Successful Radiofrequency Catheter Ablation of Monomorphic Ventricular Tachycardia in a Patient of Hypertrophic Obstructive Cardiomyopathy with an Apical Aneurysm: A Case Report

A 56-year-old man suffered from hypertrophic obstructive cardiomyopathy (HOCM) associated with an apical aneurysm and monomorphic ventricular tachycardia (VT). The patient was transferred to our hospital for the purpose of the electrophysiologic study (EPS) and radiofrequency catheter ablation. In the EPS, clinical VT could be induced only during isoproterenol infusion but it lasted only for a few seconds. Because the activation map using the contact mapping system (Ensite NavXTN) was considered to be difficult, the substrate map underwent. The electrical potential could hardly be recorded inside the apical aneurysm. Because of plural slow conductions around the aneurysm, the earliest activation site was difficult to be identified by the activation map. The pace mapping conducted in the boundary area between the intact cardiac muscle and the aneurysm exhibited a perfect pace map at postero-lateral edge of the aneurysm. The point radiofrequency catheter ablation was performed at this site, and additional circumferential ablation was performed to isolate the scar area within apical aneurysm from the intact ventricular muscles. After these ablation procedures, the VT became un-inducible even during isoproterenol infusion and no recurrence was observed for 18 months.