INTRODUCTIONLittle is known of the clinical significance of myocardial bridges, which may be recognised as the narrowing of the systolic coronary artery as seen in an angiography. In this study, our goal was to review the literature information about the anatomic aspects, the clinical manifestations and implications, and the angiographic characteristics.

MATERIALS AND METHODSThe angiographic data of 7200 adult patients undergoing coronary angiography were retrospectively analysed for the diagnosis of myocardial bridge. The main angiographic evidence of a myocardial bridge that we required was the narrowing of a systolic coronary artery resulting in at least 50% reduction of lumen diameter in comparison with the diastolic phase. All coronary angiograms were reviewed independently by at least 2 of the authors and the case was included only if there was a consensus that the myocardial bridge resulted in 50% narrowing or more.

RESULTSMyocardial bridge was present in 29 (0.4%) of the 7200 coronary angiographies. The location of the myocardial bridge was in the left anterior descending coronary artery in 28 cases (96.5%), and the left circumflex coronary artery in 1 case (3.4%). Myocardial bridge was most common in the middle segment of the left anterior descending coronary artery (78.5 %). Each of these patients with myocardial bridge was referred for angiography because of symptom of chest pain alone or symptom of chest pain, palpitations and dyspnoea. Of the 29 patients with myocardial bridge, 2 patients without any symptom, demonstrated ischaemia as assessed by Tc- 99m MIBI myocardial perfusion scintigraphy.

CONCLUSIONChest pain was the common reason for angiography in patients with myocardial bridge. The incidence of myocardial bridge may vary according to population. Myocardial bridge is more frequently found in the middle segment of the left anterior descending coronary artery.