Venturing Into Ventricular Arrhythmia Storm
Ablation has substantial evidence base in the management of ventricular arrhythmia (VA). It can be a 'lifesaving' procedure in the acute setting of VA storm. Current reports on ablation in VA storm are in the form of small series and have relative small representation in a large observational series. The purpose of this study was to systematically synthesize the available literature to appreciate the efficacy and safety of ablation in the setting of VA storm. The medical electronic databases through 31 January 2012 were searched. Ventricular arrhythmia storm was defined as recurrent (≥3 episodes or defibrillator therapies in 24 h) or incessant (continuous >12 h) VA. Studies reporting data on VA storm patients at the individual or study level were included. A total of 471 VA storm patients from 39 publications were collated for the analysis. All VAs were successfully ablated in 72% [95% confidence interval (CI) 71–89%] and 9% (95% CI: 3–10%) had a failed procedure. Procedure-related mortality occurred in three patients (0.6%). Only 6% patients had a recurrence of VA storm. The recurrence of VA was significantly higher after ablation for arrhythmic storm of monomorphic ventricular tachycardia (VT) relative to ventricular fibrillation or polymorphic VT with underlying cardiomyopathy (odds ratio 3.76; 95% CI: 1.65–8.57; P = 0.002). During the follow-up (61 ± 37 weeks), 17% of patients died (heart failure 62%, arrhythmias 23%, and non-cardiac 15%) with 55% deaths occurring within 12 weeks of intervention. The odds of death were four times higher after a failed procedure compared with those with a successful procedure (95% CI: 2.04–8.01, P < 0.001). Ventricular arrhythmia storm ablation has high-acute success rates, with a low rate of recurrent storms. Heart failure is the dominant cause of death in the long term. Failure of the acute procedure carries a high mortality.
Ventricular arrhythmia (VA) storm is increasingly being recognized as a distinctive arrhythmia syndrome with its specific management issues and prognostic consequences that differ from ventricular tachycardia (VT) and ventricular fibrillation (VF) episodes unrelated to storm. Implantable cardioverter defibrillator (ICD) is recommended as primary or secondary prevention of sudden death in patients with cardiomyopathy and life-threatening genetic cardiac disorders. However, despite the presence of an ICD, the appearance of a VA storm still portends a high mortality. The AVID study which followed secondary prevention ICD recipients observed a 5.6-fold relative increase in mortality in the first 12 weeks following the development of VA storm and 2.4-fold over 3 years when compared with those who had VA episodes unrelated to storm. Indeed every defibrillator shock therapy multiplies the mortality risk and the impact of multiple therapies over a short period can have unpredictable consequences.
Radiofrequency catheter ablation (RFA) is evolving as the standard care in patients with VA storm, with VT-free long-term survival improved with early invasive intervention. Other approaches, such as transcoronary ethanol ablation, generally, remain as a treatment of last resort after a failure of RFA. Most of the published data on VA storm ablation are single-centre small series or case reports and have relative small representation within large multi-centre VT ablation series. Therefore, given the lack of large data, interpretability of reported information on survival outcomes in VA storm management remains contentious. Despite this relatively modest supporting evidence, current guidelines endorse the role of catheter ablation for VA storm management with a consensus on early intervention. We, therefore, undertook this systematic review to organize the published data on high-risk VA storm patients and examine the efficacy and safety of VA storm ablation.
Abstract and Introduction
Abstract
Ablation has substantial evidence base in the management of ventricular arrhythmia (VA). It can be a 'lifesaving' procedure in the acute setting of VA storm. Current reports on ablation in VA storm are in the form of small series and have relative small representation in a large observational series. The purpose of this study was to systematically synthesize the available literature to appreciate the efficacy and safety of ablation in the setting of VA storm. The medical electronic databases through 31 January 2012 were searched. Ventricular arrhythmia storm was defined as recurrent (≥3 episodes or defibrillator therapies in 24 h) or incessant (continuous >12 h) VA. Studies reporting data on VA storm patients at the individual or study level were included. A total of 471 VA storm patients from 39 publications were collated for the analysis. All VAs were successfully ablated in 72% [95% confidence interval (CI) 71–89%] and 9% (95% CI: 3–10%) had a failed procedure. Procedure-related mortality occurred in three patients (0.6%). Only 6% patients had a recurrence of VA storm. The recurrence of VA was significantly higher after ablation for arrhythmic storm of monomorphic ventricular tachycardia (VT) relative to ventricular fibrillation or polymorphic VT with underlying cardiomyopathy (odds ratio 3.76; 95% CI: 1.65–8.57; P = 0.002). During the follow-up (61 ± 37 weeks), 17% of patients died (heart failure 62%, arrhythmias 23%, and non-cardiac 15%) with 55% deaths occurring within 12 weeks of intervention. The odds of death were four times higher after a failed procedure compared with those with a successful procedure (95% CI: 2.04–8.01, P < 0.001). Ventricular arrhythmia storm ablation has high-acute success rates, with a low rate of recurrent storms. Heart failure is the dominant cause of death in the long term. Failure of the acute procedure carries a high mortality.
Introduction
Ventricular arrhythmia (VA) storm is increasingly being recognized as a distinctive arrhythmia syndrome with its specific management issues and prognostic consequences that differ from ventricular tachycardia (VT) and ventricular fibrillation (VF) episodes unrelated to storm. Implantable cardioverter defibrillator (ICD) is recommended as primary or secondary prevention of sudden death in patients with cardiomyopathy and life-threatening genetic cardiac disorders. However, despite the presence of an ICD, the appearance of a VA storm still portends a high mortality. The AVID study which followed secondary prevention ICD recipients observed a 5.6-fold relative increase in mortality in the first 12 weeks following the development of VA storm and 2.4-fold over 3 years when compared with those who had VA episodes unrelated to storm. Indeed every defibrillator shock therapy multiplies the mortality risk and the impact of multiple therapies over a short period can have unpredictable consequences.
Radiofrequency catheter ablation (RFA) is evolving as the standard care in patients with VA storm, with VT-free long-term survival improved with early invasive intervention. Other approaches, such as transcoronary ethanol ablation, generally, remain as a treatment of last resort after a failure of RFA. Most of the published data on VA storm ablation are single-centre small series or case reports and have relative small representation within large multi-centre VT ablation series. Therefore, given the lack of large data, interpretability of reported information on survival outcomes in VA storm management remains contentious. Despite this relatively modest supporting evidence, current guidelines endorse the role of catheter ablation for VA storm management with a consensus on early intervention. We, therefore, undertook this systematic review to organize the published data on high-risk VA storm patients and examine the efficacy and safety of VA storm ablation.
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