Diffuse Late Gadolinium Enhancement by Cardiovascular Magnetic Resonance Predicts Significant Intraventricular Systolic Dyssynchrony in Patients With Non-Ischemic Dilated Cardiomyopathy

Background

Left ventricular dyssynchrony and myocardial fibrosis are common findings in patients with nonischemic dilated cardiomyopathy (NDCM). The aim of this study was to investigate the association between myocardial fibrosis and intraventricular systolic dyssynchrony (DYS-sys) in patients with NDCM.

Methods

Thirty-nine patients with NDCM and sinus rhythm were enrolled. Intraventricular DYS-sys was evaluated using Doppler tissue imaging, and cardiac fibrosis was assessed with cardiovascular magnetic resonance imaging with a 17-segment cardiac model. Each segment was graded on a 2-point scale (segmental fibrosis score): 0 = absence of late gadolinium enhancement, and 1 = presence of late gadolinium enhancement. A cardiac fibrosis index was calculated as 17/(17 − sum of fibrotic segments). Receiver operating characteristic analysis was performed to determine the utility of the cardiac fibrosis index to predict intraventricular systolic dyssynchrony.

Results

Patients with DYS-sys had larger left atrial size (P = .004) and left ventricular end-systolic (P = .028) and end-diastolic (P = .034) volumes and lower tricuspid annular Doppler tissue imaging peak systolic velocities (P = .037) compared with patients without DYS-sys. A cardiac fibrosis index ≥ 1.4 predicted significant DYS-sys with 92% sensitivity and 60% specificity (area under the receiver operating characteristic curve, 0.703; 95% confidence interval, 0.512-0.893; P = .035). Patients with cardiac fibrosis indexes ≥ 1.4 (group 1) had larger left ventricular end-systolic (P = .044) and end-diastolic (P = .034) volumes than those with cardiac fibrosis indexes < 1.4 (group 2). Nine of 11 patients (82%) in group 1 and 6 of 28 patients (21%) in group 2 had significant DYS-sys (Pearson's χ² = 12.169, P < .0001). Logistic regression analysis revealed that cardiac fibrosis index ≥ 1.4 (odds ratio, 11.2; 95% confidence interval, 1.72-71.4; P = .012) was an independent predictor of DYS-sys.

Conclusion

Patients with NDCM and prominent cardiac fibrosis have significant DYS-sys. The cardiac fibrosis index is a useful tool to predict DYS-sys.

Keywords: Cardiac fibrosis, Dyssynchrony, Dilated cardiomyopathy