Impact of Functional Mitral Regurgitation on Left Ventricular Strain in Nonischemic Dilated Cardiomyopathy Patients with Type 2 Mellitus Diabetes: A Magnetic Resonance Feature Tracking Study

Background: The impact of functional mitral regurgitation and type 2 mellitus diabetes (T2DM) on left ventricular (LV) strain in nonischemic dilated cardiomyopathy (NIDCM) patients remains unclear. Purpose: To evaluate the impact of mitral regurgitation severity on LV strain, and explore additive effect of T2DM on LV function across varying mitral regurgitation severity levels in NIDCM patients. Study TypeRetrospective. Population: 352 NIDCM (T2DM-) patients (49.1 +/- 14.6 years, 67% male) (207, 85, and 60 no/mild, moderate, and severe mitral regurgitation) and 96 NIDCM (T2DM+) patients (55.2 +/- 12.4 years, 77% male) (47, 30, and 19 no/mild, moderate, and severe mitral regurgitation). Field Strength/Sequence: 3.0 T/balanced steady-state free precession sequence. Assessment: LV geometric parameters and strain were measured and compared among groups. Determinants of LV strain were investigated. Statistical Test: Student's t-test, Mann-Whitney U test, one-way ANOVA, Kruskal-Wallis test, univariable and multivariable linear regression. P < 0.05 was considered statistically significant. Results: LV GLPS and longitudinal PDSR decreased gradually with increasing mitral regurgitation severity in NIDCM patients with T2DM(GLPS: -5.7% +/- 2.1% vs. -4.3% +/- 1.6% vs. -2.6% +/- 1.3%; longitudinal PDSR:0.5 +/- 0.2 sec-1 vs. 0.4 +/- 0.2 sec-1 vs. 0.3 +/- 0.1 sec-1). NIDCM (T2DM+) demonstrated decreased GCPS and GLPS in the no/mild subgroup, reduced LV GCPS, GLPS, and longitudinal PDSR in the moderate subgroup, and reduced GRPS, GCPS, GLPS, and longitudinal PDSR in the severe subgroup compared with NIDCM (T2DM-) patients. Multivariable regression analysis identified that mitral regurgitation severity (beta = -0.13, 0.15, and 0.25 for GRPS, GCPS, and GLPS) and the presence of T2DM (beta = 0.14 and 0.13 for GCPS and GLPS) were independent determinants of LV strains in NIDCM patients. Data Conclusion: Increased mitral regurgitation severity is associated with reduced LV strains in NIDCM patients with T2DM. The presence of T2DM exacerbated the decline of LV function across various mitral regurgitation levels in NIDCM patients, resulting in reduced LV strains.