| Objective:1. To study the correlation between heart structures and electrophysiological parameters in cardiac hypertrophy of model rat.2. To observe the effects of Shensong Yangxin capsule and Fuzheng Huayu Capsule in improving cardiac hypertrophy in rat.Method:1. We made model of cardiac hypertrophy by banding the abdominal aorta of the rat, then we compared the heart structures of four weeks and eight weeks model-operated rat, using echocardiographic and pathologic techniques,we analyse myocardial fibrosis in eight weeks model-operated rat.2. We assessed the threshold and the duration of ventricular fibrillation of eight weeks model rat through the programmed electrical stimulation in vivo, and observed action potential duration (APD) of eight weeks model rat through electrical stimulation in vitro.3. We studied the relation between electrophysiological parameters and cardiac structure and myocardial fibrosis using multiple linear regression statistics. Electrophysiological parameters were dependent variables, however cardiac structure and myocardial fibrosis parameters were independent variables.4. We divided the rats into five groups, including model group, Sham operation group, Captopril group, Shensong Yangxin group, Fuzheng huayu group. Captopril group was considered as a control group for Chinese medicine groups, and then we compared the electrophysiological parameters of medicine groups to model group.Result:1. Compared with sham operation group after four and eight weeks operation, IVSTd, LVPWTd, LADs, LVM, LVMI of the model group became significantly thick, P<0.01, and LVDd became significantly decreased, P<0.01; Compared with sham operation group, TypeⅠ, typeⅢ, TGF-β1 andⅢ/Ⅰratio were significantly increased after eight weeks of operation, P<0.01; CX43 was significantly decreased after eight weeks of operation, P<0.01; compared with model-four-week group, IVSTd, LVPWTd, LADs, LVM, LVMI of model-eight-week group were significantly increased, and LVDd had no difference, P>0.05.2. Compared with sham operation group, APD90, ERP, ERP/APD90 of left ventricular of model-eight-week group became significantly increased, P<0.01;3. The statistics approach of multiple linear regression showed that threshold and the duration of ventricular fibrillation had negative correlation with LVPWTd andⅢ/Ⅰratio, and ERP/APD90 had negative correlation with LVPWTd typeⅢ.4. Compared with molde operation group, IVSTd, LVPWTd of Shensong Yangxin group and Fuzheng Huayu group became significantly thinner. Captopril group had the best effect on inhibition of typeⅠ, typeⅢ, and TGF-β1, P<0.01;5. compared with molde group, the threshold of ventricular fibrillation in Shensong Yangxin group and Fuzheng Huayu group was significantly increased, P<0.01; Shensong Yangxin had significant difference in increasing the time of APD90, ERP, and had better effect in increasing ERP/APD90 ratio than Fuzheng Huayu group and Captopril group, P<0.01;Conclution:1. The model hypertrophic cardiac rat induced by coarctation of abdominal aorta after eight weeks have characteristic of concentric hypertrophy and fibrosis.2. The electrophysiological parameters of the concentric hypertrophy of rat change as the threshold of ventricular fibrillation is decreased, and the duration of ventricular fibrillation, effective refractory period (ERP) and action potential duration (90%) (APD90) all will be prolonged, and ERP/APD90 ratio is decreased.3. The frequency of Ventricular arrhythmia is increased when thickness of the left ventricular posterior wall (LVPW) and collagen amount is increased. The four equations show that there is a correlation between heart structures and electrophysiological parameters in cardiac hypertrophic model rat.4. Shensong Yangxin and Fuzheng Huayu can improve concentric hypertrophy, fibrosis and electrophysiological parameters of cardiac hypertrophic model rat.5. We should pay attention to the relation between hypertrophy of myocardial interstitium and arrhythmia. |
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