Predictors of VT recurrence in patients with VT inducibility at the end of radiofrequency ablation: Should we use VT non-inducibility as a routine endpoint?

Introduction: It has been reported that ventricular tachycardia (VT) non-inducibility at the end of ablation is associated with less likely VT recurrence. However, it is not clear whether we should use VT non-inducibility as routine end point in VT ablation. The aim of this study was to evaluate VT recurrence in patients in whom VT non-inducibility could not be achieved at the end of the RF ablation and the factors attributing to the VT recurrence. METHODS and RESULTS: We analyzed 84 consecutive patients that underwent RF ablation, and 64 patients in whom VT non-inducibility could not be achieved were studied. The primary endpoint was recurrence of any sustained VT during the follow-up. During a median follow-up period of 1.4 years (IQR:0.3-2.0), 22 (34%) of the cases had VT recurrences. In the multivariate analysis showed that an LVEF≥35% (HR:0.21; 95% CI:0.07- 0.54; P<0.01) and successful identification and ablation of all clinical VT isthmuses (HR:0.21; 95% CI:0.03- 0.72; P=0.01) were independent predictors of fewer VT recurrences. RF ablation was associated with a 91.1% reduction in VT episodes. CONCLUSION: Even if VT non-inducibility could not be achieved, the patients with LVEF≥35% or in whom all clinical VT isthmuses could successfully be identify and ablated might be prevented from having VT recurrences. The validity of VT non-inducibility of any VT should be evaluated by each patient’s background and the results of the procedure.

Impact of chronic kidney disease on in-hospital mortality and clinical outcomes of catheter ablation of ventricular tachycardia: Insights from the national readmission database

Background: Catheter ablation is an effective treatment for ventricular tachycardia (VT), albeit the decision to undergo this procedure is often influenced by underlying comorbidities. The present study aims at evaluating the effects of chronic kidney disease (CKD) on clinical outcomes of VT ablation. Methods: We identified 7,212 patients who presented between 2016-2018 and underwent catheter ablation for VT. Their clinical data were retrospectively accrued from the national readmission database (NRD) using the corresponding diagnosis codes. We compared clinical outcomes between patients with chronic kidney disease (CKD-group) and patients without. Odds ratios (OR) for the primary and secondary outcomes were calculated, and multivariable regression analysis was utilized to adjust for confounding variables. Results: Compared with patients without CKD, patients in CKD-group were older (mean age 67.9 vs. 60.5 years, P <0.01), had a longer mean length of stay (8.73 vs. 5.69 days, P <0.01), and higher in-hospital mortality (OR 2.24, 95% confidence interval (CI) (1.29-3.88), P<0.01). CKD-group patients had increased risk of developing acute kidney injury (10% vs. 8.6%, P<0.01) and 30-day readmission rate due to VT (OR 1.77, 95% CI (1.17-2.69), P<0.01). Conclusion: In patients with CKD, VT ablation is associated with worse clinical outcomes in-hospital mortality and 30-day readmission rate. This significantly influences the decision-making prior to performing this procedure.

Catheter ablation supported by extracorporeal membrane oxygenation -last resort treatment of arrhythmic storm?

Introduction Arrhythmic storm (AS) is associated with high mortality, even with best medical care and hemodynamic support. If medical therapeutic failure, electrophysiological mapping and ablation are potential lifesaving therapies. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) provides temporary mechanical circulatory support and can be used as a salvage intervention in patients with cardiogenic shock. Considering the seriousness of AS and the technical complexity involved, catheter ablation supported by VA-ECMO is infrequently performed. We sought to assess the safety and effectiveness of emergent catheter ablation procedures performed in patients on VA-ECMO at our hospital. Methods Retrospective study of all ventricular tachycardia (VT) catheter ablation procedures performed with VA-ECMO support at a tertiary centre between 2016 and 2020. Follow-up data was obtained from review of electronical records. Results Five patients underwent 6 emergent VT ablation procedures due to AS. The median age was 62 years (range, 52) and 4 patients were men. Three patients had VT at admission, while 2 were admitted with an acute coronary syndrome and developed VT during the hospitalization. Four patients had ischemic heart disease, though only 1 had previous history of VT; the remaining patient presented no structural heart disease. Median left ventricle ejection fraction was 11% (range 30). All patients had incomplete response to amiodarone, lidocaine or overdrive pacing, before being proposed to catheter ablation. Four patients were on ECMO support before ablation, while 1 was cannulated during the procedure due to hemodynamic instability. Ablation was performed using a retrograde approach in 3 patients, and combined retrograde and transeptal access in 2; one patient had epicardial ablation after unsuccessful endovascular approach. Three patients had left ventricle substrate ablation and the remaining 2 of the right ventricle. No major complications were seen directly related to the procedures. The median length of stay in intensive care unit was 22 days (range 41 days). Weaning of VA-ECMO was accomplished in all patients. Two patient died during the same hospitalization (one due to uncontrolled arrhythmic events). At a median 23 months (range 31) of follow-up of the surviving patients, two had recurrence of VT but no one had return of AS. Conclusion In our sample VT ablation on VA-ECMO support was a safe procedure, with no immediate complications. However, as reported in the literature, a high mortality rate was observed both in-hospital and during follow-up, mostly related to advanced structural heart disease. Also, considerable VT recurrence rates were seen, but with no re-hospitalization. Our experience shows that catheter ablation is a life-saving procedure in otherwise uncontrollable AS and allowed absolute success in weaning VA-ECMO. FUNDunding Acknowledgement Type of funding sources: None.

Subcutaneous ICD combined with VT ablation for the secondary prevention of sudden cardiac death: pilot data from the prospective multinational SICD-VTAbl study

Background The aim of the Subcutaneous ICD Combined with Ventricular Tachycardia Ablation (SICD-VTAbl) Study is to provide preliminary data on the safety and efficacy of a management strategy that incorporates S-ICD implantation and VT ablation among patients with a secondary prevention indication for an ICD. We hypothesize that VT ablation for the prevention of monomorphic VT recurrence combined with S-ICD implantation for termination of life-threatening VT/VF is safe, while reducing the need for device interventions and systemic complications associated with conventional transvenous ICD implantation for secondary prevention. Methods SICD-VTAbl is an uncontrolled, prospective, multinational observational study, conducted in France, Germany, US (Rochester NY, and Rochester MN) and coordinated in Israel. We aim to prospectively enroll 30 patients presenting with scar-related VT/VF who will undergo VT ablation/substrate modification followed by S-ICD implantation. The primary endpoint is the first occurrence of S-ICD therapy (appropriate and inappropriate). Secondary endpoints include separate occurrence of appropriate and inappropriate ICD therapies, peri-procedural complications, and adverse clinical outcomes. Results We provide clinical, arrhythmia, and outcome data on the first 15 patients enrolled in the SICD-VTAbl Study through February 2021. Mean age was 59±12 years, 78% were males, 60% had New York Heart Association (NYHA) Class ≥II symptoms, 20% had renal insufficiency, and 33% were treated with an antiarrhythmic medication (all amiodarone). Periprocedural, arrhythmia, and long-term outcome data are provided in Table 1. There were no major complications associated with the VT ablation and the S-ICD implantation procedures. During a median follow-up of 6 months (interquartile range: 2–12 months), 2 patients (13%) received S-ICD therapy: one patient (7%) experienced VF terminated by the S-ICD and one patient experienced a single episode of inappropriate S-ICD therapy. Adverse events during follow-up, unrelated to study procedures, occurred in 3 patients (20%): hospitalization for heart failure exacerbation (N=1) and non-cardiovascular hospitalizations (N=2). None of the patients died during follow-up (Table 1). Conclusions Our preliminary data from the SICD-VTAbl Study suggest that a management approach that incorporates VT ablation followed by S-ICD implantation is safe and may lead to improved arrhythmia and clinical outcomes in patients presenting with a secondary prevention indication for an ICD. FUNDunding Acknowledgement Type of funding sources: Other. Main funding source(s): Research grant to Sheba Medical Center from Boston Scientific

Substrate Characterization and Outcomes of Ventricular Tachycardia Ablation in Titin Cardiomyopathy: A Multicenter Study

Background - Truncating variants of the titin gene (TTNtv) are a leading cause of dilated cardiomyopathy (DCM) and have been associated with an increased risk of ventricular arrhythmias. This study evaluated the substrate distribution and the acute and long-term outcomes of patients with TTN-related cardiomyopathy undergoing ventricular tachycardia (VT) ablation. Methods - This multicenter registry included 15 patients with DCM (age 59±11 years, 93% male, ejection fraction 30±12%) and genotypically confirmed TTNtvs who underwent VT ablation between July 2014 and July 2020. Results - All patients presented with sustained monomorphic VT, including electrical storm in 4 of them. A median of 2 VTs per patient were induced during the procedure (cycle-length 318±68 ms) and the predominant morphologies were left bundle branch block with inferior axis (39%) and right bundle branch block with inferior axis (29%). A complete map of the left ventricle (LV) was created in 12 patients and showed voltage abnormalities mainly at the periaortic (92%) and basal septal region (58%). A preprocedural cardiac magnetic resonance imaging was available in 13 patients and in 11 there was evidence of LV delayed gadolinium enhancement, with predominantly midmyocardial distribution. Sequential ablation from both sides of the septum was required in 47% of patients to target septal intramural substrate and epicardial ablation was performed in 20%. At the end of the procedure, the clinical VT was noninducible in all patients, while in 3 cases a non-clinical VT was still inducible. After a follow-up of 26.5±23.0 months, 53% of patients experienced VT recurrence, 20% received transplant or mechanical circulatory support and 7% died. Conclusion - The arrhythmogenic substrate in TTN-related cardiomyopathy involves the basal septal and perivalvular regions. Long-term outcomes of catheter ablation are modest, with high recurrence rate, likely related to an intramural location of VT circuits.