Changes of Electrical Remodeling in Midmyocardium of Rabbit Left Ventricle with Chronic Pressure-overload

Objective To investigate the changes and significance of electrical remodeling in midmyocardial (M)cells of rabbit left ventricle with chronic pressure-overload.Mothods Thirty-two new Zealand rabbits were randomly divided into constriction group and sham group. The rabbit ventricle models with chronic pressure-overload were prepared by partial constriction of superrenal abdominal aorta. At 8 weeks after operation, the single myocytes were enzymatically isolated from the midmyocardium in the antelateral free wall of left ventricle. Whole cell patch clamp technique was used to record the membrane capacitance, action potential(AP) of M cells.Results At 8 weeks after operation, compared with sham group, the membrane capacitance of M cells from constriction group significantly increased by 34.0%(P0.05). At BCL of 2s, APD90 of M cells in constriction group was 30.6% longer than that in sham group(P0.05). Furthermore, APD of M cells in constriction group presented more pronounced slow frequency-dependence and were easier to produce early afterdepolariztion(EAD). Conclusion During the early phase of chronic pressure-overload, electrical remodeling of M cells from rabbit left ventricle developed,which could be a risk factor for the occurrence of arrhythmia.