Time to pause ventricular tachycardia: the PAUSE-SCD trial

Excerpt

Patients with structural heart disease (SHD) are at increased risk for ventricular arrhythmias (VA) and mortality. Albeit, implantable cardiac defibrillators (ICD) have been efficacious in improving survival, while recurrent ventricular tachycardia (VT) with subsequent ICD shocks reduce quality of life and is associated with increased mortality [1]. Antiarrhythmic drugs (AADs) have been of limited value given suboptimal efficacy and numerous side effects [1]. Conversely, catheter ablation (CA) has evolved as a useful tool to control VA and improve quality of life. Most VT randomized controlled trials (RCTs) comparing CA with medical therapy have been conducted in patients with ischemic cardiomyopathy (ICM), and although not powered to show an all-cause mortality benefit, they have reported substantial superiority of CA to standard medical therapy in reducing ICD interventions and VT recurrences [2, 3]. In fact, the VANISH trial showed that CA reduced the composite primary outcome of death, VT storm, or appropriate ICD shock compared to patients receiving an escalation in AADs [4]. On the other hand, the role of CA of VT in patients with non ischemic cardiomyopathy (NICM) is variable and largely depends on the arrhythmogenic substrate. Furthermore, outcome data on mortality benefit of CA for VT in NICM are limited [5, 6]. Patients with NICM, which are highly prevalent in Asia, have not been previously enrolled in RCTs of VT ablation. Few observational studies have reported encouraging outcomes in this population. Tung et al. [7] reported, in a large international VT ablation study of 2000 patients, that CA of VT in patients with structural heart disease results in 70% freedom from VT recurrence similar for both ICM and NICM (72% in ICM and 68% in NICM), with an overall transplant and/or mortality rate of 15% at 1 year (same for ICM and NICM). Subsequently, our group analyzed a large-scale data of NICM patients from the 2003–2014 National Inpatient Sample databases [8]. A propensity score matched analysis was used to compare patients undergoing CA versus medical therapy of VT related to NICM and described the temporal trends in utilization and in-hospital outcomes of CA of VT in patients with NICM in the USA. Out of 133,529 patients hospitalized with the principal diagnosis of VT in NICM, 14,651 (11.0%) underwent CA. After propensity score matching, in-hospital mortality occurred in 172 of 14,318 (1.2%) patients in the CA group, compared with 297 of 14,156 (2.1%) of patients undergoing medical therapy (adjusted OR, 0.53; 95% CI, 0.43–0.66), which translates into a 47% relative reduction in all-cause mortality. …