Ventricular Tachycardia Substrate Ablation During Sinus Rhythm Associated With Few Complication, Low Mortality

Substrate ablation during sinus rhythm (SR) performed to avoid multiple ventricular tachycardia (VT) induction was found to be associated with low rates of procedural complications and early mortality, according to the results of a prospective multicenter registry published in the American College of Cardiologists: Clinical Electrophysiology.

A total of 412 patients (mean age, 64±14 years; 91.3% men) who underwent scar-related VT ablation at 6 centers across Spain were recruited for this study. A transseptal approach was used in which a 3.5-mm-tip open-irrigated ablation catheter or multipolar catheter were used for mapping. An irrigation rate of 26 to 30 mL/min was used for ablation of the arrhythmogenic substrate during SR. Procedures were finished when a complete elimination of any electrogram abnormality was achieved and there was noninducibility of any VT.

Success was achieved when sustained monomorphic VT could not be induced. Incomplete ablation was defined as persistence of electrogram abnormalities, inaccessible midmyocardial septal scar, or inaccessible epicardial substrate. Patients were assessed every 6 months. VT recurrence was defined as sustained VT for >30 seconds.

In this cohort, mean left ventricular ejection fraction was 38%±13%, 65.8% had ischemic cardiomyopathy, 20.6% nonischemic cardiomyopathy, 13.6% had arrhythmogenic right ventricular cardiomyopathy, 64.3% hypertension, and 25.2% diabetes.

Percutaneous pericardial access was achieved in 75% of patients with arrhythmogenic right ventricular cardiomyopathy, 40% of those with nonischemic cardiomyopathy, and 18.45% of patients with ischemic cardiomyopathy. A multipolar catheter was used in 24% of patients, and no patient required a left ventricular assist device.

Induced or spontaneous VT occurred in 15.5% of patients during substrate mapping, leading to VT termination. A median of 834±1592 points were collected in electroanatomic maps. An average of 8.12±11 hidden slow conduction electrographs were detected per patient and 4±8 residual electrograph abnormalities. Average radiofrequency time was 21±14 minutes.

Procedural success was achieved for 75.2% of patients. VT was induced in 16.1% of patients with arrhythmogenic right ventricular cardiomyopathy, in 34.1% of patients with ischemic cardiomyopathy, and in 23.6% of patients with ischemic cardiomyopathy (P =.042).

Procedural-related complications occurred in 6.8% of patients. The 30-day mortality rate was 1.7%, and 15.3% at 24 months. Survival was 95.8% at 1 year and 88.6% at 3 years.

Mortality was higher among patients ages ³70 years (hazard ratio [HR], 4.95; 95% CI, 2.59-9.47; P <.001), those with left ventricular ejection fraction <30% (HR, 2.43; 95% CI, 1.37-4.33; P =.002), with chronic obstructive pulmonary disease (HR, 2.37; 95% CI, 1.24-4.52; P =.008), and incomplete substrate ablation (HR, 2.37; 95% CI, 1.24-4.52; P =.026).

At 1 year, 82.5% of patients who underwent a single procedure had VT-free survival which was comparable across treatment center (P =.445), and was not associated with global mortality (P =.212), or cardiomyopathy type (P =.130).

A major limitation of this study was the absence of a comparative group undergoing a different ablation strategy.

These data indicated that substrate ablation during SR which avoided multiple VT inductions had low rates of procedural-related complications, early mortality, or recurrence.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.

Reference

Frenandez-Armenta J, Soto-Iglesias D, Silva E, et al. Safety and outcomes of ventricular tachycardia substrate ablation during sinus rhythm: A prospective multicenter registry. JACC Clin Electrophysiol. 2020;6(11):1435-1448. doi:10.1016/j.jacep.2020.07.028