Key result
Numerical model links mitral stenosis to arrhythmia-stimulating stretch and regurgitation to more ectopic beats.
Why the study?
Left ventricular valve disorders contribute significantly to heart disease, and there was a need to investigate how mitral and aortic valve stenoses and regurgitation affect mechano-electric feedback and arrhythmia generation using a model that incorporates cardiac feedback mechanisms.
Computational modeling suggests that arrhythmia resulting from mechano-electric feedback disorders is more severe in the presence of valve regurgitation.
Answers are grounded in this paper and cite their sources.
May warrant arrhythmia vigilance in valvular disease; leaves open human translation of numerical mechano-electric feedback models.
Cardiac diseases and failure make up one of largest contributions to global mortality and significantly detriment the quality of life for millions of others. Disorders in the valves of the left ventricle are a prominent example of heart disease, with prolapse, regurgitation, and stenoses-the three main valve disorders. It is widely known that mitral valve prolapse increases the susceptibility to cardiac arrhythmia. Here, we investigate stenoses and regurgitation of the mitral and aortic valves in the left ventricle using a synergistic low-order numerical model. The model synergy derives from the incorporation of the mechanical, chemical, and electrical elements. As an alternative framework to the time-varying elastance (TVE) method, it allows feedback mechanisms at work in the heart to be considered. The TVE model imposes the ventricular pressure-volume relationship using a periodic function rather than calculating it consistently. Using our synergistic approach, the effects of valve disorders on the mechano-electric-feedback (MEF) are investigated. The MEF is the influence of cellular mechanics on the electrical activity, and significantly contributes to the generation of arrhythmia. We further investigate stenoses and regurgitation of the mitral and aortic valves and their relationship with the MEF and generation of arrhythmia. Mitral valve stenosis is found to increase the sensitivity to arrhythmia-stimulating systolic stretch, and reduces the sensitivity to diastolic stretch. Aortic valve stenosis does not change the sensitivity to arrhythmia-stimulating stretch, and regurgitation reduces it. A key result is found when valve regurgitation is accompanied by diastolic stretch. In the presence of MEF disorder, ectopic beats become far more frequent when accompanied by valve regurgitation. Therefore, arrhythmia resulting from a disorder in the MEF will be more severe when valve regurgitation is present.
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Pearce et al. (2022) studied Left ventricular valve disorders and arrhythmia. Synergistic lumped parameter cardiovascular numerical model vs. Time-varying elastance (TVE) method was evaluated on Sensitivity to arrhythmia-stimulating stretch and frequency of ectopic beats. Using a synergistic numerical model, mitral valve stenosis increased sensitivity to arrhythmia-stimulating systolic stretch, and valve regurgitation with MEF disorder increased ectopic beats.
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