Risk Factors for Early Mortality After VT Ablation

Abstract

R adiofrequency catheter ablation (RCA) has become a standard component of management strategies for recurrent ventricular tachycardia (VT) that results from ventricular scar.Current consensus favors catheter ablation to reduce symptoms due to VT recurrence and implantable cardioverter-defibrillator (ICD) shocks, although a mortality benefit of catheter ablation has not been proven. In the recent VANISH (Ventricular Tachy-cardia Ablation versus Escalated Antiarrhythmic Drug Therapy in Ischemic Heart Disease) trial, RCA in patients with ischemic cardiomyopathy and VT despite amiodarone therapy reduced the combined endpoint of death, VT storm, and ICD shocks compared with further escalation of antiarrhythmic drug therapy (1). This result was driven by reductions in VT storm and ICD shocks, rather than a mortality benefit. Two other randomized trials of VT ablation in patients with ischemic cardiomyopathy also reported reductions in VT recurrence (but no mortality benefit) with RCA versus a control arm without antiarrhythmic drug escalation (2,3). Importantly, none of these trials was sufficiently powered to detect mortality differences.In this issue of the Journal, Santangeli et al. (4) present the early (31-day) mortality data from a multicenter registry of VT ablation in the context of structural heart disease. In this large registry, 2,061 patients underwent RCA for VT, of whom 47% had nonischemic cardiomyopathy, 33% had severe heart failure symptoms, and 35% presented with VT storm.Fifty-six percent of the patients had unmappable arrhythmias, and in only 67% was VT demonstrated to be noninducible after ablation. These data, therefore, represent a typical population undergoing VT ablation. The association between VT recurrence and 1-year mortality in the same cohort has been published previously; the overall combined transplant/ mortality rate was 15% at 1 year but 29% in those with recurrent VT (5). In the present study, the authors focused on early mortality, which reflects patient baseline characteristics, as well as acute hospital care.Overall, 5% of patients died within 31 days of RCA after major procedural complications in only 0.6%.Not surprisingly, the sickest patients (those with poor ventricular function, renal impairment, and VT storm) had a higher risk of early mortality. Procedural factors such as inducibility of unmappable VT and recurrence after RCA were also associated with increased mortality. Although VT recurrence was associated with a higher risk of death, only 22% of deaths were known to be arrhythmic, and one-half were known not to be. Even in those who died after recurrence of VT, death was known to be VT related in only 40%. These results are in keeping with randomized trials and make progress in explaining the difficulty in demonstrating a mortality benefit from VT ablation. Death due to worsening heart failure is common in this population, and predictors of death in this group are also predictors of death in advanced heart failure (6). VT in this setting may be