Excitation-Contraction Coupling Time is More Sensitive in Evaluating Cardiac Systolic Function

Abstract

Background:Pressure overload-induced myocardial hypertrophy is a key step leading to heart failure. Previous cellular and animal studies demonstrated that deteriorated excitation–contraction coupling occurs as early as the compensated stage of hypertrophy before the global decrease in left ventricular ejection fraction (LVEF). This study was to evaluate the cardiac electromechanical coupling time in evaluating cardiac systolic function in the early stage of heart failure.Methods:Twenty-six patients with Stage B heart failure (SBHF) and 31 healthy controls (CONs) were enrolled in this study. M-mode echocardiography was performed to measure LVEF. Tissue Doppler imaging (TDI) combined with electrocardiography (ECG) was used to measure cardiac electromechanical coupling time.Results:There was no significant difference in LVEF between SBHF patients and CONs (64.23 ± 8.91% vs. 64.52 ± 5.90%; P = 0.886). However, all four electromechanical coupling time courses (Qsb: onset of Q wave on ECG to beginning of S wave on TDI, Qst: onset of Q wave on ECG to top of S wave on TDI, Rsb: top of R wave on ECG to beginning of S wave on TDI, and Rst: top of R wave on ECG to top of S wave on TDI) of SBHF patients were significantly longer than those of CONs (Qsb: 119.19 ± 35.68 ms vs. 80.30 ± 14.81 ms, P < 0.001; Qst: 165.42 ± 60.93 ms vs. 129.04 ± 16.97 ms, P = 0.006; Rsb: 82.43 ± 33.66 ms vs. 48.30 ± 15.18 ms, P < 0.001; and Rst: 122.37 ± 36.66 ms vs. 93.25 ± 16.72 ms, P = 0.001), and the Qsb, Rsb, and Rst time showed a significantly higher sensitivity than LVEF (Rst: P =0.032; Rsb: P = 0.003; and Qsb: P = 0.004).Conclusions:The cardiac electromechanical coupling time is more sensitive than LVEF in evaluating cardiac systolic function.

Model Embraced Electromechanical Coupling Time for Estimation of Heart Failure in Patients With Hypertrophic Cardiomyopathy

“…HR is related to the electrical and mechanical activities of the heart ( 18 ). We determined all the data of electromechanical coupling time courses with HR correction, referenced as the formula in a previous study: electromechanical coupling time courses with HR correction = electromechanical coupling time courses without HR correction/HR × 60 ( 12 , 18 ).…”

“…Cardiac excitation-contraction coupling is a process that links cardiomyocyte action potential to cardiomyocyte contractile ( 11 ). The process is difficult to test experimentally; nevertheless, cardiac electromechanical coupling efficiency, presented as electromechanical coupling time, previously evaluated by combining tissue Doppler imaging (TDI) echo and electrocardiogram (ECG) measurement has been proven ( 12 ). In a preliminary study, electromechanical coupling time was proposed as a potential index for evaluating cardiac systolic function in patients with stage B HF, which is a precursor of HF ( 12 , 13 ).…”

“…The process is difficult to test experimentally; nevertheless, cardiac electromechanical coupling efficiency, presented as electromechanical coupling time, previously evaluated by combining tissue Doppler imaging (TDI) echo and electrocardiogram (ECG) measurement has been proven ( 12 ). In a preliminary study, electromechanical coupling time was proposed as a potential index for evaluating cardiac systolic function in patients with stage B HF, which is a precursor of HF ( 12 , 13 ). Few studies have explored electromechanical coupling time and outcomes in HCM, and we hypothesised that electromechanical coupling time was delayed in HCM with HF and would predict HF in patients with HCM.…”

Data_Sheet_1.DOCX

“…ECG was performed using a Vevo 2,100 system (FUJIFILM VisualSonics, Canada), and the cardiac dimensions and functional parameters were measured. The tissue Doppler imaging (TDI) echo combined with ECG was used to measure the electromechanical coupling time at the lateral wall of the left ventricle as described previously (19).…”