Patients who received catheter ablation had lower rates of death, ventricular tachycardia storm, or appropriate implantable cardioverter defibrillator (ICD) shock compared with patients who received antiarrhythmic drug therapy escalation, according to findings from the VANISH (Ventricular Tachycardia Ablation vs Escalated Antiarrhythmic Drug Therapy in Ischemic Heart Disease) trial published in the New England Journal of Medicine.
VANISH was a multicenter, randomized, controlled clinical trial that included patients who had ischemic cardiomyopathy and an ICD with ventricular tachycardia, despite the use of antiarrhythmic drugs.
Patients were randomly assigned to receive either catheter ablation with antiarrhythmic medication continuation or escalated drug therapy. Amiodarone was initiated in the escalated-therapy group if another agent had been used previously. If the dose had been less than 300 mg/d or mexiletine was added if the dose was already at least 300 mg/d, the amiodarone dose was increased.
The primary outcome was a composite of death, 3 or more documented episodes of ventricular tachycardia within 24 hours (ie, ventricular tachycardia storm), or appropriate ICD shock after a 30-day treatment period. This treatment period was implemented to exclude nonfatal outcomes that could occur before adequate drug loading was met or actual performance of catheter ablation.
Patients were included if they previously had a myocardial infarction, undergone placement of an ICD, and had experienced an episode of ventricular tachycardia during treatment with amiodarone or another class I or III antiarrhythmic drug within the previous 6 months.
There were 132 patients in the catheter ablation group and 127 patients in the escalated therapy group. The median follow-up was 27.9 ± 17.1 months. Of the patients in the ablation group, 59.1% experienced the primary outcome compared with 68.5% in the escalated therapy group (hazard ratio [HR] in the ablation group: 0.72; 95% confidence interval [CI]: 0.53-0.98; P=.04). The ablation group experienced a significantly lower rate of the primary outcome compared with the escalated therapy group.
However, the difference was not significant according to a post hoc sensitivity analysis that included events that occurred during the 30-day treatment period.
Thirty-six patients in the ablation group died compared to 35 patients in the escalated therapy group (HR: 0.96; 95% CI: 0.60-1.53; P=0.86). Ventricular tachycardia storm occurred in 32 patients in the ablation group vs 42 patients in the escalated therapy group (HR: 0.66; 95% CI: 0.42-1.05; P=.08). Finally, appropriate ICD shocks occurred in 50 patients in the ablation group vs 54 patients in the escalated therapy group (HR: 0.77; 95% CI: 0.53-1.14; P=.19).
In the escalated therapy group, 4 patients withdrew before the primary outcome occurred, along with 1 patient who underwent heart transplantation. In the ablation group, 3 did not undergo the procedure, 4 patients withdrew before the primary outcome occurred, 3 patients underwent cardiac transplantation, and 4 patients received escalated antiarrhythmic drug therapy.
“The benefit with respect to the primary outcome for ablation was driven by a reduction in the rates of ventricular tachycardia storm and ICD shocks,” researchers noted. “Sustained ventricular tachycardia at a rate below the detection limit of the ICD and adverse events that were attributed to treatment were more frequent among patients in the escalated therapy group.”
“This trial provides evidence that catheter ablation should be preferred over escalation of AAD [antiarrhythmic drug therapy] for the reduction of recurrent ventricular tachycardia in this population,” they concluded.
Sapp JL, Wells GA, Parkash R, et al. Ventricular tachycardia ablation vs escalation of antiarrhythmic drugs. N Engl J Med. 2016. doi: 10.1056/NEJMoa1513614.