OBJECTIVETo retrospectively summarize the effect of non-medical therapies for pediatric patients with hypertrophic obstructive cardiomyopathy (HOCM).

METHODSFrom Nov. 2008 to Jun. 2010, 4 children with drug-refractory HOCM were admitted to our hospital. Their ages were 14, 7, 9 and 6 years old, respectively. Their body weights were 38, 17, 21.5 and 17 kg, respectively. Before operation, the pressure gradients over left ventricular outflow tract (LVOTG) were 60, 147, 58 and 114 mm Hg (1 mm Hg = 0.133 kPa), respectively. And mitral regurgitation (MR) areas were 2.2, 7.3 cm(2) and 2.9 cm(2), respectively, except that it was trivial in one case. Percutaneous transluminal septal myocardial ablation (PTSMA) was performed in case 1 and 2. Septal myectomy (SM) was performed in case 3 and 4. Follow-up was first performed right after operation or before discharge, then 1 month, 3 months, 6 months, and 12 months after operation, and then once a year. The follow-up period was 1 - 18 (9.3 ± 8.1) months.

RESULTSAll patients experienced relieved symptoms. Three of them had their NYHA functional class improved except case 2. Echocardiography revealed that LVOTGs right after operations were 38, 79, 20 and 0 mm Hg, respectively, suggesting significant improvement of left ventricular outflow tract obstruction (LVOTO) in all patients. During follow-up, case 2 suffered from recurrence of LVOTO, while the other 3 cases showed sustained relief. In the last follow-up, the LVOTGs of the four patients were 19, 168, 16 and 0 mm Hg, respectively. Echocardiography also revealed that MRs of all patients were significantly reduced, even in case 2 whose LVOTG rebounded, with no recurrence during follow-up. Severe complications were absent, such as ventricular septum perforation, cardiac tamponade, ventricular tachycardia or ventricular fibrillation. No one suffered from complete heart block. Transient complete right bundle branch block (CRBBB) was observed in case 1 after PTSMA and converted to intraventricular block after 1 month. Complete left bundle branch block (CLBBB) was present in both case 3 and 4, who received SM. In case 4, it converted to intraventricular block after 1 month while in case 3 CLBBB persisted.

CONCLUSIONSThe initial experience showed that PTSMA and SM were safe and effective for drug-refractory symptomatic HOCM children, with satisfactory short-term results. Further studies are needed to evaluate the long-term results and complications.