Cardiac fibrosis detected by magnetic resonance imaging on predicting time course diversity of left ventricular reverse remodeling in patients with idiopathic dilated cardiomyopathy
This study aimed to identify the association between the time course of left ventricular reverse remodeling (LVRR) and late gadolinium enhancement in cardiac magnetic resonance imaging (LGE-cMRI) in patients with idiopathic dilated cardiomyopathy (IDCM). We identified 214 IDCM patients treated by optimal pharmacotherapies. LVRR was defined as ≥10 % increment in LV ejection fraction along with ≥10 % reduction in LV end-diastolic dimension. Findings of LGE-cMRI focusing on presence and extent of LGE were evaluated at baseline. Echocardiographic evaluation for detecting LVRR was performed in all patients for 3 years. The primary endpoint was defined as composite events (CEs) including readmission for heart failure, detection of major ventricular arrhythmia, and all-cause mortality. LVRR was found at <1 year in 59 patients (28 %, early responder), ≥1 year in 56 patients (26 %, late responder), and was absent in 99 patients (46 %, non-responder). Multivariate Cox-proportional hazards analysis revealed that both early responders (P = 0.02) and late responders (P < 0.001) had lower incidence of CEs than non-responders. Among 66 subjects (23 %) with complete cMRI evaluation, LGE was detected more often in late and non- than early responders (65, 83 vs. 23 % P < 0.001, respectively), whereas the LGE area was smaller in both early and late than non-responders (2 ± 3, 4 ± 3 vs. 12 ± 10 %, P < 0.001, respectively). In conclusion, evaluating the presence and the extent of LGE is useful for predicting the clinical differences of LVRR time course and subsequent long-term outcomes.