Right ventricular phenotypic characteristics in subjects with primary pulmonary hypertension or idiopathic dilated cardiomyopathy.

BACKGROUND: Studies of animal models and human subjects with cardiomyopathies suggest that cardiac myocyte and ventricular chamber remodeling show distinct phenotypic characteristics that may be dependent on specific signaling pathways. METHODS AND
RESULTS: In this study, we characterize right ventricular (RV) chamber size, end-diastolic thickness, myocardial mass, and ejection fraction (EF) in human subjects with chronic heart failure from primary pulmonary hypertension (PPH; n = 10) and idiopathic dilated cardiomyopathy (IDC; n = 10). Subjects underwent gated cardiac magnetic resonance imaging (MRI), and the RVs were phenotypically classified based on the presence or absence of hypertrophy (increased mass), systolic dysfunction (reduced EF), and degree of wall thickness (concentric v eccentric pattern of hypertrophy). Within this schema, five abnormal phenotypes could be identified. In PPH subjects, in whom the RV is subjected to the uniform insult of chronic pressure overload, four different abnormal phenotypes were identified.
CONCLUSIONS: These data indicate that distinct structural/functional ventricular chamber phenotypes may be classified by MRI, and that a uniform insult can result in multiple RV phenotypes.