In human cardiac muscle, the CV consists of two components, the longitudinal (between 60 and 70 cm/s ) and the transversal (TCV, around 50 cm/s ). The reduction of CV was shown to increase the risk of reentrant activities that can lead to cardiac arrhythmias (for review, see King et al. In comparison with normal hearts, the myocardial CV was found to be significantly reduced in diseased animal and human hearts. ![]() IntroductionĬardiac conduction velocity (CV), the speed with which an electrical impulse propagates through the cardiac tissue, is one of the most important electrophysiological characteristics of heart muscle. Although the changes induced by the clinically relevant reduction of TCV are not critical for a healthy heart, they may represent an important factor limiting the heart function under disease conditions. In conclusion, these results suggest that the pumping efficacy of the human LV decreases with lower TCV due to a higher energy consumption and lower LV power. These negative effects increase progressively with further reduction of TCV. The simulations have shown that a 50% decrease in TCV prolongs substantially the isovolumic contraction, decelerates slightly the LV pressure rise, increases the LV energy consumption, and reduces the LV power. ![]() The model outputs are further exploited in the lumped “Windkessel” model of the human cardiovascular system (based on electrohydrodynamic analogy of respective differential equations) to simulate the impact of changes of and IVCD on chosen systemic parameters (ejection fraction, LV power, cardiac output, and blood pressure). ![]() The applied three-dimensional finite element model of isovolumic contraction of the human LV incorporates transmural gradients in electromechanical delay and myocyte shortening velocity and evaluates the impact of TCV reduction on pressure rise (namely, ) and on isovolumic contraction duration (IVCD) in a healthy LV. However, it is unclear whether the clinically observed decrease of TCV contributes significantly to a reduction of LV contractility. In a healthy heart, the TCV contributes to synchronization of the onset of contraction in individual layers of the left ventricle (LV). This study investigates the impact of reduced transmural conduction velocity (TCV) on output parameters of the human heart.
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