JACC Case Rep. 2026 Jul 22:109425. doi: 10.1016/j.jaccas.2026.109425. Online ahead of print.
ABSTRACT
BACKGROUND: Myocardial bridging (MB) may cause myocardial ischemia through impaired diastolic coronary perfusion and coronary vasomotor dysfunction, occasionally presenting as exertional presyncope or syncope.
CASE SUMMARY: We report 2 patients with exertional presyncope/syncope caused by hemodynamically significant MB and concomitant epicardial coronary spasm. Coronary angiography showed no obstructive disease. Acetylcholine provocation induced diffuse spasm in the mid- to distal left anterior descending artery, whereas intracoronary nitroglycerine unmasked systolic compression of a mid-left anterior descending artery MB. Dobutamine stress with resting full-cycle ratio demonstrated functionally significant ischemia and reproduced symptoms, accompanied by marked reductions in distal coronary and systemic blood pressure. Treatment with diltiazem resulted in complete symptom resolution.
DISCUSSION: MB may cause exertional syncope through stress-induced impairment of diastolic coronary perfusion, exacerbated by tachycardia and concomitant vasospasm.
TAKE-HOME MESSAGES: Comprehensive invasive vasomotor and physiological assessment is valuable for identifying clinically significant MB and concomitant coronary vasospasm in patients presenting with exertional presyncope or syncope.
PMID:42484566 | DOI:10.1016/j.jaccas.2026.109425