Myocardial bridging of coronary arteries associated with an impending acute myocardial infarction

A 57-year-old woman developed severe substernal chest pain radiating to the left arm accompanied by pallor and marked diaphoresis. These symptoms appeared at rest, lasted 45 minutes, and terminated spontaneously. The patient had been treated for mild hypertension during the last 6 months. An ECG tracing obtained at the beginning of treatment was unremarkable. However, an ECG tracing recorded shortly after the end of the symptoms showed T-wave inversion in all anterior leads. Coronary arteriography was then performed and showed no fixed obstructive coronary artery disease. Nonetheless, a lengthened and constricted myocardial bridging of both the left anterior descending coronary artery and its major diagonal branch was detected. Also, the left anterior descending coronary artery was observed to be very short, terminating before the cardiac apex. The left ventricle was hypertrophied. The patient was treated with a beta-blocking agent which eliminated all symptoms. An ECG tracing obtained about three months after the onset of the clinical picture was normal. Our findings suggest that marked myocardial ischemia at rest does occur in patients having myocardial bridges under special circumstances, such as lengthened and constricted myocardial bridging of a short coronary artery which supplies a hypertrophied ventricle. This anomaly should be taken into account as a possible cause of a threatened myocardial infarction, which may be successfully treated with a beta-blocking agent.