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

Background: Cardiac time intervals are sensitive markers of myocardial dysfunction that predispose to heart failure (HF). We aimed to investigate the association between cardiac time intervals and HF in patients with acute coronary syndrome (ACS).

Methods: This study included 386 ACS patients treated with percutaneous coronary intervention (PCI). Patients underwent an echocardiography examination a median of two days after PCI. Cardiac time intervals including isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT), and systolic ejection time (ET), and myocardial performance index (MPI) were obtained by tissue Doppler echocardiography. The outcome was incident HF.

Results: During follow-up (median 4.3, IQR:1.0-6.7 years), 140 (36%) developed HF. In unadjusted analyses, IVRT was not associated with HF (HR 1.02 (0.95-1.10), p = 0.61, per 10ms increase), and neither was IVCT (HR 0.07 (0.95-1.22), p = 0.26, per 10ms increase). Increasing MPI was associated with a higher risk of HF (HR 1.20 (1.08-1.34), P = 0.001, per 0.1 increase), and so was decreasing ET (HR 1.13 (1.07-1.18), P < 0.001 per 10ms decrease). After multivariable adjustment for cardiovascular risk factors, MPI (HR 1.13 (1.01-1.27), P = 0.034) and ET (HR 1.09 (1.01-1.17), P = 0.025) remained significantly associated with incident HF. LVEF modified the association between ET and HF (p for interaction = 0.002), such that ET was associated with HF in patients with LVEF ≥ 36% (HR = 1.15 (1.06-1.24), P = 0.001, per 10ms decrease).

Conclusion: In patients admitted with ACS, shortened ET and higher MPI were independently associated with an increased risk of incident HF. Additionally, ET was associated with incident HF in patients with LVEF above 36%.