| Objective:1. To study the effects of autonomic nerve on ventricular fibrillation self-limitation in vivo rabbit heart.2. To study the effects of left ventricular afterload changing on ventricular fibrillation self-limitation in vivo rabbit heart; to study the effects of left ventricular afterload changing on ventricular fibrillation self-limitation, eliminating action of nerves and body fluid by using standard Langendorff technique.3. To study the effects of lidocaine on ventricular fibrillation self-limitation in vivo rabbit heart.Material and method: 1. The effects of autonomic nerve on ventricular fibrillation self-limitationAnaesthetized the New Zealand rabbit with 3% sodium pentobarbital 30mg·kg -1 by abdomen; cut the hair off, cut the skin in the middle of the neck, separated the trachea, put a trachea tube, separated the left common carotid tube to left ventricular, connected pressure transducer and Powerlab data collecting system, for dynamically monitoring the pressure of left ventricular; separated right pneumogastric nerve or sympathetic nerve, cut off, outside connected physiologic experimental multi-use instrument for stimulating use; opened the thorax via thoracotomy along the left edge of the sternum, maintained autonomous breathing and sinus rhythm, exposed the heart, cut the pericardium, sewed pericardium hammock, inserted a ventricular plunge electrode of four electrodes into the left ventricle under the left auricle and beside the anterior interventricular sulcus. The distance between the four electrodes: the 1 2 electrode (a), the 3 4 electrode (b) were all 1.5mm, the 2 3 electrode was 5mm, the 1 2 electrodes or the 3 4 electrodes (connected with SEC-2102 Model Stimulator, and determined relative refractory period and effective refractory period of a and b point.) or the 2 3 electrodes (connected with SEC-2102 stimulator and determined ventricular fibrillation threshold.) were used as stimulating electrodes respectively; atthe same time, the 3 4 electrodes or the 1 2 electrodes or the 1 4 electrodes were used as recording electrodes, inputting the creature electronic signal into Powerlab data collecting system, recorded and kept the data, pierced the needle electrodes into the extremities of rabbit, connected Powerlab data collecting system to record the limb lead electrocardiogram. Every group, before stimulating the sympathetic nerve or pneumogastric nerve, stimulated the sympathetic nerve and pneumogastric nerve (stimulating frequency was 10 Hz or 30 Hz), stimulated sympathetic nerve + metoprolol 0.03mg/kg by intravenous injection or pneumogastric nerve + atropine 0.3mg/kg by intravenous injection (stimulating frequency was 10 Hz or 30 Hz) to determine respectively ventricular diastolic threshold, ventricular relative refractory period, ventricular effective refractory period, refractory period dispersion,heart rate and left ventricular pressure(LVF). Induced ventricular fibrillations with trains' electric impulse and observed the ventricular fibrillation threshold, the changes of the frequency of ventricular fibrillation, height and width of ventricular fibrillation wave, the probability of ventricular fibrillation self-limitation, duration changes of ventricular fibrillation, the changes of left ventricular pressure before and after ventricular fibrillation, during the ventricular fibrillation being induced and stopped; resting time after ventricular fibrillation stopped, the changes of arrhythmias after ventricular fibrillation. 2. The effects of left ventricular afterload changing on ventricular fibrillationself-limitation. l)The effects of left ventricular afterload changing on ventricular fibrillationself-limitation in vivo rabbit heart.Anaesthetized the New Zealand rabbit with 3% sodium pentobarbital 30mg*kg l by abdomen; cut the hair off, cut the skin in the middle of the neck, separated the trachea, put a trachea tube, separated the left common carotid tube to left ventricular, connected pressure transducer and Powerlab data collecting system; opened the thorax via thoracotomy along the left edge of the sternum, maintained autonomous breathing and sinus rhythm, exposed the heart, cut the pericardium, sewed pericardium hammock, inserted a ventricular plunge electrode of four electrodes into the left ventricle underthe left auricle and beside the anterior interventricular sulcus. The distance between the four electrodes: the 1 2 electrode (a), the 3 4 electrode (b) were 1.5mm, the 2 3 electrode was 5mm, the 1 2 electrodes or the 3 4 electrodes (connected with SEC-2102 Model Stimulator, and determined relative refractory period and effective refractory period of a and b point.) or the 2 3 electrodes (connected with SEC-2102 stimulator and determined ventricular fibrillation threshold.) were used as stimulating electrodes respectively; at the same time, the 3 4 electrodes or the 1 2 electrodes or the 1 4 electrodes were used as recording electrodes, inputting the creature electronic signal into Powerlab data collecting system, recorded and kept the data, pierced the needle electrodes into the extremities of rabbit, connected Powerlab data collecting system to record the limb lead electrocardiogram. Slightly separated the root of main artery, mechanically clipped the root of main artery with different self-made main artery clipper by different degrees (clipper diameter is 1.5mm (A degree) and 2.5mm (B degree)), increased the left ventricular afterload with different degrees, used PFA-05 Model transfusion pump to inject sodium nitroprusside, decreased the left ventricular afterload with different degrees (C degree: 21% lower than the standard blood pressure, D degree: 42% lower than standard blood pressure). Measured the VDT, VRRP, VERRRPd, HR, pressure of left ventricular, before and after changing the left ventricular afterload. Induced ventricular fibrillations with trains' electric impulse and observed the ventricular fibrillation threshold, the changes of the frequency of ventricular fibrillation, height and width of ventricular fibrillation wave, the probability of ventricular fibrillation self-control, duration changes of ventricular fibrillation, the changes of left ventricular pressure before and after ventricular fibrillation, during the ventricular fibrillation being induced and stopped; resting time after ventricular fibrillation stopped, the changes of arrhythmias after ventricular fibrillation.2)The effects of left ventricular afterload changing on ventricular fibrillation self-limitation in isolated rabbit heartAnaesthetized the New Zealand rabbit with 3% sodium pentobarbital 30mg?kg "' by abdomen; cut the hair off, cut the skin in the middle, opened the thorax through theleft edge of sternum, maintained the autonomous breathing, first heparinized (injected 500u/kg, by intravenous injection through ear edge), cut pericardium, exposed the heart, then took the heart, carefully cut the vena cava to bleed, cut the main artery and surrounding tissue, put the isolated heart immediately into the iced K-H liquid (0-4°C) with little heparinase, pressed with hand to take the remaining blood out. After taking the heart out, quickly connected its ascending aorta with aorta artery of perfusion system, then tied it. Immediately started Langendorff constant pressure perfusion. Improved K-H perfusion liquid was newly made with perhydrol, per-filled mixed gas 95% O2 + 5% CO2, made its PH value 7.35 7.45, kept the K-H temperature of perfusion liquid 37 + 0. 5° C. During the experiment, K-H perfusion was filled with 95% O2 + 5% CO2 continuously. Inserted a ventricular plunge electrode of four electrodes into the left ventricle under the left auricle and beside the anterior interventricular sulcus, concrete method was the same with vivo rabbit model. Changed the height degree of aorta outflow path (A degree lOOcm^O, B degree 75cmH2O, C degree 50cmH2O), changed the left ventricular afterload, measured the VDT, VRRP, VERP, RPd,HR at a and b point under different load. Induced ventricular fibrillations with trains' electric impulse and observed the ventricular fibrillation threshold, the changes of the frequency of ventricular fibrillation, height and width of ventricular fibrillation wave, the probability of ventricular fibrillation self-limitation, duration changes of ventricular fibrillation, the changes of left ventricular pressure before and after ventricular fibrillation, during the ventricular fibrillation being induced and stopped; resting time after ventricular fibrillation stopped, the changes of arrhythmias after ventricular fibrillation. 3. The effects of lidocaine on ventricular fibrillation self-limitationAnaesthetized the New Zealand rabbit with 3% sodium pentobarbital 30mg?kg "' by abdomen; cut the hair off, cut the skin in the middle of the neck, separated the trachea, put a trachea tube, separated the left common carotid tube to left ventricular, connected pressure transducer and Powerlab data collecting system; opened the thorax via thoracotomy along the left edge of the sternum, maintained autonomous breathing and sinus rhythm, exposed the heart, cut the pericardium, sewed pericardium hammock,inserted a ventricular plunge electrode of four electrodes into the left ventricle under the left auricle and beside the anterior interventricular sulcus. The distance between the four electrodes: the 1 2 electrode (a), the 3 4 electrode (b) were 1.5mm, the 2 3 electrode was 5mm, the 1 2 electrodes or the 3 4 electrodes (connected with SEC-2102 Model Stimulator, and determined RRP and ERP of a and b point.) or the 2 3 electrodes (connected with SEC-2102 stimulator and determined VFT.) were used as stimulating electrodes respectively; at the same time, the 3 4 electrodes or the 1 2 electrodes or the 1 4 electrodes were used as recording electrodes, inputting the creature electronic signal into Powerlab data collecting system, recorded and kept the data, pierced the needle electrodes into the extremities of rabbit, connected Powerlab data collecting system to record the limb lead electrocardiogram. Injected lidocaine 2mg/kg by intravenous injection through ear edge with the speed of 2mg/kg. Measured theVDT, RRP, ERP, RPd,HR, left ventricular pressure of a and b point before and after injection. Induced ventricular fibrillations with trains' electric impulse and observed the ventricular fibrillation threshold, the changes of the frequency of ventricular fibrillation, height and width of ventricular fibrillation wave, the probability of ventricular fibrillation self-limitation, duration changes of ventricular fibrillation, the changes of left ventricular pressure before and after ventricular fibrillation, during the ventricular fibrillation being induced and stopped; resting time after ventricular fibrillation stopped, the changes of arrhythmias after ventricular fibrillation.Result: 1. The effects of autonomic nerve on ventricular fibrillation self-limitationCompared stimulating pneumogastric nerve with before stimulating, when stimulating the pneumogastric nerve (lOHz), VRRP and VERP were prolonged (P<0.05), RRPd and ERPd were shortened ,VFT was increased (PO.05), HR was decreased (P<0.05), VDT had no change; when stimulating the pneumogastric nerve (30Hz), VRRP and VERP were significantly prolonged (P<0.01), RRPd and ERPd were significantly shortened ,VFT was increased (P<0.05), HR was significantly decreased (PO.01), VDT had no change. When stimulating pneumogastric nerve (lOHz and 30Hz) + atropine 0.3mg/kg by intravenous injection, compared with beforestimulating, VRRP, VERP, RRPd, ERPd, VDT, VFT and HR had no change,;compared stimulating pneumogastric nerve with 30Hz and lOHz, VRRP and VERP were prolonged (P<0.05), RRPd and ERPd were shortened ,VFT was increased (P<0.05).75% ventricular fibrillation might be self-limited.Compared stimulating sympathetic nerve with before stimulating, when stimulating the sympathetic nerve (lOHz), VRRP and VERP were decreased (P<0.05), RRPd and ERPd were increased,VFT was decreased (PO.05), HR was increased (PO.05), when stimulating the sympathetic nerve (30Hz), VRRP and VERP were significantly decreased (P<0.01), RRPd and ERPd were significantly increased, VFT was significantly decreased (P<0.01), HR was significantly increased (P<0.01), VDT had no change. When stimulating sympathetic nerve (lOHz and 30Hz) + metoprolol 0.03mg/kg by intravenous injection, VRRP, VERP, RRPd, ERPd, VDT, VFT and HR had no change; compared stimulating sympathetic nerve with 30Hz and lOHz, VRRP and VERP were decreased (P<0.05), RRPd and ERPd were increased,VFT was decreased (P<0.05).50% ventricular fibrillation might be self-limited. 2. The effects of left ventricular afterload changing on ventricular fibrillationself-limitation l)The effects of left ventricular afterload changing on ventricular fibrillationself-limitation in vivo rabbit heart.Compared changing left ventricular afterload with before clipping, A degree VRRP and VERP were significantly shortened (P<0.01), RRPd and ERPd were significantly increased, VFT was significantly decreased (P<0.01), HR and VDT had no change; the left ventricular pressure was significantly increased (P<0.01); B degree VRRP and VERP were shortened (P<0.05), RRPd and ERPd were increased,VFT was decreased (P<0.05), HR and VDT had no change; the left ventricular pressure was increased (P<0.05); C and D degree VRRP, VERP, RRPd,ERPD,HR and VDT had no change; Compared A degree with B degree, VRRP and VERP were shortened (P<0.05), RRPd and ERPd were increased,VFT was decreased (P<0.05), 50% ventricular fibrillation might be stopped by itself at A degree, 75% ventricular fibrillation might be stopped by itself at B degree,87.5% ventricular fibrillation might be stopped by itself at C degreeand D degree.2)The effects of left ventricular afterload changing on ventricular fibrillation self-limitation in isolated rabbit heart.Compared the height of main artery outflow path A degree with C degree, VRRP and VERP were significantly shortened (PO.01), RRPd and ERPd were significantly increased, VFT was significantly decreased (PO.01), VDT had no change; compared the B degree with C degree, VRRP and VERP were shortened (P<0.05), RRPd and ERPd were increased, VFT was decreased (PO.05), VDT had no change. 75% ventricular fibrillation might be stopped by itself at A degree; 87.5% ventricular fibrillation might be stopped by itself at B degree; 100% ventricular fibrillation might be stopped by itself at C degree. 3. The effects of lidocaine on ventricular fibrillation self-limitationCompared with before using the lidocaine, VRRP and VERP at post-drug were prolonged (P<0.05), RRPd and ERPd were shortened (P<0.05),VFT was significantly increased (PO.01), LVF had no change; 87.5% ventricular fibrillation might be stopped by itself. Conclusion:1. In the vivo rabbit heart, stimulating the pneumogastric nerve might have the effects of VRRP and VERP were prolonged, RRPd and ERPd were shortened ,VFT was increased, and have something related with the stimulating frequency, ventricular fibrillation might not be easy to be induced and might be easy to be stopped by itself, stimulating the sympathetic nerve might have the effects of shortening VRRP and VERP, RRPd and ERPd were increased,decreasing VFT, and have something related with the stimulating frequency, ventricular fibrillation might be easy to be anri miaVit tint Tip pasv tn Kp Qtrmnpd Vw itthreshold. In the isolated rabbit heart, increasing left ventricular afterload might decrease VFT, and the ventricular fibrillation might be easy to be induced and might not be easy to be stopped.3. In vivo rabbit heart, lidocaine might have the effects of prolonging VRRP and VERP, RPvPd and ERPd were shortened, increasing the VFT, ventricular fibrillation might not be easy to be induced and might be easy to be stopped by itself.
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