Association between cardiac time intervals and incident heart failure after acute coronary syndrome

Abstract

Abstract Background Cardiac time intervals are sensitive markers of myocardial dysfunction that predisposes to heart failure (HF). Color tissue Doppler imaging (TDI) curved M-mode is a reliable method for measuring cardiac time intervals. Purpose We aimed to investigate the association between cardiac time intervals and HF in patients with acute coronary syndrome (ACS). Methods This was a retrospective cohort study of 580 ACS patients treated with percutaneous coronary intervention (PCI). Patients underwent an echocardiography examination performed a median of two days after PCI. By echocardiography cardiac time intervals including isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT), and ejection time (ET) were obtained by TDI curved M-mode and used to derive the myocardial performance index (MPI). The outcome was incident HF. Patients with prevalent at baseline HF were excluded from the analysis. Results The final study sample consisted of 387 patients, 73% were male, the mean age was 64 years, 76% of the ACS events were STEMI and LVEF and GLS were 42% and -13.1%, respectively. During follow-up (median 4.3, IQR:1.0-6.7 years), 140 (36%) developed HF. In unadjusted analyses, longer combined indexes were associated with a higher risk of HF (IVRT/ET: HR 1.24 (1.07-1.43), P = 0.003, per 0.1 increase) and (IVCT/ET: HR 1.44 (1.10-1.91), P = 0.010, per 0.1 increase), and so was higher MPI (HR 1.20 (1.08-1.34),P = 0.001, per 0.1 increase). In addition, shorter ET was also associated with higher HF risk (HR 1.13 (1.07-1.18), P<0.001 per 10ms decrease). MPI and IVCT/ET showed a curvilinear association with the outcome, whereas a linear association was observed for ET and IVRT/ET to the outcome (figure 1). After multivariable adjustment for cardiovascular risk factors, only MPI (HR 1.13 (1.01-1.27), P = 0.034), ET (HR 1.09 (1.01-1.17), P = 0.025), and IVCT/ET (HR1.37 (1.04-1.81), P = 0.023) remained significantly associated with HF. Of note, left ventricular ejection fraction (LVEF) significantly modified the association between ET and HF (p for interaction = 0.002), such that ET was associated with HF even in those with preserved LVEF (>40%) (HR 1.13 (1.02-1.24, P = 0.017, per 10ms decrease), but not in those with reduced LVEF (HR 1.02 (0.96-1.08), P = 0.56, per 10ms decrease). These findings also persisted after adjustment for cardiovascular risk factors. Conclusion Shortened ET, prolongation of combined indexes, and higher MPI were associated with an increased risk of incident HF. In addition, shortening of the ET was associated with an increased risk of HF in patients with preserved systolic function by LVEF.