Long‐Term Outcomes of Catheter Ablation in Ventricular Tachycardia Electrical Storm: A Retrospective Cohort Study

ORAL PRESENTATION

POSTER PRESENTATIONS

Sex differences have the potential to impact diagnostic and therapeutic interventions in a wide variety of medical conditions, and cardiac arrhythmias are no exception.1 Studies evaluating pathophysiology, disease course, and therapeutic options for cardiac arrhythmias have been performed predominantly in male patients. However, catheter and device-based therapies coupled with landmark clinical trials have contributed to an improved understanding of this important aspect. The objective of this review is to present the current state of knowledge on sex differences in cardiac arrhythmias with a focus on clinical management, while highlighting gaps in knowledge that would benefit from future investigation. ### Atrial Fibrillation and Atrial Flutter #### Disease Burden Atrial fibrillation (AF) and atrial flutter (AFL) are the most commonly encountered tachyarrhythmias in clinical practice, with significant implications for public health and healthcare costs. Stroke, hospitalization, and loss of productivity are the major consequences of AF.2 The incidence of AF (per 1000 person-years) is reported to be between 1.6 and 2.7 in women and between 3.8 and 4.7 in men.2 The age-adjusted incidence and prevalence of AF is lower in women compared with that in men, and accordingly, the lifetime risk of AF from the Framingham Heart Study at 40 years of age was higher in men (26.0% for men versus 23.0% for women).3 Another analysis from the Framingham Heart Study demonstrated no significant sex differences in the risk of developing AFL.4 The prevalence of AF continues to rise among both men and women. In a study investigating the global burden of disease from 1980 to 2010, there was not only an increase in overall burden, incidence, and prevalence of AF, but most importantly an increase in AF-associated mortality in both men and women (Figure 1).5 The age-adjusted mortality for women was consistently higher compared with that for men from 1990 to 2010 (Figure …

Radio frequency ablation for VT – A cost-effective tool to combat SCD in developing countries

Long-Term Outcomes of Catheter Ablationof Electrical Storm in Nonischemic DilatedCardiomyopathy Compared WithIschemicCardiomyopathy.

HeartMate 3 (HM3) is a fully magnetically levitated continuous flow left ventricular assist device (LVAD). In patients with HM3 and recurrent ventricular tachycardia (VT), data on the outcomes of catheter ablation (CA) are insufficient. We report our institutional experience with CA of VT in patients with the HM3.Consecutive patients with HM3 and recurrent drug-refractory VT undergoing CA were included. Ablation sites were identified using activation/entrainment mapping (stable VTs) and/or late/fractionated potential ablation and pace-mapping (unstable VTs). Between 2016-2023 a total of 431 patients (age 58±13, INTERMACS 3±0.98, 44% ischemic cardiomyopathy) received an HM3 LVAD at our institution. Of these, 15 (3.4%) underwent CA for recurrent VT despite therapy with 1.3±0.8 antiarrhythmic drugs a median of 700 days from the LVAD surgery (2 patients <1 month from the surgery). The LV access was transseptal in 12 (80%) cases, retrograde aortic in 2 (13%) and both in 1 (7%). A total of 23 distinct VTs were targeted. Of these, 21 (91%) were mapped with activation/entrainment mapping, always utilizing an intracardiac RV reference due to excessive surface ECG noise, and 2 (9%) were hemodynamically unstable with reduced LVAD flows and targeted with substrate-based ablation. A total of 3 (13%) VTs were targeted adjacent to the HM3 inflow cannula, and 20 (87%) from substrate remote from the HM3 cannula. At post-procedural programmed ventricular stimulation, non-inducibility of all targeted VTs was achieved in 13 (87%) patients, 1 patient had residual inducible clinical VT, and in 1 patient no post-procedural programmed stimulation was performed. Periprocedural complications occurred in 1 (7%) case (small pericardial effusion not requiring intervention). At 12 months follow-up following the index procedure, no death occurred and one patient received heart transplantation. Of the remaining 14 patients, 6 (42%) remained free from VT (2 with VT ablation <1 month post-LVAD and 12 with VT ablation >=1 month post-LVAD). In this large single-center HM3 registry, a minority of patients underwent CA for recurrent drug-refractory VT (3.4% over a 7-year period). CA of VT in HM3 recipients is feasible and appears safe also when performed soon after LVAD surgery. Myocardial scar from the underlying cardiomyopathic process rather than the apical cannula is the dominant substrate responsible for VT in these patients.

AimsCatheter ablation (CA) of ventricular tachycardia (VT) in patients with structural heart disease is usually reserved for those with recurrent implantable cardioverter defibrillator (ICD) shocks or intolerant to anti-arrhythmic drugs. This meta-analysis synthesizes available trial evidence on CA for VT to clarify the role of this approach.Methods and resultsMEDLINE, PubMed, EMBASE and Cochrane were searched for randomized controlled trials (RCTs) of patients with structural heart disease allocated to receive either CA or standard treatment. Outcomes of interest were: all-cause and cardiovascular (CV) mortality, VT recurrence, incidence of appropriate ICD therapy, CV hospitalizations and VT storm. Evidence was appraised using the risk of bias tool and the grading of recommendations assessment, development and evaluation (GRADE) approach. Trial-level pairwise meta-analyses were conducted for all outcomes. Reconstructed time-to-event data meta-analysis was also performed for all-cause mortality 13 RCTs (n = 1735 patients) were included in the meta-analysis with a follow-up duration of 6–52 months. No significant reduction in all-cause mortality was observed at trial level meta-analysis (risk ratio [RR] 0.87, 95% confidence interval [CI] 0.70–1.08, heterogeneity [I2] = 0%), or reconstructed individual patient data meta-analysis [hazard ratio (HR) 0.79, 95%CI 0.57–1.11 at 3 years]. However, our pooled estimates, observed effect size and GRADE assessments suggest a potential mortality reduction in the ablation group. Patients who underwent CA experienced a significant reduction in CV hospitalizations (RR 0.78, 95%CI 0.65–0.94, I2 = 41%), VT storm (RR 0.78, 95%CI 0.63–0.97; I2 = 5%), VT recurrence (RR 0.83, 95%CI 0.72–0.95, I2 = 21%), and appropriate ICD therapy (RR 0.74, 95%CI 0.61–0.89, I2 = 32.5%) compared to control groups.ConclusionA potential all-cause mortality reduction by catheter ablation requires further confirmation in a properly powered RCT. No reduction in cardiovascular mortality was found. VT recurrence, CV hospitalizations, VT storm and ICD therapy were all significantly reduced by catheter ablation in patients with structural heart disease.Lay summaryWe examined the effectiveness of catheter ablation (CA) for treating ventricular tachycardia (VT) in patients with structural heart disease, particularly those facing recurrent implantable cardioverter defibrillator shocks or unable to tolerate medications by analysing several randomized controlled trials. The findings suggest that while CA may not significantly reduce overall mortality, it can lead to fewer recurrences of VT and hospitalizations related to cardiovascular problems.

The “modern” era of the treatment of ventricular tachyarrhythmias with device-based therapy may have begun in 1899, when Prevost and Battelli noted, almost as an afterthought, that direct current shock could terminate ventricular fibrillation (VF) in dogs.1 Three decades later, pioneering work in the field of defibrillation concluded that the passage of electrical current across the heart can both initiate and terminate VF.2,3 Still, little attention was paid to this phenomenon, as evidenced by Paul Dudley White’s Heart Disease , which devoted less than half a page to VF and characterized the arrhythmia as “a condition of little importance so far as we know now.”4 In 1947, the thoracic surgeon Claude Beck saved the first human life by the successful use of cardiac defibrillation in a 14-year-old boy who developed VF during a thoracic surgical procedure and went on to achieve a full recovery.5 These early accomplishments provided the foundation for the landmark work of Mirowski and Mower that ultimately led to the development of the implantable cardioverter-defibrillator (ICD) and its introduction in humans in 1980.6 Pacing may prevent sudden cardiac death due to bradyarrhythmias and in certain circumstances such as torsade de pointes associated with congenital long-QT syndrome (LQTS) and pause-dependent ventricular tachycardia (VT). Although no controlled studies exist, retrospective analyses suggest that recurrent torsade de pointes in patients with LQTS may be prevented by continuous pacing.7 Early clinical data on small numbers of patients suggested that the combination of β-adrenergic blockade plus continuous pacing reduced the number of syncopal events and the anticipated rate of sudden death in high-risk LQTS patients.8 The beneficial effects of pacing may be limited to patients with LQT2 and LQT3, in which the transmural dispersion of repolarization worsens steeply during bradycardia.9 Genotype-phenotype correlation confirms that …

Background Ablation of ventricular tachycardia (VT) is an effective and safe treatment option in symptomatic patients under antiarrhythmic drugs or patients with frequent ICD therapies. Purpose We aimed to evaluate outcomes of VT catheter ablation in patients with ischemic VT. Methods All of the patients who underwent VT catheter ablation between June 2014 and November 2018 were included. Results 128 patients (120 male, 8 female) were included and mean age was 65 ± 10 years. Mean ejection fraction was 28.6 ± 8.2 %. Baseline characteristics were listed in Table-1. Mean follow-up was 22.3 ± 6.4 months. 52 (46.6 %) patients were admitted with electrical storm. Acute success rate was 96.6%. Complications including transient ischemic attack, deep venous thrombosis, pericardial effusion and inguinal hematoma were developed in 6 patients. Recurrence of VT was occured in 44 (34.4 %) patients and the presence of PCI history and admission with electrical storm were predictors of recurrence. All cause mortality was occured in 39 patients and predictors of all cause mortality was detected as follows; diabetes, NYHA stage >2, lower levels of EF and higher BNP levels. Cardiovascular mortality was developed in 28 patients and predictors were defined as, lower levels of EF, higher BNP levels and number of shock after index ablation. VT recurrence was not found to be related with both cardiovascular and all cause mortality. Conclusion VT ablation is a safe and effective option in patients with ischemic VT who are symptomatic despite optimal medical treatment. Admission with electrical storm and history of PCI were predictors of VT recurrence after ablation. Higher levels of BNP, lower EF values are related with both all cause and cardiovascular mortality. Table-1 Gender, male, (%) 120(93,8) Age(year) 65,5 ± 9,7 HT 93(72,7) DM 35(27,3) AF 41(32,0) NYHA class(pre-ablation) IIIIII IV 71(55,5)27(21,1)25(19,5) 5(3,9) Previous PCI 83(64,8) Previous Cardiac surgery CABG AVR MVR 72(56,3) 70(54,7 1(0,8) 4(3,1) LV EF (%)≤3031-40 ≥41 28,6 ± 8,290(70,3)28(21,9) 10(7,8) Electrical storm 52(40,6) LV EDD (mm) 63,8 ± 8,5 Baseline characteristics

Options for ventricular tachycardia ablation after double valve replacement

Background Catheter ablation (CA) is an established therapy for drug-resistant ventricular tachycardia (VT). Although previous reports suggest higher recurrence and mortality rates in patients presenting with electrical storm (ES), data on mid- and long-term outcomes remain scarce. We aimed to evaluate the clinical characteristics and long-term outcomes of patients presenting with ES undergoing VT ablation. Methods Single-centre registry of consecutive patients undergoing scar-related VT ablation from 2010 to 2024. ES was defined as ≥3 episodes of sustained VT or ventricular fibrillation in 24h. Clinical and procedural characteristics were assessed and compared between groups. The outcomes of interest were VT-free survival and all-cause mortality. Safety outcome was a composite of tamponade, hemodynamic decompensation, acute heart failure, stroke, and procedure-related mortality. Results A total of 298 patients (aged 65±13years, 91% male, mean left ventricular ejection fraction [LVEF] 34±11%, 67% with ischemic cardiomyopathy, 20% redo procedures) were included. Among those, 32% (n=96) had ES at presentation. Compared to those without ES, patients with ES had worse functional status (NYHA III-IV: 38.5% vs. 17.8%, P<0.001), although there were no differences regarding age, sex, aetiology, and LVEF. Procedure and fluoroscopy duration were similar (165 vs. 154 min, P=0.20; and 15 vs. 13 min, P=0.20; respectively), and acute non-inducibility of VT was achieved in 81.4% (P=0.772). Major complications rate was higher in the ES group (5.2% vs. 1.0%, P=0.025). During a median follow-up of 3.4 (IQR 1.4-7.2) years, 127 patients (42.6%) suffered a VT relapse and 104 (34.9%) died. Compared to non-ES group, patients presenting with ES had higher rates of VT recurrence (53.3%/year vs. 23.6%/ year, log rank P=0.014) and death (16.4%/ year vs. 9.7%/ year, log rank P=0.007). – Figure 1. ES remained independently associated with VT recurrence, even after adjusting for six clinical confounders (aHR 1.50 [95% CI 1.02-2.19], P=0.039). Non-ischaemic aetiology (aHR 1.79 [95% CI 1.21-2.66], P=0.004), atrial fibrillation (aHR 1.71 [95% CI 1.17-2.52], P=0.006) and chronic kidney disease (aHR 1.59 [95% CI 1.08-2.35], P=0.019) were the other predictors of relapse. Conclusions Patients presenting with ES undergoing VT ablation had higher rates of VT recurrence, mortality, and major complications compared to those without ES, even achieving similar acute procedural success. ES was an independent predictor of poorer long-term outcomes, highlighting the need for targeted strategies to improve prognosis in this high-risk population

Funding Acknowledgements Type of funding sources: None. Background Catheter ablation is an increasingly used treatment option for patients with recurrent ventricular tachycardia (VT) or electrical storm (ES). The QDOT Micro (QDOT) Catheter (Biosense Webster) is a novel radiofrequency ablation catheter that was found to allow rapid and effective pulmonary vein isolation among patients with atrial fibrillation. There is no published data on the safety and efficacy of catheter ablation for VT using the QDOT catheter, and few data allow a direct comparison of different technologies in this setting. Purpose to assess outcomes of CA for VT among patients with structural heart disease using the QDOT catheter, and compare them to those observed with the Thermocool Smarttouch (TC-ST, Biosense Webster) catheter. Methods we conducted a dual-center, observational, prospective study enrolling patients with structural heart disease and recurrent VT/ES undergoing catheter ablation with the QDOT catheter. For comparison, we performed a 1:1 propensity score matching to identify patients who underwent VT CA with the TC-ST catheter, using the nearest neighbor method. Propensity score was based on gender, age, etiology of structural heart disease, left ventricular ejection fraction, electrical storm, and number of previous CAs for VT. The primary efficacy outcome was freedom from recurrent VT, as assessed by implantable defibrillator (ICD) interrogation; the primary safety outcome was in-hospital complications. Results Forty propensity-matched patients were included in the analysis (QDOT, n=20; TC-ST, n=20); baseline clinical characteristics are resumed in Table. After a median follow-up of 7 months, survival free from any recurrent VT measured 74 (95% CI, 57-97)% and 69 (95% CI, 51-93)% in the QDOT and TC-ST groups, respectively (log-rank p=0.54, Figure A), while survival free from ICD shocks was 95 (95% CI, 86-100)% versus 84 (95% CI, 69-100)% (log-rank p=0.26, Figure B). There were no major complications in the QDOT group, while three patients (15%) in the TC-ST had a primary safety event (p=0.23; femoral pseudoaneurysm, n=1; cardiac tamponade, n=1; aortic cusp perforation, n=1). Conclusion In a cohort of patients with structural heart disease and recurrent VT or ES, the novel QDOT ablation catheter had similar efficacy and safety compared to the TC-ST catheter. Interestingly, no major procedural complications were observed with the QDOT catheter, suggesting that this device may be safe even in most challenging patients.

Acute and long term outcomes of catheter ablation using remote magnetic navigation for the treatment of electrical storm in patients with severe ischemic heart failure

Background It has been suggested that antiarrhythmic drugs (AAD) are less effective and safe in slow ventricular tachycardia (VT) due to their effect on conduction velocity, which could stabilize reentry. Conversely, catheter ablation aims to disrupt the VT circuit. Because of the distinct mechanisms of action of AAD and catheter ablation on the VT circuit, VT cycle length (VT-CL) may play a crucial role in determining their therapeutic efficacy. Therefore, VT-CL could be important in selecting VT treatment. Purpose The aim of this study was to assess the impact of VT-CL on outcomes following catheter ablation or antiarrhythmic drugs in AAD-naïve patients with ischemic cardiomyopathy presenting with VT. Methods This is a post hoc analysis of the previously published Substrate Ablation vs Antiarrhythmic Drug Therapy for Symptomatic Ventricular Tachycardia (SURVIVE-VT) trial. In summary, 144 patients with ischemic cardiomyopathy and symptomatic VT were randomized to receive either catheter ablation (N=71) or AAD (N=73) as first-line therapy. We analyzed VT recurrence, implantable cardioverter-defibrillator (ICD) therapies, and the incidence of slow/incessant VT/VT storm using Cox proportional hazard models, with treatment and VT-CL interaction terms, adjusted for age. Missing VT-CL data for five patients were imputed using the median value. Results In patients with chronic ischemic heart disease and VT treated with either AAD or catheter ablation, a significant interaction was observed between clinical VT-CL and treatment effect on VT recurrence (p=0.016 for the interaction). Specifically, slower VT cycle lengths were associated with higher rates of VT recurrence (hazard ratio per 10 ms [HR] 1.094, 95% confidence interval [CI] 1.015, 1.179; p=0.037) in patients treated with AAD, while no significant effect was observed in those undergoing catheter ablation (see Figure 1). Survival freedom from VT recurrence in patients with VT-CL ≥300ms was significantly higher in patients treated with catheter ablation (78.8% vs 58.1%, log-rank p=0.044, see Figure 2). As expected, VT-CL was significantly associated with a higher risk of slow/incessant VT/VT storm (HR per 10 ms 1.115, 95% CI 1.017-1.222, p=0.047) but was not associated with ICD therapies (HR per 10 ms 1.082, 95% CI 0.994-1.178, p=0.102). Conclusion VT-CL significantly influences treatment outcomes, with slower VT cycles associated with an increased risk of VT recurrence in patients treated with AAD, but not in those undergoing catheter ablation. Therefore, VT-CL should be taken into consideration when selecting the optimal therapy for patients with ischemic cardiomyopathy and VT.Figure 1Figure 2

When to sear, when to burn, and when to chop: The art of substrate modification