The VANISH trial shows that compared to an escalation in antiarrhythmic drug therapy, a catheter ablation confers better outcomes in terms of survival and disease prognosis in patients with recurrent ventricular tachycardia despite the placement of an implantable cardioverter-defibrillator (ICD). The findings were published in the New England Journal of Medicine on May 5, 2016.
Despite antiarrhythmic drugs and an ICD, ventricular tachycardia is common among survivors of myocardial infarction. Ventricular tachycardia, caused by the scarring associated with myocardial infarction, substantially increases the risk of death. This risk is markedly reduced by the placement of an ICD. ICDs successfully terminate ventricular tachycardia and are currently implanted in more than 100,000 patients in the United States per year. However, recurrent arrhythmias, despite the placement of an ICD, are common among such patients, reducing the quality of life, and increasing the risk of hospitalization, heart failure and death.
Several randomized controlled trials have shown the efficacy of antiarrhythmic therapy (sotalol, amiodarone) in controlling ventricular arrhythmias but the most effective approach to the management of the condition remains a mystery so far.
The VANISH trial may be a step towards finding an effective management to the problem.
The VANISH trial was a randomized, controlled trial conducted in 22 tertiary centers where catheter ablation was routinely performed in the United States, Canada, England and Australia.
Patients were eligible for inclusion in the trial if they had a history of a myocardial infarction, placement of an ICD and a recurrence of ventricular arrhythmias despite antiarrhythmic therapy in the last six months. Patients were randomly assigned into two groups i.e., escalated therapy vs catheter ablation.
Of 259 patients enrolled in the trial, 127 received escalation therapy whereas 132 were randomized into the catheter ablation group.
Patients in the escalation therapy were treated with amiodarone (class III antiarrhythmic agent) or amiodarone plus mexelitine (class IB antiarrhythmic agent; sodium-channel blocker).
Patients in the ablation group underwent the standardized procedure within 14 days of randomization. To minimize bias, standardized protocols were followed.
The primary outcome of the trial was death or ventricular tachycardia storm (three-to-four documented episodes of tachycardia within 24 hours), or ICD shock after 30 days of treatment. The secondary outcome included any of the primary outcome components plus adverse effects i.e., related to medical therapy or the procedure.
The patients were enrolled from July 2009 to November 2014. Patients were followed for approximately 28 months. The follow-up was completed in November 2015.
All patients in the escalation group received therapy as planned; however, four withdrew before the primary outcome could be reached, one underwent a heart transplantation, and 11 subsequently went for a catheter ablation.
Whereas out of 132 patients in the ablation group, 129 underwent the procedure, one died of a heart attack, one died of sepsis, and the last withdrew from the trial. The statistical analyses were conducted according to intention-to-treat principle.
In the ablation group, primary outcome was reported in 78 patients (59.1%), whereas in the escalation therapy group, 87 patients (68.5%) reached the primary outcome. As can be seen, the rate of primary outcome was markedly lower in the ablation group, as compared to the escalation therapy group.
Patients in the ablation group had a reduction in the rates of appropriate shocks, episodes of ventricular tachycardia storms, and death.
The incidence of ventricular tachycardia storm was 24.2% (32 patients) and 33.1% (42 patients) in the ablation and therapy escalation groups respectively. Whereas appropriate ICD shock occurred in 50 (37.9%) and 54 (42.5%) patients in ablation and therapy escalation group respectively.
In the ablation group, 36 patients (27.3%) died, whereas the count was 35 (27.6%) in the therapy escalation group.
As for secondary outcomes, the rate was higher in the escalation therapy group.
The trial was funded by the Canadian Institute of Health Research.
Recurrent Ventricular Tachycardia
Recurrent ventricular tachycardia is a common but manageable condition in patients with ischemic cardiomyopathy with an ICD placement. There is a whole class of drug dedicated to treating arrhythmias. Patients with recurrent episodes of ventricular tachycardia are treated most commonly with amiodarone – a class III antiarrhythmic agent.
Nonetheless, these patients remain at high risk of subsequent adverse events associated with the condition and the medical therapy, poor prognosis and death due to congestive heart failure.
Sudden cardiac arrest is the leading cause of death in the United States i.e., approximately 335,000 people lose their life to a myocardial infarction annually. Of these deaths, arrhythmias account for 88% of all the causes and ventricular tachycardia for 62%.
First used in 1960s, the catheter ablation therapy has revolutionized the treatment for arrhythmias. Many trials have found superiority of the ablation therapy for recurrent or refractory arrhythmias over the conventional pharmaceutical therapy.