Clinical and electrophysiological characteristics in patients with sustained monomorphic reentrant ventricular tachycardia associated with dilated-phase hypertrophic cardiomyopathy

Little is known about sustained monomorphic ventricular tachycardia (SMVT) associated with dilated-phase hypertrophic cardiomyopathy (DHCM). The purpose of this study was to clarify the clinical characteristics and effectiveness of catheter ablation for SMVTs in DHCM patients. Five patients with DHCM (mean age; 67.0 years old, five males) who underwent catheter ablation for drug-refractory SMVTs were included the study. Four of five patients suffered from electrical storm. When the endocardial ablation failed, epicardial and/or intracoronary ethanol ablation, or surgical cryoablation was performed. We reviewed all ablation procedures and electrocardiogram (ECG) of targeted SMVTs. A total of 13 SMVTs were targeted for ablation. Mechanism of all ventricular tachycardias (VTs) was diagnosed as reentry. Endocardial ablation successfully eliminated all VTs in two patients. The remaining three patients needed epicardial ablation, intracoronary ethanol ablation, and surgical cryoablation. All but one VT arose from the basal septum, basal anterior to anterolateral left ventricle (LV). Although the ECGs demonstrated similar features of idiopathic outflow or mitral annulus VTs reflecting the origins, there were characteristic multiple QRS deflections. Following the ablation, four (80) of the five patients are free from VT recurrence during 18 months of the follow-up period. In DHCM patients, VT circuits predominantly distributed in the basal septum and the basal anterior to anterolateral LV. In addition to the endocardial ablation, alternative approaches were required in some patients.