Relation of Replacement Fibrosis to Left Ventricular Diastolic Function in Patients with Dilated Cardiomyopathy

Abstract

Previous studies have shown that delayed hyperenhancement (HE) by cardiac magnetic resonance (CMR) is related to left ventricular (LV) stiffness in a variety of cardiac diseases. However, it is not known whether this relation is also present in dilated cardiomyopathy (DCM), in which replacement fibrosis is less extensive. Consecutive patients with DCM (n= 50, age 56 ± 13 years, 20 females) were studied with CMR and two-dimensional and Doppler echocardiography. CMR images with breath-hold segmented inversion-recovery sequence were acquired 10 minutes after an intravenous bolus of gadolinium. The scar tissue distribution and extent were calculated in the 17 LV segments. LV diastolic function was assessed using mitral inflow and tissue Doppler velocities at the septal and lateral sides of the mitral annulus. The group had an ejection fraction of 30% ± 11% and left atrial volume of 103 ± 50 mL by CMR. HE was present in 31 patients with a mean scar burden of 4% ± 7.6%. Patients with DCM without HE had a significantly higher septal E/e' ratio than patients with scar (P= .05), and there was no significant correlation between deceleration time and extent of HE. Lateral late diastolic velocity (a') had a weak inverse relation with the number of segments with HE (r= -0.44, P= .005) and with scar burden (r= -0.31, P= .05). Patients with DCM without HE have higher LV filling pressures than patients with HE. Our findings suggest that other factors influence LV stiffness to a larger extent than replacement fibrosis in this population.