Unusual ST elevation at stress electrocardiography in a young athlete

Clinical History

A 19-year-old professional soccer player was found to have an unusual ST elevation in the recovery phase of stress-test ECG during a routine medical screening. He had no history of pain or any other ischaemic symptoms.

Imaging Findings

Cardiac transthoracic colour-Doppler US imaging did not detect any alteration in heart structure or function.
128-row MDCT coronary angiography performed with prospective ECG-gating and a reduced radiation dose technique (100kV tube voltage and iterative image reconstruction; total effective dose 1.78mSv) showed intramyocardial course of the first diagonal (D1) and the first obtuse marginal (OM1) branches (Fig. 1, 2) with reduced vessel calibre in the tunneled segments (Fig. 3). CT-based semiquantitative evaluation of myocardial perfusion also showed a small area of reduced perfusion in the myocardial territory distal to those branches (Fig. 4).

Discussion

Myocardial bridging (MB) is the most common congenital anomaly of coronary arteries. Myocardium overlying a segment of coronary artery (called “tunneled artery”) causes myocardial bridging. This condition is usually asymptomatic but sometimes can lead to angina pectoris, myocardial infarction, and life-threatening arrhythmia with potential sudden death. In fact, during systole, myocardium compresses the vessel and ischaemia can occur. Pathophysiological mechanisms underlying MB-induced myocardial ischaemia includes vasospasm and systolic kinking of the artery, increased contractility, high heart rate, shortened diastolic perfusion time, compression of an artery, and increased blood flow velocity. Ischaemia may also depend on the intramyocardial depth of the tunneled segment [1].
Stress-test electrocardiography can show ischaemic alterations of the ST segment. Traditionally, conventional coronary angiography is the mainstay for diagnosis and shows focal systolic compression of the artery that almost completely recedes in diastole. In uncertain cases, systolic narrowing at the myocardial bridge can be accentuated by intracoronary injection of nitroglycerin.
Coronary CT angiography (CTCA) is a noninvasive technique that allows direct assessment of the diameter, course, and walls of the coronary arteries. Therefore, CTCA offers a unique opportunity to evaluate the real incidence, location, and morphology of MB in an in-vivo setting.
The main therapy for MB cases with signs of ischaemia is medical treatment, which essentially relies on the administration of beta-blockers and calcium antagonists. Further therapeutic options for MB cases refractory to medical treatment are coronary stenting, surgical myocardial revascularisation with placement of bypass grafts, and myotomy [2].

Differential Diagnosis List

Final Diagnosis

Myocardial bridge

URL:	https://www.eurorad.org/case/10459
DOI:	10.1594/EURORAD/CASE.10459
ISSN:	1563-4086