suspected ACS was reconsidered after a senior physician noted atypical features. The diagnosis of artifact was confirmed after repositioning the limb electrodes, which resulted in complete normalization of all ECG abnormalities. Coronary computed tomography angiography revealed only mild atherosclerosis, ruling out acute ischemia. Conclusion : This case is the first to describe a unique pulsation artifact pattern featuring isolated mid-portion T-wave inversions in precordial leads. We elucidate its mechanism via propagation of limb-derived interference currents through the Wilson Central Terminal, which perturbs the vulnerable mid-repolarization phase. This novel sign, especially when combined with the limb lead exemption principle (spared lead II localizing the source to the left arm), suggests a potential electrocardiographic sign for differentiating artifact from true pathology. We propose a simple diagnostic algorithm integrating lead-specific analysis and dynamic electrode repositioning to prevent misdiagnosis and unnecessary interventions in clinical practice. Electrocardiographic artifact pulsation artifact T-wave inversion myocardial ischemia Wilson Central Terminal misdiagnosis Figures Figure 1 Figure 2 Figure 3 Introduction Electrocardiographic artifacts—waveforms mimicking cardiac pathology but originating from extracardiac sources—pose significant diagnostic challenges in emergency cardiovascular care. While common artifacts (e.g., tremors, electromagnetic interference) are well-documented to cause ST-segment deviations or pseudo-arrhythmias [ 1 – 5 ], their potential to generate localized repolarization abnormalities remains underexplored. Crucially, such artifacts may mimic acute coronary syndrome (ACS), leading to unnecessary interventions including invasive angiography [ 6 – 7 ]. Recent studies highlight that arterial pulsation artifacts can produce limb-lead ST/T changes obeying the "single-limb lead exemption principle" [ 8 – 10 ]. However, no prior reports describe isolated mid-portion T-wave inversions in precordial leads—a novel finding observed in our case. This unique pattern, characterized by preserved initial T-wave morphology with focal mid-portion inversion, expands the spectrum of pulsation-induced artifacts and may serve as a valuable sign for differential diagnosis. Here, we present a case where right radial artery pulsation artifact mimicked ST-elevation myocardial infarction, initially prompting evaluation for ACS. The resolution of both limb-lead ST changes and precordial T-wave mid-portion inversions after electrode repositioning confirmed the artifactual nature, underscoring the imperative for precise artifact recognition. This report: Describes a previously unrecognized T-wave artifact pattern; Elucidates its mechanistic basis via Wilson Central Terminal dynamics; Proposes a diagnostic algorithm integrating lead-specific analysis and repolarization features. Case Presentation A 66-year-old woman presented to our emergency department with a one-hour history of chest tightness. Her medical history included hypertension for 3 years, managed with oral antihypertensive agents, and she reported adequate blood pressure control. Initial vital signs were: Blood Pressure (BP) 130/80 mmHg, Heart Rate (HR) 72 beats per minute (bpm), Respiratory Rate (RR) 22 breaths per minute, Temperature 37°C. Initial laboratory investigations, including troponin, other cardiac biomarkers, liver function, renal function, and electrolytes, were unremarkable. An electrocardiogram (ECG) revealed ST-segment changes (Fig. 1 ). ECG Findings (Fig. 1 ):Sinus rhythm at 75 bpm.ST-segment elevation in limb leads III, aVF, and aVR.ST-segment depression in leads I and aVL.Lead II showed no significant abnormalities.Precordial leads (V2-V6): The initial part of the T-wave appeared normal, but a small T-wave inversion was observed at the mid-portion of the T-wave. Initial Management and Diagnostic Dilemma: The junior emergency physician, considering the patient's age, hypertension history, chest tightness, and the ECG findings, suspected possible Acute Coronary Syndrome (ACS) and recommended invasive coronary angiography. However, the senior emergency physician reviewed the ECG and noted atypical features compared to classic myocardial infarction patterns, raising suspicion of artifact, although the specific source was unclear. A repeat ECG (Fig. 2 ) showed persistent but diminished ST-segment elevation. Cardiology consultation was sought for further evaluation. Cardiology Consultation and Resolution: The consulting cardiologist considered that the ECG abnormalities were likely caused by arterial pulsation artifact. After repositioning the limb electrodes away from the right radial artery pulse, a third ECG was performed(Figure 3 ). This revealed complete resolution of the ST-segment and T-wave abnormalities, showing a normal tracing (ECG not shown, but normalization described). To definitively rule out Non-ST-Elevation Myocardial Infarction (NSTEMI), an emergency Coronary Computed Tomography Angiography(CCTA) was performed, which revealed only mild stenosis in the left anterior descending (LAD) artery. The diagnosis was established as Coronary Artery Atherosclerosis. The patient's symptoms resolved with supportive care. Discussion Electrocardiographic (ECG) artifacts—waveforms mimicking cardiac pathology despite extracardiac origins—present considerable diagnostic challenges in acute cardiovascular settings. Although ST-T changes may indicate true pathological conditions such as acute coronary syndrome, hypertrophic cardiomyopathy, pulmonary embolism, or myocarditis[8-10], technical artifacts stemming from non-ischemic factors can closely simulate these abnormalities, potentially leading to misdiagnosis and unnecessary interventions[6-7]. This case highlights the capacity of arterial pulsation to produce deceptive ECG changes and, importantly, delineates a previously unreported pattern of mid-portion T-wave inversion in precordial leads, which may aid in artifact recognition. 3.1 Origins and Localization of Electrocardiographic Artifacts The accurate identification of ECG artifacts begins with recognizing their sources, which are broadly classified as technical, physiological, or environmental [1-5]. Our case focuses on a physiological source: arterial pulsation artifact. Such artifacts frequently obey the "single-limb lead exemption principle" [3,6-7], which is derived from the Einthoven triangle and Wilson Central Terminal (WCT) theory. This principle provides a vital diagnostic key: A right arm artifact will spare lead III. A left arm artifact will spare lead II. A left leg artifact will spare lead I. Furthermore, interference from a limb electrode does not remain isolated; it can disseminate to the precordial leads because the WCT itself becomes contaminated and serves as the reference for all chest leads (V1-V6) [6]. Applying this framework to our case, the complete sparing of lead II was an pivotal observation. It definitively pointed to the left arm as the source of the artifact, thereby correcting our initial suspicion of the right radial artery. This demonstrates that a systematic approach—first analyzing the ECG for a spared lead to localize the source, followed by physical verification of the electrode—is fundamental to unmasking pulsation artifacts. 3.2 Mid-Portion T-Wave Inversion in Precordial Leads: A Novel Artifactual Pattern The most striking feature was a previously unreported pattern of repolarization artifact: isolated mid-portion T-wave inversions across leads V2–V6. Its signature characteristics—preserved initial T-wave morphology, a shallow focal mid-T notch (<1 mm), and immediate normalization after technical correction—are pivotal for diagnosis. The key distinction from pathological T-wave inversions (e.g., the symmetric depth of Wellns' or the asymmetric breadth of LVH) lies in its dynamic reversibility and precise spatiotemporal specificity. Mechanistically, we posit that pulsation-induced currents from a limb electrode are integrated into the Wilson Central Terminal (WCT). From the WCT, this interference is broadcast to all precordial leads. The reason it manifests solely in the mid-portion of the T-wave is that this segment corresponds to the peak of ventricular repolarization (action potential phase 3). This is a period of well-established electrical vulnerability [11], where the myocardium is most susceptible to extrinsic electrical noise, thus explaining the highly selective nature of this artifact. 3.3 Clinical Implications and a Proposed Diagnostic Framework This case provides three key clinical insights: First, anatomical precision in electrode placement is essential, as minor misplacement near arterial pulsation sites can generate substantial artifacts. Second, dynamic testing through electrode repositioning is highly suggestive of an artifact: complete normalization of ECG changes after adjustment strongly argues against acute ischemia. Third, a composite biomarker significantly improves specificity: the coexistence of limb-lead ST-T changes following the exemption principle along with precordial mid-T-wave inversion provides a highly discriminative signature for pulsation artifacts. Based on these insights, we propose the following structured diagnostic approach for similar scenarios: 1. Perform lead-specific analysis to identify any spared limb lead and localize the potential artifact source; 2. Physically inspect electrode positions, paying particular attention to proximity to arterial pulsation sites; 3. Repeat ECG after systematic electrode repositioning to determine the reversibility of observed abnormalities; 4. If abnormalities persist, proceed with further ischemic evaluation based on clinical presentation and biomarker results. Previous work by Rudic et al. [12] demonstrated that repolarization dynamics can differentiate artifacts from true pathology with high specificity (>90%). The combined signature described here—exemption-consistent limb lead changes plus precordial mid-T inversion—warrants further investigation to validate its discriminative capacity and potential to reduce unnecessary invasive procedures in clinical practice. Conclusion We present the first documented case of a pulsation-induced ECG artifact manifesting as isolated mid-portion T-wave inversions in precordial leads. This unique pattern, characterized by its focal appearance at the peak of repolarization and immediate reversibility upon electrode adjustment, represents a novel electrocardiographic sign with the potential to differentiate artifact from true myocardial ischemia. The integration of the limb lead exemption principle for source localization with the recognition of this precordial sign provides a practical diagnostic combination. We underscore the critical importance of a systematic diagnostic approach that includes lead-specific analysis and dynamic electrode repositioning in clinical practice. Adopting this strategy has the potential to improve diagnostic accuracy, thereby reducing the risk of misdiagnosis and preventing unnecessary, invasive interventions in patients presenting with challenging ECG findings. Abbreviations ACS acute coronary syndrome ECG electrocardiogram HR Heart Rate bpm beats per minute RR Respiratory Rate WCT Wilson Central Terminal NSTEMI Non-ST-Elevation Myocardial Infarction CCTA Coronary Computed Tomography Angiography Declarations Ethics approval and consent to participate This case report was approved by the Ethics Committee of Meishan People's Hospital. Written informed consent was obtained from the patient for publication of this case report and any accompanying images. Consent for publication The patient provided written informed consent for the publication of her clinical details and the electrocardiogram images. Competing interests The authors declare that they have no competing interests. Funding Not applicable. Authors' contributions Yangyang Ji and Chongkai Liu contributed equally to this work. Yangyang Ji and Chongkai Liu were responsible for the conception of the case report, data collection, and drafting the initial manuscript. Peng Li and Chengyu Wang participated in the data analysis and interpretation of the clinical findings. Hongxiang Xie and Yuan Li assisted in the literature review and manuscript revision. Huaisheng Ding, as the corresponding author, supervised the entire study, provided critical revisions for important intellectual content, and approved the final version for submission. All authors read and approved the final manuscript. Data availability No datasets were generated or analysed during the current study. 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An electrocardiographic artifact synchronized with the cardiac rhythm: a case report. Ann Intern Med. 2022;175(3):456-458. doi:10.7326/L21-0660. Huang CY, Shan DE, Lai CH, Kuo TBJ, Yang CCH. An accurate electrocardiographic algorithm for differentiation of tremor-induced pseudo-ventricular tachycardia and true ventricular tachycardia. Int J Cardiol. 2006;111(1):163-165. doi:10.1016/j.ijcard.2005.06.017. Thygesen K, Alpert JS, Jaffe AS, Chaitman BR, Bax JJ, Morrow DA, et al. Fourth Universal Definition of Myocardial Infarction (2018). Circulation. 2018;138(13):e618-e651. doi:10.1161/CIR.0000000000000617. Gersh BJ, Maron BJ, Bonow RO, Dearani JA, Fifer MA, Link MS, et al. 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy. J Am Coll Cardiol. 2011;58(25):e212-e260. doi:10.1016/j.jacc.2011.06.011. Konstantinides SV, Meyer G, Becattini C, Bueno H, Geersing GJ, Harjola VP, et al. 2019 ESC guidelines for the diagnosis and management of acute pulmonary embolism. Eur Heart J. 2020;41(4):543-603. doi:10.1093/eurheartj/ehz405. Surawicz B, Childers R, Deal BJ, Gettes LS. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances. J Am Coll Cardiol. 2009;53(11):976-981. doi:10.1016/j.jacc.2008.12.013. Wagner GS, Macfarlane P, Wellens H, Josephson M, Gorgels A, Mirvis DM, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part VI: acute ischemia/infarction. J Am Coll Cardiol. 2009;53(11):1003-1011. doi:10.1016/j.jacc.2008.12.016. Rudic B, Tülümen E, Liebe V, Schrickel JW, Quick S, Borggrefe M, et al. Cardiac repolarization dynamics in artifact detection: a novel algorithm for ECG noise discrimination. Ann Noninvasive Electrocardiol. 2020;25(3):e12721. doi:10.1111/anec.12721. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 22 Apr, 2026 Reviews received at journal 26 Dec, 2025 Reviews received at journal 25 Dec, 2025 Reviews received at journal 25 Dec, 2025 Reviews received at journal 23 Dec, 2025 Reviews received at journal 21 Dec, 2025 Reviewers agreed at journal 21 Dec, 2025 Reviewers agreed at journal 20 Dec, 2025 Reviews received at journal 20 Dec, 2025 Reviewers agreed at journal 20 Dec, 2025 Reviewers agreed at journal 19 Dec, 2025 Reviews received at journal 19 Dec, 2025 Reviews received at journal 18 Dec, 2025 Reviewers agreed at journal 18 Dec, 2025 Reviewers agreed at journal 18 Dec, 2025 Reviewers agreed at journal 18 Dec, 2025 Reviewers agreed at journal 18 Dec, 2025 Reviewers invited by journal 18 Dec, 2025 Editor invited by journal 26 Nov, 2025 Editor assigned by journal 19 Nov, 2025 Submission checks completed at journal 16 Nov, 2025 First submitted to journal 16 Nov, 2025 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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16:06:34","extension":"html","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":56050,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8074153/v1/4e9285c792eae51d9ebdd09a.html"},{"id":99307353,"identity":"15a4b889-83c1-4add-ad9f-6588b9b33386","added_by":"auto","created_at":"2025-12-31 16:06:04","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":3311874,"visible":true,"origin":"","legend":"\u003cp\u003eInitial ECG showing ST-segment elevation in leads III, aVF, and aVR (red arrows), and isolated mid-portion T-wave inversions in precordial leads V2–V6 (black arrows).\u003c/p\u003e","description":"","filename":"figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8074153/v1/3673f9a020ae05f505ab3485.jpg"},{"id":99307655,"identity":"6aa1e7bf-c920-49d1-a020-4a76eaaad18f","added_by":"auto","created_at":"2025-12-31 16:06:29","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":4068840,"visible":true,"origin":"","legend":"\u003cp\u003eRepeat ECG after initial electrode adjustment demonstrates persistent but diminished ST-segment elevation and mid-T inversions.\u003c/p\u003e","description":"","filename":"figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8074153/v1/280b0ccdc5983429ec80d112.jpg"},{"id":99307744,"identity":"ba12bb9a-bae3-4525-a929-935f57848d64","added_by":"auto","created_at":"2025-12-31 16:06:41","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":18601918,"visible":true,"origin":"","legend":"\u003cp\u003eECG after systematic limb electrode repositioning reveals normalization of ST segments and T waves.\u003c/p\u003e","description":"","filename":"figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8074153/v1/5f02b05c94b99e1a0bd06671.jpg"},{"id":99788085,"identity":"6b28e997-8079-4fb6-bbb0-dcefe9a2aaa1","added_by":"auto","created_at":"2026-01-08 12:44:31","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":26291247,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8074153/v1/5f55c6e8-2a81-4749-942e-52fb536e5ee3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Novel Precordial Mid-T-Wave Inversion: A Pulsation Artifact Mimicking Myocardial Ischemia and Proposed Mechanisms","fulltext":[{"header":"Introduction","content":"\u003cp\u003eElectrocardiographic artifacts\u0026mdash;waveforms mimicking cardiac pathology but originating from extracardiac sources\u0026mdash;pose significant diagnostic challenges in emergency cardiovascular care. While common artifacts (e.g., tremors, electromagnetic interference) are well-documented to cause ST-segment deviations or pseudo-arrhythmias [\u003cspan additionalcitationids=\"CR2 CR3 CR4\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], their potential to generate localized repolarization abnormalities remains underexplored. Crucially, such artifacts may mimic acute coronary syndrome (ACS), leading to unnecessary interventions including invasive angiography [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eRecent studies highlight that arterial pulsation artifacts can produce limb-lead ST/T changes obeying the \"single-limb lead exemption principle\" [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. However, no prior reports describe isolated mid-portion T-wave inversions in precordial leads\u0026mdash;a novel finding observed in our case. This unique pattern, characterized by preserved initial T-wave morphology with focal mid-portion inversion, expands the spectrum of pulsation-induced artifacts and may serve as a valuable sign for differential diagnosis.\u003c/p\u003e \u003cp\u003eHere, we present a case where right radial artery pulsation artifact mimicked ST-elevation myocardial infarction, initially prompting evaluation for ACS. The resolution of both limb-lead ST changes and precordial T-wave mid-portion inversions after electrode repositioning confirmed the artifactual nature, underscoring the imperative for precise artifact recognition. This report:\u003c/p\u003e \u003cp\u003eDescribes a previously unrecognized T-wave artifact pattern;\u003c/p\u003e \u003cp\u003eElucidates its mechanistic basis via Wilson Central Terminal dynamics;\u003c/p\u003e \u003cp\u003eProposes a diagnostic algorithm integrating lead-specific analysis and repolarization features.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 66-year-old woman presented to our emergency department with a one-hour history of chest tightness. Her medical history included hypertension for 3 years, managed with oral antihypertensive agents, and she reported adequate blood pressure control. Initial vital signs were: Blood Pressure (BP) 130/80 mmHg, Heart Rate (HR) 72 beats per minute (bpm), Respiratory Rate (RR) 22 breaths per minute, Temperature 37\u0026deg;C. Initial laboratory investigations, including troponin, other cardiac biomarkers, liver function, renal function, and electrolytes, were unremarkable. An electrocardiogram (ECG) revealed ST-segment changes (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eECG Findings (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e):Sinus rhythm at 75 bpm.ST-segment elevation in limb leads III, aVF, and aVR.ST-segment depression in leads I and aVL.Lead II showed no significant abnormalities.Precordial leads (V2-V6): The initial part of the T-wave appeared normal, but a small T-wave inversion was observed at the mid-portion of the T-wave.\u003c/p\u003e \u003cp\u003eInitial Management and Diagnostic Dilemma:\u003c/p\u003e \u003cp\u003eThe junior emergency physician, considering the patient's age, hypertension history, chest tightness, and the ECG findings, suspected possible Acute Coronary Syndrome (ACS) and recommended invasive coronary angiography. However, the senior emergency physician reviewed the ECG and noted atypical features compared to classic myocardial infarction patterns, raising suspicion of artifact, although the specific source was unclear. A repeat ECG (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e) showed persistent but diminished ST-segment elevation. Cardiology consultation was sought for further evaluation.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eCardiology Consultation and Resolution:\u003c/p\u003e \u003cp\u003eThe consulting cardiologist considered that the ECG abnormalities were likely caused by arterial pulsation artifact. After repositioning the limb electrodes away from the right radial artery pulse, a third ECG was performed(Figure \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). This revealed complete resolution of the ST-segment and T-wave abnormalities, showing a normal tracing (ECG not shown, but normalization described). To definitively rule out Non-ST-Elevation Myocardial Infarction (NSTEMI), an emergency Coronary Computed Tomography Angiography(CCTA) was performed, which revealed only mild stenosis in the left anterior descending (LAD) artery. The diagnosis was established as Coronary Artery Atherosclerosis. The patient's symptoms resolved with supportive care.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eElectrocardiographic (ECG) artifacts\u0026mdash;waveforms mimicking cardiac pathology despite extracardiac origins\u0026mdash;present considerable diagnostic challenges in acute cardiovascular settings. Although ST-T changes may indicate true pathological conditions such as acute coronary syndrome, hypertrophic cardiomyopathy, pulmonary embolism, or myocarditis[8-10], technical artifacts stemming from non-ischemic factors can closely simulate these abnormalities, potentially leading to misdiagnosis and unnecessary interventions[6-7]. This case highlights the capacity of arterial pulsation to produce deceptive ECG changes and, importantly, delineates a previously unreported pattern of mid-portion T-wave inversion in precordial leads, which may aid in artifact recognition.\u003c/p\u003e\n\u003cp\u003e3.1 Origins and Localization of Electrocardiographic Artifacts\u003c/p\u003e\n\u003cp\u003eThe accurate identification of ECG artifacts begins with recognizing their sources, which are broadly classified as technical, physiological, or environmental [1-5]. Our case focuses on a physiological source:\u0026nbsp;arterial pulsation artifact. Such artifacts frequently obey the\u0026nbsp;\u0026quot;single-limb lead exemption principle\u0026quot;\u0026nbsp;[3,6-7], which is derived from the Einthoven triangle and Wilson Central Terminal (WCT) theory. This principle provides a vital diagnostic key:\u003c/p\u003e\n\u003cp\u003eA\u0026nbsp;right arm\u0026nbsp;artifact will spare lead III.\u003c/p\u003e\n\u003cp\u003eA\u0026nbsp;left arm\u0026nbsp;artifact will spare lead II.\u003c/p\u003e\n\u003cp\u003eA\u0026nbsp;left leg\u0026nbsp;artifact will spare lead I.\u003c/p\u003e\n\u003cp\u003eFurthermore, interference from a limb electrode does not remain isolated; it can disseminate to the precordial leads because the WCT itself becomes contaminated and serves as the reference for all chest leads (V1-V6) [6].\u003c/p\u003e\n\u003cp\u003eApplying this framework to our case, the complete sparing of lead II was an pivotal observation. It definitively pointed to the left arm as the source of the artifact, thereby correcting our initial suspicion of the right radial artery. This demonstrates that a systematic approach\u0026mdash;first analyzing the ECG for a spared lead to localize the source, followed by physical verification of the electrode\u0026mdash;is fundamental to unmasking pulsation artifacts.\u003c/p\u003e\n\u003cp\u003e3.2 Mid-Portion T-Wave Inversion in Precordial Leads: A Novel Artifactual Pattern\u003c/p\u003e\n\u003cp\u003eThe most striking feature was a previously unreported pattern of repolarization artifact: isolated mid-portion T-wave inversions across leads V2\u0026ndash;V6. Its signature characteristics\u0026mdash;preserved initial T-wave morphology, a shallow focal mid-T notch (\u0026lt;1 mm), and immediate normalization after technical correction\u0026mdash;are pivotal for diagnosis. The key distinction from pathological T-wave inversions (e.g., the symmetric depth of Wellns\u0026apos; or the asymmetric breadth of LVH) lies in its dynamic reversibility and precise spatiotemporal specificity.\u003c/p\u003e\n\u003cp\u003eMechanistically, we posit that pulsation-induced currents from a limb electrode are integrated into the Wilson Central Terminal (WCT). From the WCT, this interference is broadcast to all precordial leads. The reason it manifests solely in the mid-portion of the T-wave is that this segment corresponds to the peak of ventricular repolarization (action potential phase 3). This is a period of well-established electrical vulnerability [11], where the myocardium is most susceptible to extrinsic electrical noise, thus explaining the highly selective nature of this artifact.\u003c/p\u003e\n\u003cp\u003e3.3 Clinical Implications and a Proposed Diagnostic Framework\u003c/p\u003e\n\u003cp\u003eThis case provides three key clinical insights:\u003c/p\u003e\n\u003cp\u003eFirst, anatomical precision in electrode placement is essential, as minor misplacement near arterial pulsation sites can generate substantial artifacts.\u003c/p\u003e\n\u003cp\u003eSecond, dynamic testing through electrode repositioning is highly suggestive of an artifact: complete normalization of ECG changes after adjustment strongly argues against acute ischemia.\u003c/p\u003e\n\u003cp\u003eThird, a composite biomarker significantly improves specificity: the coexistence of limb-lead ST-T changes following the exemption principle along with precordial mid-T-wave inversion provides a highly discriminative signature for pulsation artifacts.\u003c/p\u003e\n\u003cp\u003eBased on these insights, we propose the following structured diagnostic approach for similar scenarios:\u003c/p\u003e\n\u003cp\u003e1. Perform lead-specific analysis to identify any spared limb lead and localize the potential artifact source;\u003c/p\u003e\n\u003cp\u003e2. Physically inspect electrode positions, paying particular attention to proximity to arterial pulsation sites;\u003c/p\u003e\n\u003cp\u003e3. Repeat ECG after systematic electrode repositioning to determine the reversibility of observed abnormalities;\u003c/p\u003e\n\u003cp\u003e4. If abnormalities persist, proceed with further ischemic evaluation based on clinical presentation and biomarker results.\u003c/p\u003e\n\u003cp\u003ePrevious work by Rudic et al. [12] demonstrated that repolarization dynamics can differentiate artifacts from true pathology with high specificity (\u0026gt;90%). The combined signature described here\u0026mdash;exemption-consistent limb lead changes plus precordial mid-T inversion\u0026mdash;warrants further investigation to validate its discriminative capacity and potential to reduce unnecessary invasive procedures in clinical practice.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eWe present the first documented case of a pulsation-induced ECG artifact manifesting as isolated mid-portion T-wave inversions in precordial leads. This unique pattern, characterized by its focal appearance at the peak of repolarization and immediate reversibility upon electrode adjustment, represents a novel electrocardiographic sign with the potential to differentiate artifact from true myocardial ischemia. The integration of the limb lead exemption principle for source localization with the recognition of this precordial sign provides a practical diagnostic combination. We underscore the critical importance of a systematic diagnostic approach that includes lead-specific analysis and dynamic electrode repositioning in clinical practice. Adopting this strategy has the potential to improve diagnostic accuracy, thereby reducing the risk of misdiagnosis and preventing unnecessary, invasive interventions in patients presenting with challenging ECG findings.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eACS acute coronary syndrome \u003c/p\u003e\n\u003cp\u003eECG electrocardiogram\u003c/p\u003e\n\u003cp\u003eHR Heart Rate \u003c/p\u003e\n\u003cp\u003ebpm beats per minute \u003c/p\u003e\n\u003cp\u003eRR Respiratory Rate \u003c/p\u003e\n\u003cp\u003eWCT Wilson Central Terminal \u003c/p\u003e\n\u003cp\u003eNSTEMI Non-ST-Elevation Myocardial Infarction \u003c/p\u003e\n\u003cp\u003eCCTA Coronary Computed Tomography Angiography\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eThis case report was approved by the Ethics Committee of Meishan People\u0026apos;s Hospital. Written informed consent was obtained from the patient for publication of this case report and any accompanying images.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eThe patient provided written informed consent for the publication of her clinical details and the electrocardiogram images.\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eAuthors\u0026apos; contributions\u003c/p\u003e\n\u003cp\u003eYangyang Ji and Chongkai Liu contributed equally to this work. Yangyang Ji and Chongkai Liu were responsible for the conception of the case report, data collection, and drafting the initial manuscript. Peng Li and Chengyu Wang participated in the data analysis and interpretation of the clinical findings. Hongxiang Xie and Yuan Li assisted in the literature review and manuscript revision. Huaisheng Ding, as the corresponding author, supervised the entire study, provided critical revisions for important intellectual content, and approved the final version for submission. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003eData availability\u003c/p\u003e\n\u003cp\u003eNo datasets were generated or analysed during the current study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eGregg RE, Zhou SH, Lindauer JM, Helfenbein ED, Giuliano KK. What is inside the electrocardiograph? J Electrocardiol. 2008;41(1):8-14.doi:10.1016/j.jelectrocard.2007.08.059.\u003c/li\u003e\n\u003cli\u003eZhai HL, Zheng B, Zhai GL. Is a shaking hand or a trembling heart producing changes in electrocardiogram findings? JAMA Intern Med. 2022;182(7):772-773. doi:10.1001/jamainternmed.2022.1796.\u003c/li\u003e\n\u003cli\u003eKnight BP, Pelosi F, Michaud GF, Strickberger SA, Morady F. Clinical consequences of electrocardiographic artifact mimicking ventricular tachycardia. N Engl J Med. 1999;341(17):1270-1274.doi:10.1056/NEJM199910213411704.\u003c/li\u003e\n\u003cli\u003eDuan H, Zhang CH. A series of abnormal ECGs: are they benign or sinister? Circulation. 2023;147(17):1407-1410. doi:10.1161/CIRCULATIONAHA.123.064375.\u003c/li\u003e\n\u003cli\u003eAslanger E. An unusual electrocardiogram artifact in a patient with near syncope. J Electrocardiol. 2010;43(6):686-688. doi:10.1016/j.jelectrocard.2010.04.012.\u003c/li\u003e\n\u003cli\u003eLi C, Chang Q, Yu L, Liu R. An electrocardiographic artifact synchronized with the cardiac rhythm: a case report. Ann Intern Med. 2022;175(3):456-458. doi:10.7326/L21-0660.\u003c/li\u003e\n\u003cli\u003eHuang CY, Shan DE, Lai CH, Kuo TBJ, Yang CCH. An accurate electrocardiographic algorithm for differentiation of tremor-induced pseudo-ventricular tachycardia and true ventricular tachycardia. Int J Cardiol. 2006;111(1):163-165. doi:10.1016/j.ijcard.2005.06.017.\u003c/li\u003e\n\u003cli\u003eThygesen K, Alpert JS, Jaffe AS, Chaitman BR, Bax JJ, Morrow DA, et al. Fourth Universal Definition of Myocardial Infarction (2018). Circulation. 2018;138(13):e618-e651. doi:10.1161/CIR.0000000000000617.\u003c/li\u003e\n\u003cli\u003eGersh BJ, Maron BJ, Bonow RO, Dearani JA, Fifer MA, Link MS, et al. 2011 ACCF/AHA guideline for the diagnosis and treatment of hypertrophic cardiomyopathy. J Am Coll Cardiol. 2011;58(25):e212-e260. doi:10.1016/j.jacc.2011.06.011.\u003c/li\u003e\n\u003cli\u003eKonstantinides SV, Meyer G, Becattini C, Bueno H, Geersing GJ, Harjola VP, et al. 2019 ESC guidelines for the diagnosis and management of acute pulmonary embolism. Eur Heart J. 2020;41(4):543-603. doi:10.1093/eurheartj/ehz405.\u003c/li\u003e\n\u003cli\u003eSurawicz B, Childers R, Deal BJ, Gettes LS. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances. J Am Coll Cardiol. 2009;53(11):976-981. doi:10.1016/j.jacc.2008.12.013.\u003c/li\u003e\n\u003cli\u003eWagner GS, Macfarlane P, Wellens H, Josephson M, Gorgels A, Mirvis DM, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part VI: acute ischemia/infarction. J Am Coll Cardiol. 2009;53(11):1003-1011. doi:10.1016/j.jacc.2008.12.016.\u003c/li\u003e\n\u003cli\u003eRudic B, T\u0026uuml;l\u0026uuml;men E, Liebe V, Schrickel JW, Quick S, Borggrefe M, et al. Cardiac repolarization dynamics in artifact detection: a novel algorithm for ECG noise discrimination. Ann Noninvasive Electrocardiol. 2020;25(3):e12721. doi:10.1111/anec.12721.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-cardiovascular-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcar","sideBox":"Learn more about [BMC Cardiovascular Disorders](http://bmccardiovascdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcar/default.aspx","title":"BMC Cardiovascular Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Electrocardiographic artifact, pulsation artifact, T-wave inversion, myocardial ischemia, Wilson Central Terminal, misdiagnosis","lastPublishedDoi":"10.21203/rs.3.rs-8074153/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8074153/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e: Electrocardiographic (ECG) artifacts mimicking acute coronary syndrome (ACS) pose a significant risk of misdiagnosis and unnecessary invasive procedures. While arterial pulsation artifacts are known to cause limb-lead ST-T changes adhering to the \"single-limb lead exemption principle,\" their potential to induce specific repolarization abnormalities in precordial leads remains unreported.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase presentation: \u003c/strong\u003eA 66-year-old woman presented with chest tightness. The initial ECG showed ST-segment elevation in leads III and aVF, depression in I and aVL, and a previously undescribed pattern of isolated mid-portion T-wave inversions in precordial leads V2–V6, with preserved initial T-wave morphology. Suspected ACS was reconsidered after a senior physician noted atypical features. The diagnosis of artifact was confirmed after repositioning the limb electrodes, which resulted in complete normalization of all ECG abnormalities. Coronary computed tomography angiography revealed only mild atherosclerosis, ruling out acute ischemia.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion\u003c/strong\u003e: This case is the first to describe a unique pulsation artifact pattern featuring isolated mid-portion T-wave inversions in precordial leads. We elucidate its mechanism via propagation of limb-derived interference currents through the Wilson Central Terminal, which perturbs the vulnerable mid-repolarization phase. This novel sign, especially when combined with the limb lead exemption principle (spared lead II localizing the source to the left arm), suggests a potential electrocardiographic sign for differentiating artifact from true pathology. We propose a simple diagnostic algorithm integrating lead-specific analysis and dynamic electrode repositioning to prevent misdiagnosis and unnecessary interventions in clinical practice.\u003c/p\u003e","manuscriptTitle":"Novel Precordial Mid-T-Wave Inversion: A Pulsation Artifact Mimicking Myocardial Ischemia and Proposed Mechanisms","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-22 17:17:32","doi":"10.21203/rs.3.rs-8074153/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-04-22T11:57:53+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-26T22:09:28+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-26T04:47:34+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-25T20:14:20+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-23T07:26:40+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-21T16:10:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"121469848340278705262998471308769989216","date":"2025-12-21T15:58:26+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"118664000964678610657847004888557604404","date":"2025-12-21T01:52:19+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-20T18:22:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"156279115141071752483903452520705464650","date":"2025-12-20T13:46:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"150437113742583581746832845725757945744","date":"2025-12-19T23:35:40+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-19T09:55:54+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-18T16:22:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"168628214290832190404287611557677491884","date":"2025-12-18T15:43:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"176621122904193741631179098888766952821","date":"2025-12-18T13:31:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"307804715693766574362680504021718938688","date":"2025-12-18T12:04:44+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"226320526508908806030288739132067565623","date":"2025-12-18T11:38:45+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-12-18T11:29:28+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-11-26T10:07:10+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-19T10:27:44+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-16T15:43:05+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Cardiovascular Disorders","date":"2025-11-16T15:40:31+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-cardiovascular-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcar","sideBox":"Learn more about [BMC Cardiovascular Disorders](http://bmccardiovascdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcar/default.aspx","title":"BMC Cardiovascular Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"13b76a55-b0de-4307-b194-c5caad32d7ea","owner":[],"postedDate":"December 22nd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-05-18T12:40:09+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-22 17:17:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8074153","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8074153","identity":"rs-8074153","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}