Midterm outcomes of percutaneous transluminal septal myocardial ablation in patients with hypertrophic obstructive cardiomyopathy refractory to medication

摘要

Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder characterized by severe asymmetric hypertrophy of the interventricular septum (IVS) in the absence of any other systemic or cardiac diseases. The predominant abnormal haemodynamics are caused by increased left ventricular outflow tract pressure gradient (LVOTG) and abnormal systolic anterior motion of mitral valve.1'2 Recently, there has been growing interest in injecting alcohol into the first major septal coronary artery of left anterior descending artery (percutaneous transluminal septal myocardial ablation, PTSMA) as an alternative to myectomy in patients with HOCM who remain symptomatic despite optimal medication including beta-adrenergic blocking agents, verapamil, and disopyramide. PTSMA is a new procedure which consists of inducing a localized myocardial infarct by ethanol infusion into septal branches of left anterior descending coronary artery. Scarring and thinning of the intra-ventricular septal (IVS) results in widening of the LVOT, and consequently, decrease of the pressure gradient and symptomatic improvement. The most severe complication after PTSMA procedure is complete heart block (3% — 5%) requiring permanent pacemaker. Several researchers have reported 15%—33% incidence of complete right bundle branch block (CRBBB). However, the implications of CRBBB remain unclear during followup period. The common occurrence of CRBBB at our beginning work in 1999 lead to the present study to document the longterm clinical importance of CRBBB following PTSMA procedure.