TITLE:
Effect of cardiac ventricular mechanical contraction on the characteristics of the ECG: A simulation study
AUTHORS:
Ismail Adeniran, Jules C. Hancox, Henggui Zhang
KEYWORDS:
Ventricles; Mechanical Contraction;Electrophysiology; Simulation; ECG
JOURNAL NAME:
Journal of Biomedical Science and Engineering,
Vol.6 No.12A,
December
27,
2013
ABSTRACT:
Introduction:
The 12-lead electrocardiogram (ECG) is the most widely-used tool for the
detection and diagnosis of cardiac conditions including myocardial infarction
and ischemia. It has therefore been a focus of cardiac modeling. However, the most
contemporary in silico ECG
investigations of the intact heart have assumed a static heart and ignored the
mechanical contraction that is an essential component of cardiac function. The
aim of this study was to utilize electromechanically coupled human ventricle
models to explore the consequences of ventricular mechanical contraction on the
ECG profiles. Methods and Results: Biophysically detailed human ventricular
cell models incorporating contractile
activity and a stretchactivated current (Isac) were incorporated into a 3D human ventricular
model within a human torso, from which 12-lead ECGs were computed at a stimulation
rate of 1 Hz. Compared to the static model, ventricular contraction without Isac had little effect on the
QRS complex, but shifted the T-wave peak leftwards and reduced its peak amplitude.
With Isac, ventricular
mechanical contraction increased the QRS duration by 23% and QT interval by 5%.
Conclusion: Mechanical contraction of the heart has a significant effect on the
morphology and characteristics of the ECG particularly on the T-wave. The alteration
of the cell membrane kinetics by stretch via Isac further exacerbates these effects. Our simulation
data suggest that mechanical contraction should be considered in the
interpretation of ECGs in pathological conditions, especially those in which
mechanical contraction of the heart is impaired.