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VISTA: Substrate-based ablation improved outcomes in patients with VT
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SAN FRANCISCO — New data from the VISTA study suggest that substrate-based ablation is superior to ablation of the clinical ventricular tachycardia in patients with ischemic cardiomyopathy presenting with stable ventricular tachycardia.
VISTA was designed to compare the effectiveness of the two ablation approaches in patients with stable ventricular tachycardia (VT) and ischemic cardiomyopathy, Luigi Di Biase, MD, PhD, FHRS, from Texas Cardiac Arrhythmia Institute at St. David’s Medical Center and Albert Einstein College of Medicine at Montefiore Medical Center, New York City, said during a press conference at the Heart Rhythm Society Annual Scientific Sessions. Previous nonrandomized studies had suggested a substrate-based approach might produce better outcomes; however, this hypothesis had not been tested in a randomized clinical trial, he said.
Luigi Di Biase
The researchers randomly assigned 60 patients to ablation of the stable clinical VTs only and 58 patients to substrate-based ablation, in which ablation is extended throughout the entire scar to target all abnormal electrocardiograms. Mean left ventricular ejection fraction did not differ between the two groups at baseline (P=.8).
The primary endpoint was freedom from any VT at 12 months. At 12 months, 84.5% of patients in the substrate-based ablation group were free of any clinical ventricular arrhythmia vs. 51.7% of the VT-ablation-only group (P<.001).
After adjustment for age, sex and LVEF, the researchers found that ablation of clinical VT alone was associated with a higher recurrence of VT (HR=3.09; P=.014) vs. substrate-based ablation.
“We also found that the ablation of the substrate reduced significantly the combined [secondary] endpoint of rehospitalization and mortality in this population,” Di Biase said. This endpoint was reached by 46.7% of the VT-ablation-only group vs. 20.7% of the substrate-based ablation group (P=.003), he said.
Predictors of mortality included advanced NYHA class and very low LVEF. Although type of ablation was not a predictor of mortality, it was a predictor of success rate and follow-up ablation procedure, Di Biase said.
The groups did not differ in procedural time (P=.14) and fluoroscopy time (P=.13), but radiofrequency time was longer in the substrate ablation group (68 minutes vs. 35 minutes; P<.001). However, patients in the VT-ablation-only group were more likely to use antiarrhythmic drugs 12 months after ablation (P<.001).
Adverse events included one artero-venous fistula and one pericardial effusion in the VT-ablation-only group and two pericardial effusions in the substrate-based ablation group. – by Erik Swain
For more information:
Di Biase L. Abstract LB01-03. Presented at: Heart Rhythm Society Annual Scientific Sessions; May 7-10, 2014; San Francisco.
Disclosure: Di Biase reports consulting for Biosense Webster, Hansen Medical and St. Jude Medical and receiving speaker honoraria from Atricure and Biotronik.