In this study, we evaluated patients with pulmonary arterial hypertension (PAH) and impaired right ventricular function. We used cardiac MRI for the detection of myocardial delayed enhancement (MDE) and its possible association with other clinical variables. 20 patients (6 males and 14 females, aged 44.5+/-11 years; 15 New York Heart Association class III, 5 class IV) with known PAH (13 idiopathic, 7 resulting from chronic pulmonary embolism) were evaluated for the detection of MDE. Short-axis cine images of the heart were made for ventricular function assessment using a steady-state free precession sequence. For MDE evaluation, a short-axis phase-sensitive inversion recovery sequence was performed 10 min after intravenous administration of 0.2 mmol kg(-1) gadodiamide. Right ventricle (RV) systolic dysfunction, RV enlargement and RV hypertrophy were present in 20 patients (RV ejection fraction, 21.5+/-7.2%; RV diastolic diameter, 5.97+/-0.79 cm; RV wall thickness, 0.73+/-0.10 cm). 13 of the 20 patients (65%) were positive for MDE (10 anterior, 12 inferior). All 13 positive patients with MDE demonstrated small hyperintense areas at the insertion points of the RV free wall in the interventricular septum. We found no significant correlation between MDE and ejection fraction or other haemodynamic variables. In this study, MDE correlated positively only with the duration of disease. We found that septal MDE can be present in patients with PAH and impaired ventricular function. However, further studies are necessary to investigate this possible association and its prognostic implication.