Thakare Sanket, Mathew Joseph, Zlochiver Sharon, Zhao Xiaopeng, Tolkacheva Elena G
Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Department of Biomedical Engineering, Tel-Aviv University, Tel-Aviv 69379, Israel.
Chaos. 2020 Aug;30(8):083123. doi: 10.1063/5.0005432.
Cardiac alternans is a proarrhythmic state in which the action potential duration (APD) of cardiac myocytes alternate between long and short values and often occurs under conditions of rapid pacing of cardiac tissue. In the ventricles, alternans is especially dangerous due to the life-threatening risk of developing arrhythmias, such as ventricular fibrillation. Alternans can be formed in periodically paced tissue as a result of pacing itself. Recently, it has been demonstrated that this pacing-induced alternans can be prevented by performing constant diastolic interval (DI) pacing, in which DI is independent of APD. However, constant DI pacing is difficult to implement in experimental settings since it requires the real-time measurement of APD. A more practical way was proposed based on electrocardiograms (ECGs), which give an indirect measure of the global DI relaxation period through the TR interval assessment. Previously, we demonstrated that constant TR pacing prevented alternans formation in isolated Langendorff-perfused rabbit hearts. However, the efficacy of "local" constant DI pacing vs "global" constant TR pacing in preventing alternans formation has never been investigated. Thus, the purpose of this study was to implement an ECG-based constant TR pacing in a 1D numerical model of human ventricular tissue and to compare the dynamical behavior of cardiac tissue with that resulted from a constant DI pacing. The results showed that both constant TR and constant DI pacing prevented the onset of alternans until lower basic cycle length when compared to periodic pacing. For longer cable lengths, constant TR pacing was shown to exhibit greater control on alternans than constant DI pacing.
心脏交替脉是一种促心律失常状态，在此状态下心肌细胞的动作电位持续时间（APD）在长值和短值之间交替变化，且常发生于心脏组织快速起搏的情况下。在心室中，交替脉尤其危险，因为会有发展为心律失常（如心室颤动）的危及生命的风险。交替脉可在周期性起搏的组织中因起搏本身而形成。最近，已证明通过进行恒定舒张期间隔（DI）起搏可预防这种起搏诱导的交替脉，其中DI与APD无关。然而，在实验环境中实施恒定DI起搏很困难，因为它需要实时测量APD。基于心电图（ECG）提出了一种更实用的方法，通过评估TR间期间接测量整体DI舒张期。此前，我们证明了恒定TR起搏可预防离体Langendorff灌注兔心脏中的交替脉形成。然而，“局部”恒定DI起搏与“全局”恒定TR起搏在预防交替脉形成方面的效果从未被研究过。因此，本研究的目的是在人心室组织的一维数值模型中实施基于ECG的恒定TR起搏，并将心脏组织的动力学行为与恒定DI起搏产生的动力学行为进行比较。结果表明，与周期性起搏相比，恒定TR起搏和恒定DI起搏均能预防交替脉的发生，直至更低的基础周期长度。对于更长的电缆长度，恒定TR起搏对交替脉的控制作用比恒定DI起搏更大。
