['To assess the degree of myocardial fibrosis in patients with primary aldosteronism (PA).', 'Twenty-five patients with PA and 12 age-matched healthy volunteers underwent cine and late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) on a 1.5 T MR system. From volume-time curves of cine MRI, the time for deceleration (Tdec) was determined to assess the left ventricle (LV) chamber stiffness. Based on phase-sensitive reconstructed LGE images, a fibrosis index called enhancement value (EV) was computed as the signal intensity change in the myocardium over blood before and after contrast. Both Tdec and EV were compared between patients and controls. The association between Tdec and EV was investigated.', 'Patients showed a significantly higher EV (0.43 ± 0.05 vs. 0.36 ± 0.07; P = 0.002) and a significantly shorter Tdec (11.5 ± 3.5 %RR vs. 15.3 ± 2.4 %RR; P = 0.004) than controls. Significant correlations between EV and Tdec were observed in patients (r = -0.46, P = 0.018), in controls (r = -0.68, P = 0.015) and in all subjects (r = -0.63, P < 0.001).'] Is contrast-enhanced MRI index of diffuse myocardial fibrosis increased in primary aldosteronism?