Cardiac time intervals predict major adverse cardiovascular events in individuals with type 1 diabetes without known heart disease

Background Cardiac time intervals, and in particular the myocardial performance index (MPI) which combines systolic and diastolic function, are associated with cardiovascular prognosis in various populations. We aimed to investigate if cardiac time intervals offer prognostic information on cardiovascular risk in individuals with type 1 diabetes (T1DM). Methods We prospectively included 1,088 individuals with T1DM without known heart disease (mean age 50±15 years; 53% male; duration of diabetes 26±15 years; 30% had albuminuria). All enrolled individuals underwent an echocardiographic examination with assessment of cardiac time intervals by color Tissue Doppler imaging M-mode. We evaluated the isovolumetric relaxation and contraction time (IVRT; IVCT) and ejection time (ET). The MPI was calculated as [(IVRT+IVCT)/ET]. In Cox proportional hazards models, we assessed major adverse cardiovascular events (MACE), a composite of incident heart failure or hospitalization for acute coronary syndrome or PCI/CABG. Multivariable models were adjusted for clinical information, pharmacotherapy and echocardiographic parameters. Results During the median follow-up time of 6 years [IQR 6, 7 years], 106 (10%) experienced MACE. In adjusted survival analyses the IVRT (HR: 1.13 per 10ms increase [1.01 to 1.26], P=0.026) and MPI (HR: 1.03 per 1 unit increase [1.01 to 1.04], P=0.005) were associated with MACE. Overall, the association between IVCT and outcome was borderline significant (HR: 1.15 per 10ms increase [0.97 to 1.36], P=0.10) while there was no association for ET (HR: 0.97 per 10ms increase [0.89 to 1.05], P=0.43). Sex modified the association for IVCT (P interaction<0.05) such that IVCT (HR: 1.23 per 10ms increase [1.02 to 1.49], P=0.027) and MPI (HR 1.03 per 1 unit increase [1.01 to 1.05], P=0.005; Figure) were associated with MACE in women but not in men. Conclusion Cardiac time intervals are positively associated with MACE in T1D without known heart disease. Furthermore, the association is modified by sex in that the IVCT and MPI provide independent and prognostic information on the risk of future cardiovascular events particularly in female individuals while not significant in men. These findings suggest sex differences in myocardial impairment related to T1D. Association between MACE and MPI in DM1 Funding Acknowledgement Type of funding source: None

1234 The cardiac isovolumetric contraction time is an independent predictor of cardiovascular morbidity in the general population

Background Color Tissue Doppler imaging (TDI) M-mode through the mitral leaflet is an easy and precise method to obtain the cardiac time intervals including the isovolumic contraction time (IVCT), the isovolumic relaxation time (IVRT) and the left ventricular ejection time (ET). The myocardial performance index (MPI) is defined as [(IVCT + IVRT)/ET]). It is our hypothesis that the duration of the cardiac time intervals can reveal early cardiac dysfunction. Purpose Our aim was to investigate if the cardiac time intervals can be used to predict cardiovascular morbidity in the general population. Methods A total of 1,915 participants from the general population (mean age 58 ± 16 years, 42% male) underwent a general health examination including TDI echocardiography. The IVCT, IVRT and ET were measured. The primary endpoint was the composite of ischemic heart disease (IHD), heart failure (HF) and atrial fibrillation (AF). Participants with previous IHD, prevalent HF and AF were excluded (n = 336). Results During a median follow-up time of 11 years, 277 (17.5%) participants reached the composite endpoint. Assessing the association between IVCT and the composite outcome, the risk of IHD, HF and AF increased with 20% per 10ms increase in IVCT (per 10 ms increase: HR 1.20; 95% CI (1.11-1.30), p < 0.001; figure). The association remained significant even after multivariable adjustment for clinical and echocardiographic parameters (per 10ms increase: HR 1.11; 95% CI (1.01-1.22), p = 0.037). IVRT, LVET and MPI were significant predictors of the composite outcome in unadjusted analysis (p < 0.001 for all). However, none remained significant after multivariable adjustment. Additionally, the IVCT provided incremental prognostic information, as assessed by a significant increase in the net reclassification improvement (NRI) index, beyond the SCORE risk chart (continuous NRI, 0.266; 95% CI, 0.093-0.386) and the ACC/AHA Pooled Cohort Equation (continuous NRI, 0.252; 95% CI, 0.078-0.371). Conclusion In a low risk general population, the IVCT provides novel and independent prognostic information on the long-term risk of cardiovascular morbidity. Abstract 1234 Figure.