Abstract
BACKGROUND: Hypertrophic cardiomyopathy with extreme hypertrophy, biventricular obstruction and diffuse myocardial fibrosis complicated by myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) is a rare phenotype. Evidence and guideline recommendations are still lacking for a treatment strategy. CASE PRESENTATION: Emergency coronary angiography was performed in a 38-year-old man with a 2-year history of nonobstructive hypertrophic cardiomyopathy (HCM) presenting with acute myocardial infarction. The coronary angiogram yielded no stenotic lesions but showed a diffusely dilated left descending artery with slow blood flow. All evidence from biomarker analysis, electrocardiography, echocardiography, and imaging supported the diagnosis of acute myocardial infarction in the left ventricular anterior wall. The echocardiogram demonstrated severe interventricular and apical hypertrophy, severe left ventricular outflow tract obstruction and mild right ventricular outflow tract obstruction. Cardiac magnetic resonance imaging showed a concentric morphological subtype of HCM with diffuse late gadolinium enhancement in the left ventricle. Extended septal myectomy was performed 1 month later, and the patient recovered well. CONCLUSIONS: Hypertrophic obstructive cardiomyopathy with acute myocardial infarction is an indication for coronary angiography. Septal reduction surgery could be performed cautiously in HCM patients with extreme hypertrophy, biventricular obstruction and diffuse myocardial fibrosis complicated by MINOCA to improve the patient's symptoms.