Dilated phenotype of hypertrophic cardiomyopathy: cardiac magnetic resonance assessment and 9-year follow-up

Although most patients with hypertrophic cardiomyopathy (HCM) have a good prognosis (1), approximately 7% rapidly progress to severe systolic dysfunction (2), which is known as the dilated phase, end-stage, or decompensated HCM (DHCM) (3).Patients with DHCM usually have a poor prognosis and are difficult to identify at an early stage.The dynamic evolution of cardiac abnormalities in patients with DHCM has rarely been reported.Herein, we describe the case of a 48-year-old man who progressed to DHCM and underwent three cardiac magnetic resonance (CMR) scans in 2010, 2014, and 2017.The patient, with a 4-year history of HCM, presented to our center in 2010 with shortness of breath after heavy activity.The patient had no family history of malignant tumors, heart disease, diabetes, hypertension, hereditary disease, and contagious disease.Electrocardiography revealed T-wave changes, a first-degree atrioventricular block, and occasional atrial and ventricular premature beats.Echocardiography showed left atrial (LA) enlargement, a thickened left ventricular (LV) wall, and varying degrees of septal thickening.Blood tests revealed elevated N-terminal pro-brain natriuretic peptide (NT-proBNP; 2,042.6 pg/mL; normal values, 0-250 pg/mL) and cardiac troponin I (cTnI; 1.244 ng/mL; normal values, 0-0.04 ng/mL).Coronary computed tomography angiography (CCTA) showed no abnormalities during follow-up.The first CMR scan showed a mildly dilated LA chamber, a small LV chamber, and a significantly asymmetrically thickened LV wall, especially the interventricular septum (Figure 1, A1, B1).