'Scar-Based' VT Ablation Bests Standard Technique: VISTA

Marlene Busko

December 23, 2015

AUSTIN, TX — Arrhythmia recurrences were significantly curtailed and the risk of hospitalization or death dropped in patients with recurrent ventricular tachycardia (VT) who underwent catheter ablation aimed at the arrhythmia substrate (ie, scar) rather than by the conventional technique, in a small randomized trial [1]. The study population consisted of patients with implantable cardioverter defibrillators (ICDs) and drug-refractory, hemodynamically stable VT despite antiarrhythmic drug therapy.

At a 12-month follow-up, only 15% of the patients who underwent extensive ablation vs 48.3% of the patients who had limited ablation had recurrent VT, the study's primary end point (P<0.0001). Patients who had the more extensive ablation also had lower rates of the combination of mortality and rehospitalization and a lesser need for antiarrhythmic drugs.

These findings by Dr Luigi Di Biase (Texas Cardiac Arrhythmia Institute, Austin Texas) and colleagues, from the Ablation of Clinical Ventricular Tachycardia versus Addition of Substrate Ablation on the Long Term Success Rate of VT Ablation (VISTA) study, were published in the December 29, 2015 issue of the Journal of the American College of Cardiology.

This is the first randomized trial comparing the two procedures, and the extensive ablation was done in sinus rhythm, Di Biase stressed to heartwire from Medscape. The study findings "should prompt a change in how these procedures are done," according to coauthor Dr Andrea Natale (Texas Cardiac Arrhythmia Institute).

In an audio commentary, JACC editor in chief Dr Valentin Fuster (Icahn School of Medicine at Mount Sinai, New York) said that the superiority of extensive ablation was "striking." Interestingly, "the extensive approach works in ventricular tachycardia, but thus far this does not appear to be the case in atrial fibrillation," he noted.

"The current study convincingly demonstrates that more extensive ablation is more effective," Dr Roderick Tung (University of Chicago, IL) and Dr Hans Kottkamp (Hirslanden Hospital, Zurich, Switzerland) echo in an accompanying editorial[2]. "Randomized, multicenter studies in VT ablation are few to date, and the present study sets the tone for the prospective collaborative work that lies ahead in this evolving field."

Comparing Two Ablation Strategies

From 2009 to 2013, VISTA enrolled 118 patients who had received an ICD and had recurrent stable monomorphic VT episodes that were symptomatic or required ICD shocks despite antiarrhythmic drugs. The patients were randomized to receive extensive substrate-based ablation (58 patients) or clinical, more limited ablation (60 patients) in seven centers.

The mean extensive-ablation procedure took 4.2 hours vs 4.6 hours for the mean limited-ablation procedure (P=0.14). At 12 months after the procedure, the more extensive ablation was associated with a significantly lower rate of recurrence of VT and a lower risk of being rehospitalized for VT (12.1% vs 32%).

There was no significant difference in the number of patients who died in the extensive- vs limited-ablation groups (8.6% vs 15.0%). However, the combined end point of mortality and rehospitalization was significantly lower in patients who had undergone extensive ablation.

Risk of 12-Month Outcome, Extensive vs Limited Ablation

Outcome HR (95% CI) P
VT recurrence rate 0.26 (0.11–0.61) <0.001
All-cause mortality 0.54 (0.17–1.82) 0.21
Arrhythmia-related rehospitalization 0.31 (0.13–0.78) 0.014
Combined mortality and rehospitalization 0.32 (0.17–0.61) 0.003

After adjustment for covariates, extensive ablation was associated with a 67% lower risk of recurrence of VT (HR 0.33; 95% CI 0.13–0.81; P=0.014). Periprocedural complications were similar in both groups (P=0.61).

Tung and Kottkamp note that this study enrolled patients with drug-refractory hemodynamically tolerated VT, so the findings are not applicable in patients with only unstable ventricular tachycardia, which comprise about 40% of all patients referred for ablation.

Di Biase is a consultant for Biosense Webster, Boston Scientific, St Jude Medical, Janssen, and Stereotaxis; has received speaker honoraria/travel expenses from Medtronic, Atricure, EPiEP, and Biotronik; and has received travel/compensation from Pfizer. Natale has received speaker honoraria from Boston Scientific, Biosense Webster, St Jude Medical, Biotronik, and Medtronic and is a consultant for Biosense Webster, St Jude Medical, and Janssen. Disclosures for the other coauthors are listed in the article. Kottkamp is a consultant for Biosense and Kardium. Tung has no relevant financial relationships.

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