OBJECTIVETo investigate the prognostic value of acute heart block (AHB) after percutaneous transluminal septal myocardial ablation (PTSMA) in patients with hypertrophic obstructive cardiomyopathy (HOCM).

METHODSNinety-four HOCM patients underwent PTSMA were included in this study. Twelve-lead electrocardiograms were obtained during and post PTSMA. Association between clinic events and incidence of post-PTSMA AHB was analyzed.

RESULTSAHB was induced in 26 patients by PTSMA and disappeared in 11 patients shortly post PTSMA, subacute intraventricular conduction disturbances was seen in 11 (42.3%), subacute I degrees AVB in 2 (7.7%) and subacute III degrees AVB in another 2 (7.7%) patients. Among 68 patients without AHB during PTSMA, intraventricular conduction disturbances was evidenced in 14 patients (20.6%), I degrees AVB in 2 (2.9%) and III degrees AVB in 1 patient (1.5%) after PTSMA. AHB patients with subacute heart block were associated with poor prognosis (conduction block duration was 42.00 h) while patients without AHB was associated with benign prognosis even with new onset of subacute heart block (conduction block duration was 7.33 h, P < 0.01).

CONCLUSIONPatients with AHB during PTSMA are at higher risk for subacute heart block, especially intraventricular conduction disturbances. AHB patients with subacute heart block were associated with poor prognosis and longer recovery time of conducting system.