Non-Scar-Related and Purkinje-RelatedVentricular Tachycardiain Patients With StructuralHeartDisease: Prevalence, Mapping Features, and Clinical Outcomes.

Abstract

This study sought to evaluate the prevalence, mapping features, and ablation outcomes of non-scar-relatedventricular tachycardia (NonScar-VT) and Purkinje-related VT (Purkinje-VT) in patients with structural heart disease. VT in structural heart disease is typically associated with scar-related myocardial re-entry. NonScar-VTs arising from areas of normal myocardium or Purkinje-VTs originating from the conduction system are less common. We retrospectively analyzed 690 patients with structural heart disease who underwent VT ablation between 2013 and2017. A total of 37 (5.4%) patients (16 [43%] with ischemic cardiomyopathy, 16 [43%] with nonischemic dilated cardiomyopathy, and 5 [14%] others) demonstrated NonScar/Purkinje-VTs, which represented the clinical VT in 76% of cases. Among the 37 VTs, 31 (84%) were Purkinje-VTs (28 bundle branch re-entrant VT). The remaining 6 (16%) VTs were NonScar-VTs and included 4 idiopathic outflow tract VTs. A total of 16 patients had prior history of VT ablations: empirical scar substrate modification was performed in 6 (38%) patients and residual inducibility of VT had not been assessed in 7 (44%). In all 37 patients, the NonScar/Purkinje-VT was successfully ablated. After a median follow-up of 18months, the targeted NonScar/Purkinje-VT did not recur in any patients, and 28 (76%) of patients were free from any recurrent VT episodes. NonScar/Purkinje-VTs can be identified in 5.4% of patients undergoing VT ablation in the setting ofstructural heart disease. Careful effort to induce, characterize, and map these VTs is important because substrate-based ablation strategies would fail to eliminate these types of VT.