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

Area of Science:

• Cardiology
• Physiology

Background:

• Pressure overload leads to myocardial hypertrophy, a precursor to heart failure.
• Deteriorated excitation-contraction coupling is an early sign of compensated hypertrophy, preceding reduced left ventricular ejection fraction (LVEF).

Purpose of the Study:

• To evaluate cardiac electromechanical coupling time for assessing cardiac systolic function in early-stage heart failure.

Main Methods:

• Compared 26 Stage B heart failure patients (SBHF) with 31 healthy controls (CONs).
• Measured LVEF using M-mode echocardiography.
• Assessed cardiac electromechanical coupling time using Tissue Doppler imaging (TDI) and electrocardiography (ECG).

Main Results:

• No significant difference in LVEF between SBHF patients and controls.
• All four measured electromechanical coupling time courses (Qsb, Qst, Rsb, Rst) were significantly longer in SBHF patients.
• Qsb, Rsb, and Rst times demonstrated significantly higher sensitivity than LVEF in detecting early systolic dysfunction.

Conclusions:

• Cardiac electromechanical coupling time is a more sensitive indicator of cardiac systolic function than LVEF in early heart failure stages.