A 17-year-old male was diagnosed with acute myocarditis based on the presence of CD3-positive T-lymphocytes in myocardial biopsy, normal coronary angiography, and focal increase in late gadolinium enhancement, T2 intensity and native T1 value. On day 2, the patient suffered from recurrence of chest pain with new ST segment elevations on electrocardiogram. A transient metabolic alteration (inversed lactate level of the coronary sinus relative to that of the coronary artery) accompanied by chest pain and electrocardiographic changes without epicardial coronary spasm in acetylcholine provocation test led to the diagnosis of microvascular angina, which is characterized by a transient myocardial ischemia secondary to a dysfunction of the resistance coronary vessels (<500 μm) that, because of their small size, are not visualized at coronary angiography. Benidipine, a dihydropyridine calcium channel antagonist, was started for chest pain due to microvascular angina. On 6 months after admission, when the findings of cardiac magnetic resonance were recovered, intracoronary infusion of acetylcholine did not induce chest pain, electrocardiographic changes, epicardial coronary spasm, and adverse changes of lactate levels of the coronary artery and sinus. The patient had no chest symptoms 2 years after discontinuation of benidipine.
Learning objective: The present case of microvascular angina, which was complicated with acute myocarditis on acute phase and recovered in chronic phase, indicates an association of myocardial inflammation with reversible coronary microvascular dysfunction.
Keywords: Acetylcholine provocation test; Case report; Inflammation; Microvascular angina; Microvascular function; Myocarditis.
© 2023 Japanese College of Cardiology. Published by Elsevier Ltd.