OBJECTIVETo follow up the electrocardiographic and cardiac autonomic function changes after percutaneous transluminal septal myocardial ablation (PTSMA) in patients with hypertrophic obstructive cardiomyopathy (HOCM).

METHODSBaseline, 3 days and 3 years post procedure 12-lead electrocardiographic and 24-hour Holter electrocardiographic recordings including PR interval, QRS duration, cardiac conduct block, QT, QTd, QTcd, JT, JTd, JTcd, heart rate variability (HRV) data (SDNN, SDANN, HF, rMSSD, PNN50, LF, HF, LF/HF) were analyzed in 26 patients with HOCM receiving PTSMA.

RESULTThe PTSMA procedure was successful in all 26 patients. One patient developed complete atrioventricular block requiring permanent pacing. The PR interval was significantly prolonged 3 days after ablation and recovered 3 years post procedure. Right bundle branch block was seen in all patients 3 days after post procedure and in 24 patients at 3 years post procedure. The QRS duration was significantly prolonged at 3 days and 3 years post procedure. There was persistent QT interval prolongation up to 3 years and transient QTd, QTcd prolongation (prolonged at 3 days and returned to baseline at 3 years after ablation) while JT, JTd, JTcd were not significantly changed after PTSMA. LF, HF, rMSSD and PNN50 were significantly increased while LF/HF, SDNN, SDANN remained unchanged post procedure.

CONCLUSIONPTSMA is a safe and effective therapy option for HOCM. Right bundle branch block was the main electrocardiographic change post procedure and PTSMA could partly restore the heart sympathovagal balance by improving vagal activity.