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

Abstract

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.

Keywords: Cardiac arrest; Myocardial bridging; Myocardial ischaemia.

Fig. 1

The electrocardiogram (ECG) performed in the local emergency department showed a normal sinus rhythm with a right bundle branch block (RBBB) with ST elevation and Q-waves over V1–V4 (a). ECG performed at our institution showed complete resolution of ST elevation on V1–V4 (b). Coronary angiography showed significant myocardial bridging in the distal segment of the left anterior descending coronary artery and diagonal branch with compression up to 100% stenosis during systole (arrow) (c, d)

Fig. 2

3D volume rendered reconstruction of the heart and coronary arteries showed high take off of the right coronary artery (a) and distal segment of the left anterior descending coronary artery and diagonal branch with a superficial intra-myocardial course (arrow) (b). Resting echocardiography showed focal septal wall motion abnormalities called septal buckling (arrow) at end systole (c) and early diastole (d). T2-weighted heart MRI image showed myocardial wall thinning and subendocardial myocardial oedema (arrow) in the mid-ventricular to apical anterior and septal regions (e). Late gadolinium enhancement imaging showed a high signal intensity in the same region (f)