Clinical Analysis Of Myocardial Bridge

ObjectiveUsually,the coronary vessels course over the epicardial surface of the heart but may dip into the myocardium for varying lengths and then reappear on the heart's surface. coronary myocardial bridge(CMB) occurs when a band of cardiac muscle overlies an intramural segment of a coronary artery, the intramural segment being referred to as a (?)unneled? artery. Coronary angiograms can reveal the milking effect or systolic narrowing induced by significant myocardial bridging of a coronary artery. Regarded for long as innocent anatomic variants , CMB have been subsequently acknowledged as potential causes of unstable angina,acute myocardial infarction, life-threatening cardiac arrhythmias and sudden cardiac death in a particular condition. However,which clinical features of CMB will increase the morbidity of ischemic heart disease is unknown. Because of incomplete understanding of the pathophysiology of CMB,their clinicalsignificance has been the subject of debate for the last quarter century. As a result,the treatment options is still controversial.To study the clinic features of CMB and to evaluate the clinical significance of complicating atherosclerotic stenosis before CMB will provide a better therapeutic options of this intriguing clinical entity.MethodsData of 102 CMB from 1296 patients in our hospital during one year diagnosed by coronary angiography was analyzed retrospectively, then divided into two groups by whether there was atherosclerotic stenosis before myocardial bridge and compared the age, gender, Noble grading, cardiac functional grading,cardiac diastolic function,level of blood glucose,blood fat,cardiothoracic ratio and outpatient symptomatic relief proportion Between two groups.ResultsThe incidence of CMB was 7.9 %.the percentage of CMB located the left anterior descending coronary artery was 86.3%. The gender ratio was 73: 29 and the mean age was (60.10? 1.14) years. 38 cases had complicated atherosclerotic stenosis before myocardial bridge. 10 cases had concomitant Acute myocardial infarction and 13 cases complicated Unstable pectoris angina. Dividing the patients into two groups by whether there was atherosclerotic stenosis before CMB, they were simple CMB group(n=51 )and complex CMB group(n=38). complex CMB group more easily result in angina pectoris and acute myocardial infarction than simple CMB group(P<0.05).Between the twogroups,no significant difference was found about the age, gender, Noble grading, cardiac functional grading, cardiac diastolic function, level of blood glucose and blood fat (P>0.05), but There was significant difference in cardiothoracic ratio and outpatient symptomatic relief proportion(P<0.01).ConclusionThe clinical features of CMB diagnosed by coronary angiography are variable. Most of the patients with myocardial bridge are asymptomatic,but having pre-CMB atherosclerotic stenosis may result in ischemic heart disease , such as angina pectoris and myocardial infarction.Symptomatic patients must be treated.Medical therapy should be the first and principal strategy,and interventions should be limited patients with refractory angina despite medical therapy.CMB patients with pre-CMB atherosclerotic stenosis should be treated actively including stent implanting.