Long-Term Clinical Outcomes From Catheter Ablation of SVT

Abstract

Source: Fremed MA, Silver ES, Joong A, et al. Long-term patient experience following acutely successful ablation of supraventricular tachycardia substrate in children. Pediatr Cardiol. 2021;42(1):109-115; doi:10.1007/s00246-020-02459-zInvestigators from Columbia University Medical Center, New York, NY, and Northwestern University Feinberg School of Medicine, Chicago, IL, conducted a cross-sectional survey of pediatric patients who underwent a successful ablation for supraventricular tachycardia (SVT) to assess patient-reported long-term symptoms. Patients who underwent a successful ablation for SVT at the study institution from 2008–2012 were eligible. Participants or their caregivers were administered a survey via email, telephone, or in person that queried their post-ablation events such as recurrence, need for a repeat ablation, and post-ablation symptoms. Demographics, electrophysiologic diagnosis, and modality of the initial ablation were obtained from the participants’ medical record.The primary outcome was patient-reported cure, defined as an affirmative response to the question “Do you consider yourself/your child cured?” Investigators used descriptive statistics to assess patient-reported cure. Variables associated with patient-reported cure also were assessed.There were 269 successful ablations for SVT during the study period in a total of 259 patients, 147 of whom completed the survey. Respondents were mostly male (55%), had an accessory pathway present as the reason for SVT (76%), and received radiofrequency ablation (75%). The mean age of respondents at the time of the initial ablation was 15.2 years, with the mean follow-up time since ablation being 7.2 years.Most (84%) reported themselves cured. Recurrence occurred in 16% of respondents, and 10% required repeat ablation. Patient-reported cure was not associated with electrophysiologic diagnosis or ablation modality, though significantly more had recurrence of SVT after initial success achieved with cryoablation compared to radiofrequency ablation. Significantly more patients who did not feel cured (vs those who did feel cured) reported post-ablation symptoms (87% vs 27%, respectively; P <0.01) and experienced recurrence of arrhythmia (42% vs 10%, respectively; P = 0.01).Investigators conclude that most patients consider themselves cured after an initially successful ablation despite some continuing to report post-ablation symptoms or recurrence of arrhythmia.Dr Spar has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.SVT is the most common rhythm disturbance in children, occurring in 0.1% to 0.4% of children.1 SVT not only has clinical impact from tachycardia episodes but has been demonstrated to affect quality of life.2 The most common forms of SVT include AV reentrant (AVRT) and AV nodal reentrant tachycardia (AVNRT), with AVRT being more common in patients who undergo catheter ablation. AVRT requires an accessory pathway (AP), which is located on the AV valve annulus, to participate in tachycardia. APs that have anterograde conduction demonstrate ventricular pre-excitation on ECG. AVNRT is the result of dual AV nodal pathways, described as fast and slow AV nodal pathways, that participate in tachycardia. For older children with weights greater than 15kg, catheter ablation is curative therapy and allows patients to avoid antiarrhythmic therapy. In patients with anterograde AP conduction, ablation eliminates risk for sudden death secondary to rapidly conducting atrial fibrillation.3 Typical indications for catheter ablation of SVT include: SVT with ventricular dysfunction, when medical therapy is not effective or not tolerated, family wishes to avoid chronic antiarrhythmic medication, and SVT with hemodynamic compromise.3 Acute success rates of catheter ablation range from 87% to 98%,3,4 with early recurrence ranging from 5% to 20% depending on substrate location and energy used. Risk of serious complication is less than 1%.3 There has been limited investigation of long-term results (years after ablation), with recurrence rates reported to be about 10%.5,6The investigators in the current study reviewed patients who underwent catheter ablation of SVT at a single institution. Of the 280 ablation procedures, 96% were acutely successful. Of these patients, 59% were reached for a median follow-up of 7.2 years. The majority of patients had an ablation for an AP. Subjective cure was reported in 124 of 147 of the study participants. A large percentage of those who reported no cure had documented recurrence. Of interest, 10% of patients who felt cured had recurrence of tachycardia. Patients who did not feel cured were more likely to report symptoms and have experienced arrhythmia. Documented recurrence of tachycardia substrate occurred in 16% of the population, with 73% within the first year and of those 52% within the first 2 months post-procedure.Long-term subjective recurrence after catheter ablation of SVT is relatively low. Recurrence is more likely in patients with persistent symptoms and in those who have had cryoablation rather than radiofrequency ablation.