Clinical characteristics and therapies of hypertrophic cardiomyopathy combined with myocardial bridging

AIM: To summarize the clinical characteristics and therapies of hypertrophic cardiomyopathy (HCM) combined with myocardial bridging (MB). METHODS: The clinical characteristics and therapies were analyzed retrospectively in HCM patients combined with MB identified by echocardiographic or left ventriculography and coronary angiography. RESULTS: Seventy-eight MBs were found in 73 cases (11.9%) among the 612 HCM patients. Clinical presentations included chest distress and dyspnea in 31 patients, angina in 22 patients, cardiopalmus in eight patients, syncope and presyncope in eight patients and debilitation in two patients. Two patients were seen because of electrocardiographic abnormality. Among the patients were 28 nonobstructive HCM, 19 obstructive HCM and 26 apical HCM. The average length of MB was (9.8±4.5) mm. MB was located at the middle segment of the left anterior descending artery in 49 (62.8%) sites, at proximal-middle segment in two (2.6%) sites, at middle-distal segment in 11(14.1%) sites, at proximal segment in one (1.3%) site and at distal segment in 12 (15.4%) sites. Two (2.6%) MBs were found at the septal branch and one (1.3%) at the posterior descending branch. The degrees of compressed systolic narrowing were <50% at 31(39.7%) MBs, 50%-75% at 21 (26.9%) bridges and >75% at 26 (33.3%) bridges. Sixty-eight patients were treated with β-receptor blockers and five patients with calcium antagonists because of intolerance or contraindication to β-receptor blockers. The clinical follow-up periods were 3-20 (12.7±4.1) months and the rate of symptomatic relief was 75.3%. No statistical difference was observed between the therapeutic effects of the two drugs (76.5% vs. 60.0%). Patients with coronary artery disease (CAD) or atherosclerosis underwent long-term antiplatelet therapy with aspirin. Four cases of CAD were diagnosed by coronary angiography in whom four stents were implanted and all the target vessels were unrelated to MB. Six obstructive HCM patients with poor results from drug therapy were treated with percutaneous transluminal septal myocardial ablation. Clinical symptoms improved significantly after myocardial ablation and patients were alive during the 3- to 12-month (7.0±3.2) months follow-up. No patients underwent stent implantation or surgery because of MB. CONCLUSION: Both β-receptor blockers and calcium antagonists are optimal for HCM and MB. Obstructive HCM patients with poor results from drug therapy should be treated with percutaneous transluminal septal myocardial ablation. Stent implantation and lysis of MB are not recommended for isolated MB.