Ablation superior to drugs in recurrent ventricular tachycardia

Nearly 100, 000 implantable cardiac defibrillators (ICDs) are implanted every year in N. America to treat patients at risk of ventricular tachycardia (VT)  following myocardial infarction.  ICD activation for VT is relatively common and associated with recurrent hospitalizations, reductions in quality of life and mortality. It is therefore important to understand the best course of action to suppress recurrent VT, either through intensifying antiarrhythmic therapy or catheter ablation.  In this multicenter trial of patients with ischemic cardiomyopathy and an ICD, subjects who presented with VT despite anti-arrhythmic therapy were randomized 1:1 in an open-label fashion to either catheter ablation or an escalated antiarrhythmic drug regimen. In the medical therapy arm, amiodarone was initiated or the dose was escalated as appropriate; mexiletine was added if they were already on at least 300 mg per day of amiodarone. The primary outcome was a composite of death, three or more documented episodes of ventricular tachycardia within 24 hours (ventricular tachycardia storm), or appropriate ICD shock based on an intention-to-treat strategy.  In total, 259 patients were enrolled with a median follow-up of 27.9±17.1 months.  Catheter ablation significantly reduced the primary end-point from 68.5% to 59.1% (HR 0.72; 95% CI, 0.53 to 0.98; P=0.04) primarily driven by a reduction in recurrent VT with no discernable effect on mortality.

Conclusions

In this well conducted but small scale randomized controlled trial, catheter ablation proved superior to escalation of antiarrhythmic drug therapy in ischemic scar-related VT though neither therapy effectively treated the plurality of patients.  Scar-mediated recurrent VT refractory to baseline medical therapy maybe improved with ablation without an obvious signal for harm though larger scale studies are warranted.

Sapp JL, Wells GA, Parkash R, Stevenson WG, Blier L, Sarrazin JF, Thibault B, Rivard L, Gula L, Leong-Sit P, Essebag V, Nery PB, Tung SK, Raymond JM, Sterns LD, Veenhuyzen GD, Healey JS, Redfearn D, Roux JF, Tang AS. Ventricular Tachycardia Ablation versus Escalation of Antiarrhythmic Drugs. N Engl J Med. 2016 Jul 14;375(2):111-21.

Authors: Hussain Contractor & James M. McCabe