Symptomatic myocardial bridging: a frequently occurring coronary variation can cause severe myocardial ischaemia in affected children with underlying cardiac conditions.

Myocardial bridging is a congenital coronary artery anomaly in which the coronary artery has a partly "tunnelled" intramyocardial course. This tunnelling leads to compression of the affected vessel segment during ventricular systole. It is considered to be a benign variation of the norm in about 25% of the population caused by an aberrancy of embryologic coronary development. The bridging is also thought to cause severe cardiac conditions in a few of those affected. The series of six young patients presented here is the largest series so far to report on symptomatic myocardial bridging in children with different underlying heart diseases. All patients recently presented to our centre with signs of myocardial ischaemia. They subsequently underwent coronary angiography, which revealed myocardial bridging of the ramus interventricularis anterior. In all patients, therapy with β blockers was started to reduce heart rate and myocardial contractility. β Blocker treatment was also given in order to prolong diastole and improve coronary artery blood flow. Two patients underwent surgical exposure of the involved coronary segment: a 2-year-old boy because of recurrent, severe myocardial ischaemia in combination with a reduction of general health, changes in ST-segments, and the presence of a dilative cardiomyopathy; and a 13-year-old girl because of evidence of myocardial ischaemia during exercise testing after surviving sudden cardiac death. Surgery was successful and recovery was complete and uneventful. The presented series shows that myocardial bridging can be symptomatic and may require urgent treatment and even surgical intervention in early childhood in rare cases.