A teenage boy with acute myocarditis and reversible microvascular angina: A case report.

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.

Case Report: Acute Eosinophilic Myocarditis With a Low-Flow Heart Failure With Preserved Ejection Fraction Phenotype.

Eosinophilic myocarditis is a rare subtype of myocarditis characterized by myocardial eosinophilic infiltration, and it is potentially fatal if left untreated. Although endomyocardial biopsy (EMB) is a cornerstone for the histological diagnosis of acute eosinophilic myocarditis (AEM), as it is an invasive procedure and has a low diagnostic accuracy, the diagnosis of AEM with hemodynamic instability remains challenging. We describe a case of AEM presenting as low-flow heart failure with preserved ejection fraction (HFpEF), with rapid progression to cardiogenic shock. The constellation of peripheral eosinophilia, increased left ventricular wall thickness, and HFpEF raised the suspicion of AEM. Contrast-enhanced computed tomography (CT) scan revealed heterogeneous hypoenhancement localized in the basal-to-mid septal and mid anterolateral walls of the left ventricle, strongly suggestive of acute inflammation. Based upon these findings, we performed CT-guided EMB, which lead to a definitive diagnosis. Subsequent high-dose corticosteroids allowed a rapid and dramatic recovery and normalization of cardiac structure and function. This case highlights the clinical importance of assessing AEM as a rare cause of HFpEF and the usefulness of CT-guided EMB in patients with hemodynamic instability.