Among patients with ischemic cardiomyopathy and ventricular tachycardia (VT), catheter ablation as a first-line strategy over antiarrhythmic drugs (AAD) was associated with a lower risk of the primary outcome, according to results of the VANISH2 trial presented at AHA 2024 and simultaneously published in NEJM.

John Lewis Sapp, MD, et al., randomized patients with an ICD at 22 centers in Canada, the U.S. and France 1:1 to either catheter ablation (203 patients) or treatment with sotalol or amiodarone (213 patients). Most patients were men (~95%) and about 68 years old. All had a history of a myocardial infarction (MI) and a VT event within the previous six months while not being treated with AADs. More patients in the ablation arm were likely to have undergone PCI and in the AAD arm more were taking antiplatelet therapy.

The primary composite endpoint was death from any cause during follow-up and after 14 days post randomization appropriate ICD shock, VT storm, or treated sustained VT below the detection of the ICD. Results showed that at a median follow-up of 4.3 years, a primary endpoint event occurred in 103 (50.7%) of patients in the catheter ablation arm and 129 (60.6%) in the AAD arm (hazard ratio, 0.75; 95% CI, 0.58-0.97; p=0.03).

"This difference appeared to be due to a lower number of appropriate ICD shock events and episodes of treated sustained [VT] below the detection limit of the ICD (both after 14 days) in the catheter ablation group," write Sapp and colleagues.

A total of 1,383 episodes of appropriate ICD shock or antitachycardia pacing occurred in the catheter ablation arm vs. 2,195 episodes in the AAD arm, with a mean difference of –4.22 events per person-year. Looking at components of the primary endpoint, death from any cause occurred in 45 (22.2%) vs. 54 (25.4%) of patients in the catheter ablation vs. AAD arms, respectively. Appropriate ICD shock occurred in 60 (29.6%) vs. 81 (38.0%), VT storm in 44 (21.7%) vs. 50 (23.5%), and treated VT below the detection limit of the ICD in nine (4.4%) vs. 35 (16.4%). There were two deaths in the catheter ablation arm due to procedural complications and one death in the AAD arm due to pulmonary toxicity attributed to the AAD.

Although the study could not confirm if ablation worked better than medication to reduce each outcome tracked, the researchers found that overall, the differences favored ablation. The study also did not determine which patients with particular characteristics would benefit more from one treatment or the other.

"Although the study was not large enough to show a statistically definitive effect on all of the parameters that are important to patients and physicians, patients treated with ablation also had fewer ICD shocks for VT, fewer ICD treatments, episodes of three or more VT in a single day and fewer VT episodes not detected by their ICD," Sapp said. "For people who have survived a heart attack and developed VT, our findings show that performing a catheter ablation to directly treat the heart's abnormal scar tissue causing the arrhythmia, rather than prescribing heart rhythm medications that can affect other organs as well as the heart, provides better overall outcomes. These results may change how heart attack survivors with ventricular tachycardia are treated."