Catheter ablation is better for ventricular tachycardia than increasing drug therapy

Patients with ventricular tachycardia (VT) who underwent catheter ablation had better outcomes than similar patients who received escalating doses of antiarrhythmic drugs, according to results from a large clinical trial published online May 6, 2016 in the New England Journal of Medicine.

VT is caused by scarring that occurs after a heart attack, and it carries a substantial risk of death. An implantable cardioverter defibrillator (ICD) as well as concomitant antiarrhythmic drug therapy can significantly reduce that risk.

But if VT recurs despite antiarrhythmic drug therapy, then the clinician and patient must choose either catheter ablation or an escalation in drug therapy.

“Until now, we really didn’t know what the best treatment was when our first-line drug therapy didn’t work as well as we’d hoped,” said the study’s principal investigator John L. Sapp, MD, Professor of Cardiology at Dalhousie Medical School, in Halifax, Nova Scotia, Canada.

To find out which was the best treatment, Dr. Sapp and colleagues enrolled 259 patients at 22 tertiary referral centers in Canada, the United States, Europe, and Australia. Each of these participants had prior heart attack, an ICD, and recurrent VT. Half were randomized to undergo ablation and half were assigned to receive escalated antiarrhythmic drug therapy.

During an average follow-up of about 28 months, the researchers found that catheter ablation was a better option for most patients. Results showed that more patients in the escalated-therapy group (68.5%) experienced the primary outcome (a composite of death, 3 or more documented episodes of VT within 24 hours, or appropriate ICD shock) than patients in the ablation group (59.1%).

“Ablation carries a bit more up front procedural risk, but high doses of the medications we use in an attempt to control VT tend to cause more issues in the long-term. The higher the dose, and the longer the strong antiarrhythmic drugs are administered, the higher the risk of adverse side effects,” said Dr. Sapp, who is also Director of the Heart Rhythm Service at the QEII Health Sciences Centre in Halifax, where the study was coordinated.

“Neither of the two treatments showed superiority with respect to mortality, perhaps because of the relatively high risk of death from non-arrhythmic causes,” the authors noted.

One limitation of the study was that it included patients with advanced cardiac disease who were given second-line therapy, the researchers acknowledged. Further study could show which treatment is a better first-line therapy for scar-related VT.