Background Although percutaneous transluminal septal myocardial ablation (PTSMA) has been considered to be a new interventional technique to treat patients with hypertrophic obstructive cardiomyopathy (HOCM), few studies have reported their long term efficiency. The aims of this study were to investigate electrocardiographic date and the long term outcomes in follow-up.

Methods This study included 66 patients (36 males, 48.6 ± 12.4 years) in our hospital who were treated using PTSMA from October 2001 to October 2012. The indication for PTSMA was restricted to symptomatic patients with maximal LVOTG ≥50 mm Hg under basal conditions or ≥70 mm Hg with provocative manoeuvres or after extrasystole. Alcohol was injected to the suitable septal branch. Clinical and echocardiogrphic follow-up date (1 month, 6 month, and every year) was completed for all patients.

Results The average follow-up duration was [(41.0 ± 34.0)months, range, (12–144) months]. The average septal thickness 6 months after operation were significantly lower than the preoperative one [(17.6 ± 3.3)mm vs (19.2 ± 3.7) mm, p = 0.032], and the long term septal walls were ever thicker [(16.6 ± 4.0) mm vs (19.2 ± 3.7) mm, p = 0.015]. The average left ventricular outflow tract (LVOT) 6 months after operation were significantly lower than the preoperative one [(17.5 ± 1.6) mm vs (16.0 ± 1.4) mm, p = 0.002], and the long term LVOT were ever wider [(19.0 ± 3.0) mm vs (16.0 ± 1.4) mm, p <0.001]. The average left ventricular outflow tract gradient (LVOTG) 6 months after operation were significantly lower than the preoperative one [(30.0 ± 14.7)mm Hg vs (107.0 ± 49.6)mm Hg, p <0.001], and the long term LVOT gradients were ever lower [(29.7 ± 25.4)mmHg vs (107.0 ± 49.6)mmHg, p <0.001]. There were 40 patients returned routinely for checkups. During the follow-up period after operation, 1 all-cause deaths and 1 cardiac death occurred. There were 7 patients in NYHA classification II-III; they had sense of suppression or pain in the chest. There were 7 patients had right complete heart block, however, no patient had syncope or resuscitation. There was no case of heart transplantation, premature ventricular extrasystole, post interventional sustained ventricular tachycardia, or other arrhythmias.

Conclusions In this study, percutaneous transluminal septal myocardial ablation reduces septal thickness and LVOTG, as well as improves clinical symptoms with the long term follow-up.