Three-vessel myocardial bridging: A possible cause of myocardial stunning

Update review on myocardial bridging: New insights

Myocardial bridging (MB) is a common congenital abnormality that remains asymptomatic in a large proportion of patients. The peak of clinical manifestation occurs during the third and fourth decades of life. MB provokes myocardial ischemia through different mechanisms including supply-demand mismatch, endothelial dysfunction, coronary microvascular dysfunction and external mechanical compression. The association between MB and atherosclerotic disease is controversial. Recent studies established a significant association of MB with myocardial infarction and non-obstructive coronary artery disease. The first line medical treatment is based on beta-blockers and calcium channel blockers. Ivabradine is used in second line therapy. Invasive approaches involving percutaneous coronary intervention, coronary artery bypass graft and myotomy are performed in patients with symptoms refractory to maximally tolerated medical treatment. The choice of revascularization technique depends on anatomical characteristics, clinical condition and physician experience. Available data derived from anecdotal evidence view the lack of randomized clinical trials.

Myocardial bridging presenting as myocardial ischaemia induced cardiac arrest: a case report

Background

Myocardial bridging is a congenital anomaly defined as a segment of epicardial coronary arteries running through the myocardium. Various complications related to myocardial bridging have been reported, but at present, cardiac arrest has rarely been reported.

Case presentation

We report one case of a patient who was successfully resuscitated from ventricular fibrillation cardiac arrest and was diagnosed with myocardial bridging accompanied by myocardial ischaemia. A 50-year-old woman who had been resuscitated from cardiac arrest transferred to our institution for evaluation and management of out-of-hospital cardiac arrest. We confirmed the diagnosis of significant myocardial bridging with evident myocardial ischaemia by coronary angiography, resting echocardiography and heart MRI. Vasospasm was thought to be a trigger factor judging from the transient ST elevation on electrocardiography. In addition, the finding of septal buckling was detected for the first time throughout the whole cardiac cycle by resting echocardiography in MB.

Conclusion

We report a rare case of survival after out-of-hospital cardiac arrest that might be caused by significant myocardial bridging-induced myocardial ischaemia, which was objectively confirmed by echocardiography and heart MRI. Although myocardial bridging is often overlooked as an aetiology for sudden cardiac death, this case highlights the importance of expanding the differential diagnosis to myocardial bridging in the work-up for the cause of sudden cardiac death.