In patients with structural heart disease (SHD) undergoing a first ablation for scar-related ventricular tachycardia (VT), during sinus rhythm without VT induction, there was a low rate of procedure-related complications and early mortality, according to a study published Oct. 26 in a special issue of JACC: Clinical Electrophysiology focused on VT.

The prospective, observational study conducted at six centers in Spain by Juan Fernandez-Armenta, MD, PhD, et al., examined the safety and short- and long-term outcomes of VT substrate ablation during stable rhythm (sinus or paced), using scar dechanneling, in patients with SHD and sustained monomorphic VT documented by ECG or ICD recording.

A total of 412 consecutive patients (92% men, mean age 64 years) were studied; two-thirds had ischemic cardiomyopathy, nearly 14% had arrhythmogenic right ventricular cardiomyopathy and the remainder had nonischemic cardiomyopathy. In the six months preceding the ablation, patients had a median of four VT episodes, and 32.3% had arrhythmic storm or incessant VT. Preprocedural imaging was obtained in 61% of patients, and epicardial access was performed in 31%.

The results showed that after substrate-guided ablation, 74% of patients had no inducible VT with the entire procedure completed during stable rhythm. Procedure-related complication rate was 6.5%, including one death (0.2%). Only four patients (0.97%) had complications related to hemodynamic decompensation.

At one year, the primary endpoint of ventricular arrhythmia-free survival was 82.5% after one procedure and 87.8% after n procedures. Early 30-day mortality after first VT ablation was 1.7%. Overall survival was 95.8% at one year and 88.6% at three years.

Independent predictors of overall survival based on multivariable analysis were age ≥70 years (hazard ratio [HR], 4.95; p<0.001), chronic obstructive pulmonary disease (HR, 2.37; p=0.008), left ventricular ejection fraction <30% (HR, 2.43; p=0.002), and incomplete substrate ablation (HR, 2.37; p=0.026).

The authors add that VT ablation based on substrate elimination during stable rhythm is safe and effective and has reproducible results and that hemodynamic decompensation was uncommon, with a low rate of early mortality and procedure-related complications. However, they conclude that randomized studies will be needed to assess the safety and efficacy of this strategy.

In an accompanying editorial comment, John Sapp, MD, writes, "Induction of VT at the outset of a procedure may provide further physiologic information, but its role has diminished to permitting more aggressive concentration of ablative effort on targets with higher specificity, and is particularly useful for hemodynamically tolerated VT." He adds that "the observations by Fernandez-Armenta, et al., provide reassurance that omitting initial induction is safe and reasonable for most patients. Induction testing at the end of a procedure remains useful for identification of residual substrate and to estimate prognosis when it appears clinically safe to do so."

Read the full VT focused special issue of JACC: Clinical Electrophysiology.

Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Heart Failure and Cardiomyopathies, Implantable Devices, Genetic Arrhythmic Conditions, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias

Keywords: Middle Aged, Arrhythmogenic Right Ventricular Dysplasia, Cicatrix, Stroke Volume, Ventricular Function, Left, Tachycardia, Ventricular, Cardiomyopathies, Arrhythmias, Cardiac, Prospective Studies, Registries, Prognosis, Pulmonary Disease, Chronic Obstructive, Electrocardiography, Electrophysiology

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