Abstract:

Objective To study the relationship between Noble grade and distribution of myocardial bridge and atherosclerosis. Methods The clinical data of 192 patients with myocardial bridge diagnosed by coronary artery angiography were retrospectively analysed. The clinical symptoms, electrocardiographic and echocardiographic findings were analysed to explore the relationship between Noble grade and distribution of myocardial bridge and atherosclerosis, and the outcomes of medical treatment were also investigated. Results The positive rate of myocardial bridge detected by coronary artery angiography was 10.2%, which was usually observed in the middle part of left anterior descending coronary artery. All the patients with grade 3 of Noble grade experienced chest pain or palpitation, 43.8% had ischemic ST-T changes on electrocardiogram, and 37.5% had abnormal segmental ventricular wall on echocardiography. However, patients with Noble grade 1 and 2 did not have ischemic ST-T changes on electrocardiogram or abnormal segmental ventricular wall on echocardiography. The prevalence of atherosclerosis in proximal coronary artery of myocardial bridge was significantly higher than those of mural coronary artery and distal coronary artery (P<0.05）. Furthermore, the prevalence of atherosclerosis in proximal coronary artery had the tendency to increase with the grade of myocardial bridge (P<0.0001). For patients with myocardial bridge, those with presence of symptoms were more frequently treated with β-receptor blocker, calcium antagonist and β-receptor blocker+calcium antagonist than those with absence of symptoms (80.0% vs 11.4%, 91.1% vs 15.9% and 62.2% vs 4.5%, respectively) (P<0.01）. Conclusion The symptoms of chest pain or palpitation usually occurred in patients with grade 3 of myocardial bridge, while the proximal coronary artery of myocardial bridge is prone to atherosclerosis, and β-receptor blocker and calcium antagonist are predominant drugs in the treatment.

Key words: myocardial bridge, coronary artery angiography, electrocardiogram, echocardiography, atherosclerosis