Toddler cavotricuspid valve isthmus ablation for typical atrial flutter with cryoablation

Toddler cavotricuspid valve isthmus ablation for typical atrial flutter with cryoablation | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL This is a preprint and has not been peer reviewed. Data may be preliminary. 21 March 2025 V1 Latest version Share on Toddler cavotricuspid valve isthmus ablation for typical atrial flutter with cryoablation Authors : Mohammad Ebrahim A [email protected] , Mohamed Abdelnaby A , and Phil Saul 0000-0001-7582-677X Authors Info & Affiliations https://doi.org/10.22541/au.174252797.73060935/v1 177 views 86 downloads Contents Abstract Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Case presentation: We describe the youngest successful cavotricupsid isthmus cryoablation in a toddler with small atrial septal defect whose medical management was complicated with intrinsic conduction disease and recurrent atrial flutter. Methods: Zero fluoroscopy electrophysiology study performed. Cavotricuspid isthmus proved to be “in” circuit with entrainment. Line of block was achieved with termination of atrial flutter using 2 minutes cryo-lesions. Results: The patient underwent successful cryoablation at 9 kg, without recurrence. Conclusion: Cavotricuspid isthmus ablation using cryoablation resulted in no recurrence of atrial flutter for at least 1 year of follow up. Ablation offers a less invasive approach (versus pacemaker implantation) for toddlers with coexisting conduction disease, limiting medical management option. Toddler cavotricuspid valve isthmus ablation for typical atrial flutter with cryoablation Authors: Mohammad A Ebrahim | Department of Pediatrics, Kuwait University Faculty of Medicine, affiliated with Chest Diseases Hospital, Kuwait | [email protected] Hasan Majid | Kuwait University Faculty of Medicine | [email protected] Mohamed A Abdelnaby | Department of Pediatric Cardiology, Chest Diseases Hospital, Ministry of Health, Kuwait | [email protected] J. Philip Saul, MD | Professor of Pediatrics, West Virginia University School of Medicine | [email protected] Corresponding Author: Mohammad A Ebrahim, MD [email protected] or [email protected] Phone: +965 90977894 ; + 965 25319486 Address: Jabriya, Block 4, Street 102, Postal Office 46300 Disclosures: None No conflicts of interest Abstract Case presentation: We describe the youngest successful cavotricupsid isthmus cryoablation in a toddler with small atrial septal defect whose medical management was complicated with intrinsic conduction disease and recurrent atrial flutter. Methods: Zero fluoroscopy electrophysiology study performed. Cavotricuspid isthmus proved to be “in” circuit with entrainment. Line of block was achieved with termination of atrial flutter using 2 minutes cryo-lesions. Results: The patient underwent successful cryoablation at 9 kg, without recurrence. Conclusion: Cavotricuspid isthmus ablation using cryoablation resulted in no recurrence of atrial flutter for at least 1 year of follow up. Ablation offers a less invasive approach (versus pacemaker implantation) for toddlers with coexisting conduction disease, limiting medical management option. Keywords: Atrial flutter, sinus node dysfunction, AV block, cryoablation Case presentation A 16-month-old child with no past medical history, referred for bradycardia. She was clinically asymptomatic except for poor growth consistent with weight and height below the third percentiles. Her ECG (Figure 1A) revealed left axis deviation, normal PR interval but with significant bradycardia indicative of sinus node dysfunction (SND). Her echo revealed a small ASD but was otherwise normal. Surprisingly, the Holter (Figure 1B) showed persistent atrial flutter (AFL), with variable degrees of block (2:1 – 6:1) and heart rates (HR) between 53-150 beats per minute (bpm). The average HR was 92 bpm despite being not on any atrioventricular nodal (AVN) blocking agent, raising concerns for intrinsic AVN dysfunction. The patient was admitted (Figure 2) for TEE to rule out intracardiac thrombi and subsequent cardioversion. She was successfully reverted to sinus rhythm, but remained bradycardic, and was started on low-dose Sotalol, at 1 mg/kg/ day, given the intrinsic conduction disease. Maternal ECG was normal, but a paternal one could not be obtained, and genetic testing was refused. Family history was otherwise unremarkable. Two months later, a follow-up Holter revealed counterclockwise AFL for which she was admitted and again cardioverted successfully. Sotalol was increased to 1.5 mg/kg/day. Over the next four months, two follow-up Holter ECGs (Figure 3) showed junctional and ventricular escape rhythms with rare sinus capture beats. Two months later, the patient came back with AFL and was successfully cardioverted (Figure 4) . The family was offered pacemaker or ablation but refused. At this point, the dose of Sotalol was increased to 2 mg/kg/day. One month later, the patient returned with persistent AFL, was successfully cardioverted, and agreed for ablation. Zero fluoroscopy, two catheter electrophysiology study (EPS) was performed using 7F Freezor™ Xtra cardiac cryoablation catheter (217F1 – 49 mm), at age 2 years and 10 months (9 kg). The EPS demonstrated cavotricupsid isthmus based typical AFL (proved with entrainment), and cryoablation of the isthmus resulted in termination of AFL (one application for 2 minutes per location, point by point across cavotricuspid isthmus). After ablation and while being off sotalol, the rhythm was predominantly junctional rhythm, but no recurrence of flutter was observed over the subsequent 12 months. The patient is now almost 4 years old. Figure 1. At the time of presentation. Figure 2. On the first admission. The ECG reveals positive sawtooth-like F waves in the inferior leads consistent with clockwise CTI-dependent AFL at 4:1 conduction. This was cardioverted to bradycardic sinus rhythm. Figures 3A&3B. These were recorded after Sotalol dose was increased after the second cardioversion. (3A). ECG reveals sinus pause at 974 msec, followed by re-emergence of SAN activity, but after 935 msec, the P-wave is seen marching on the QRS indicative of sinus bradycardia and junctional escape in the form of isorhythmic AV dissociation. Later sinus rhythm resumes intermittently. (3B). The QRS complexes here are relatively wider, indicating a ventricular escape origin. The third QRS is narrow and preceded immediately by a sinus beat, thus, this QRS represents a sinus capture beat. Figure 4. During the third admission after cardioversion. In this ECG, the first beat is not preceded by any atrial activity and is junctional. The second beat is a conducted retrograde P wave. The third beat appears wider, seen obviously on lead II indicating a ventricular escape origin. This beat was followed by a retrograde P-wave, best seen in lead III, which was conducted downward to the ventricles producing a narrow QRS complex similar to the first two beats. This QRS is described as capture-echo beat. This phenomenon occurred in the sixth and eighth beats, which were comparatively wider indicating conduction aberrancy. The thirteenth beat is another atrial capture beat. Discussion Atrial tachyarrhythmia (AT), including AFL, has frequently been reported to coexist with sinus node dysfunction (SND). 1 The bradycardia in SND increases the probability of atrial ectopy due to loss of the protective overdrive suppression over the potential subsidiary pacemaker cells. 1 On the other hand, prolonged or frequent episodes of AT have been reported to produce structural alterations that sustain the AT, including apoptosis and fibrosis, which electrically decouple the anastomosing cardiomyocytes. 1 Concomitant electric remodeling may downregulate the inward calcium current and enhance inward rectifier potassium currents, resulting in shortened refractoriness which sustains the reentrant circuit. 1 Defective intracellular calcium handling can also lead to increased diastolic intracellular calcium concentrations and increased risk of ectopy. 1 In some cases, one factor causes or complicates the other by atrial electroanatomic and electrophysiologic remodeling, while in others, a primary atrial cardiomyopathy or inherited channelopathy produces both SND and atrial tachydysrhythmia. 1 Specifically, mutations in the SCN5A, GNB5 and the HCN genes are known to cause SND. 2-4 Furthermore, loss-of-function mutation in NKX2-5 has been associated with secundum ASDs and SAN/AVN conduction defects. 5,6 Otherwise, SND can be associated with complex congenital heart disease or subsequent to cardiac surgery. Due to the young age of presentation, this case is likely due to a genetic mutation which could not be documented because of the parents declining the evaluation. An NKX2-5 mutation could account for all the observed findings. Conversion to and maintenance of NSR in patients with AFL is preferable to a rate-control strategy since it relieves the patient’s symptoms, improves the functionality, lowers risk of tachycardia-induced cardiomyopathy, and reduces the risk of systemic thromboembolic events attributable to the AFL. In patients with concurrent SND, pharmacologic cardioversion is limited by worsening of preexisting SND. Hence, pacing with proper medication dosing or ablation options are useful and were both presented to the family. Normalizing HR through pacing may inhibit AFL development and allow for appropriate dosing of medications. However, given the age of the patient, an epicardial pacemaker would have been the most appropriate option, requiring a surgical approach. Hence, the family elected for ablation to prevent AFL development and to monitor the HR off medications. Pacing for SND is the only effective modality when symptomatic and all the reversible causes are excluded, but our patient had concurrent AFL. 1 Given the size and age of the patient, cryoablation was thought to be the safest approach for this patient and perhaps less risk for coronary artery injury compared to radiofrequency approach. 7 Cryo-lesions are well-defined fibrotic lesions that do not disrupt the ultrastructure of collagen, thus, cryoablation is less likely to damage or cause persistent luminal stenosis of the adjacent blood vessels. 8 In conclusion, cavotricuspid isthmus ablation using cryoablation resulted in no recurrence of atrial flutter for at least 1 year of follow up without complications. Ablation offer a less invasive approach (versus pacemaker implantation) to toddlers with coexisting conduction disease, limiting medical management option. The treatment allowed for withdrawal of anti-arrhythmic medication and avoidance of pacing. Patient continued to be asymptomatic on follow-up with normal cardiac function. References 1. John, R. M., & Kumar, S. (2016). Sinus node and atrial arrhythmias. Circulation, 133(19), 1892–1900. https://doi.org/10.1161/circulationaha.116.018011. 2. Adsit, G. S. (2013). Channelopathies from mutations in the cardiac sodium channel protein complex. Journal of Molecular and Cellular Cardiology , 61 , 34–43. https://doi.org/10.1016/j.yjmcc.2013.03.017. 3. Lodder, E. M. (2016). GNB5 Mutations Cause an Autosomal-Recessive Multisystem Syndrome with Sinus Bradycardia and Cognitive Disability. The American Journal of Human Genetics , 99 (3), 704–710. https://doi.org/10.1016/j.ajhg.2016.06.025. 4. Duhme, N. (2012). Altered HCN4 channel C-linker interaction is associated with familial tachycardia–bradycardia syndrome and atrial fibrillation. European Heart Journal , 34 (35), 2768–2775. https://doi.org/10.1093/eurheartj/ehs391. 5. Gutierrez-Roelens, I. (2006). A novel CSX/NKX2-5 mutation causes autosomal-dominant AV block: are atrial fibrillation and syncopes part of the phenotype? European Journal of Human Genetics , 14 (12), 1313–1316. https://doi.org/10.1038/sj.ejhg.5201702. 6. Rozqie, R., & Satwiko, M. G. (2021). A novel NKX2–5 double variant corresponds with familial atrial septal defect with arrhythmia in Indonesia. European Heart Journal , 42 (Supplement_1). https://doi.org/10.1093/eurheartj/ehab724.2517. 7. Walsh, M. A., & Gonzalez, C. M. (2021). Outcomes from pediatric ablation. JACC. Clinical Electrophysiology , 7 (11), 1358–1365. https://doi.org/10.1016/j.jacep.2021.03.012. 8. Issa, Z. F., Miller, J. M., & Zipes, D. P. (2019). Ablation energy sources. In Elsevier eBooks (pp. 206–237). https://doi.org/10.1016/b978-0-323-52356-1.00007-4. Information & Authors Information Version history V1 Version 1 21 March 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Authors Affiliations Mohammad Ebrahim A [email protected] Kuwait University Faculty of Medicine View all articles by this author Mohamed Abdelnaby A Chest Diseases Hospital View all articles by this author Phil Saul 0000-0001-7582-677X West Virginia University School of Medicine View all articles by this author Metrics & Citations Metrics Article Usage 177 views 86 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Mohammad Ebrahim A, Mohamed Abdelnaby A, Phil Saul. Toddler cavotricuspid valve isthmus ablation for typical atrial flutter with cryoablation. Authorea . 21 March 2025. DOI: https://doi.org/10.22541/au.174252797.73060935/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. 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