Pan-Asia United States Prevention of Sudden Cardiac Death - PAUSE-SCD

Contribution To Literature:

The PAUSE-SCD trial showed that, among patients with monomorphic VT and cardiomyopathy of varied causes, VT ablation performed early at time of ICD implantation reduced the composite outcome of VT recurrence, CV hospitalization, or death, versus conventional therapy with ICD implantation alone.


The goal of the trial was to compare the efficacy of early catheter ablation of monomorphic ventricular tachycardia (VT) versus conventional medical therapy at time of implantable cardioverter-defibrillator (ICD) implantation among patients with a cardiomyopathy of varied causes.

Study Design

The PAUSE-SCD trial was a prospective, international, multicenter randomized controlled trial (RCT) at 11 academic centers across Asia. Participants were randomized in a 1:1 fashion to catheter ablation within 90 days of ICD implantation (n = 67) versus conventional therapy (beta-blockers, antiarrhythmics at discretion of primary physician, n = 66). Patients who declined ICD (n = 47) were followed in a parallel registry after stand-alone ablation therapy followed by medical therapy.

  • Total enrolled participants: 180
  • Total randomized participants: 133
  • Median duration of follow-up: 31.3 months
  • Mean patient age: 55 years
  • Percentage female: 19%

Inclusion criteria:

  • Age >18 years
  • Structural heart disease
  • Indication for a secondary prevention ICD for monomorphic VT or primary prevention ICD with inducible monomorphic VT during electrophysiology study

Exclusion criteria:

  • Acute ST-segment elevation myocardial infarction within 60 days
  • Revascularization within 45 days
  • Reversible causes of VT or cardiomyopathy
  • Left ventricular ejection fraction (LVEF) <15%
  • New York Heart Association class IV status
  • Life expectancy <1 year

Other salient features/characteristics:

  • LVEF: mean 40%
  • 34.7% ischemic cardiomyopathy, 30.6% nonischemic cardiomyopathy, 34.7% arrhythmogenic right ventricular cardiomyopathy
  • Ablation performed median of 2 days before ICD implantation
  • Clinical presentation: hemodynamically tolerated VT in 47%, cardiac arrest in 5.0%

Principal Findings:

The primary outcome, a composite of VT recurrence, cardiovascular (CV) hospitalization, or death, for early VT ablation vs. conventional therapy, was: 49.3% vs. 65.5% (p = 0.04).

Secondary outcomes for early VT ablation vs. conventional therapy:

  • VT recurrence: 34.9% vs. 58.2% (p = 0.02)
  • ICD shocks: 10.0% vs. 24.6% (p = 0.03)
  • Antitachycardia pacing: 16.2% vs. 32.8% (p = 0.04)
  • CV hospitalization: 32.0% vs. 33.7% (p = 0.55)
  • Death: 8.9% vs. 8.8% (p = 0.62)

There was an 8.3% procedural-related complication rate.


The results of this trial show that, among patients with monomorphic VT and cardiomyopathy of varied cause, early catheter ablation of VT at time of ICD implantation reduced the composite of VT recurrence, CV hospitalization, or death. This reduction was driven by reduction in VT recurrence without differences in CV hospitalization or death. Importantly, this study included patients with both ischemic and nonischemic cardiomyopathy and is the first RCT of VT ablation in Asia, both of which improved the generalizability of the study. Procedural risks were 8% in the trial, with two life-threatening cardiac perforations leading to one fatality.

Overall, the study provides additional evidence to the benefits of early VT ablation at time of ICD implantation; however, larger studies are needed to better determine the risks versus benefits of first-line ablation and impact on patient mortality.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Prevention, Implantable Devices, EP Basic Science, Genetic Arrhythmic Conditions, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Adrenergic beta-Antagonists, Anti-Arrhythmia Agents, Arrhythmias, Cardiac, Arrhythmogenic Right Ventricular Dysplasia, Cardiomyopathies, Catheter Ablation, Death, Sudden, Cardiac, Defibrillators, Implantable, Electrophysiology, Heart Arrest, Pacemaker, Artificial, Secondary Prevention, Shock, Tachycardia, Ventricular

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