Title :
The ionic mechanism of the phase dependency of cardiac cell excitability stimulated by an electric field: a computer simulation
Author :
Wang, Sining ; Quan, Weilun ; Evans, Steven
Author_Institution :
Long Island Jewish Med. Center, New Hyde Park, NY, USA
Abstract :
The current concept of defibrillation correlates defibrillation threshold to cardiac cell excitation threshold (ET). Previous work has shown a 10-15 ms biphasic waveform preferential window (BWPW), identified in the early diastolic phase of an action potential, where ET of the biphasic waveform (BW) is much lower than that of the monophasic waveform (MW). In this paper we investigated the ionic mechanism behind this phenomenon using computer simulations and found that waveforms of the electrical field which can recruit more h and j gates and can provide enough force to drive the membrane potential over the sodium current threshold lowered the ET. This finding may explain some questions arising from basic research and clinical defibrillation in exciting cardiac tissue using different waveforms.
Keywords :
bioelectric potentials; biomembrane transport; cardiology; digital simulation; physiological models; 10 to 15 ms; Na; Na current threshold; action potential; biphasic waveform preferential window; cardiac cell excitability; cardiac cell excitation threshold; cardiac tissue excitation; clinical defibrillation; computer simulation; defibrillation threshold; early diastolic phase; electric field stimulation; electrical field waveforms; h gates; ionic mechanism; j gates; membrane potential; monophasic waveform; phase dependency; Biomembranes; Cardiac tissue; Cells (biology); Computer simulation; Defibrillation; Drives; Electric shock; Fibrillation; Recruitment; Surface resistance;
Conference_Titel :
Computers in Cardiology, 1996
Conference_Location :
Indianapolis, IN, USA
Print_ISBN :
0-7803-3710-7
DOI :
10.1109/CIC.1996.542512
