动物模型,心率失常 z-bo 2020-07-29 613

　　For different experimental purposes, different arrhythmias can be reproduced in the whole animal. Alternatively, arrhythmia can be reproduced by in vitro perfusion of an isolated heart or a specific part of the heart. There are several commonly used methods of copying.

　　1, atrial flutter and fibrillary arrhythmia

　　Select dogs, cats and other animals, open the chest cavity after anesthesia, expose the heart, and conduct experiments under artificial respiration. High-frequency electricity can be used to directly stimulate the atrial wall, generating R or S wave intervals between each repolarization of the atrial muscle. The aconitine solution is applied to the outside of the atrium. The animal is pressed between the superior vena cava and the inferior vena cava with electrical stimulation; acetylcholine or thyroxine preparations are injected into the atrial node artery. Or, with the chest closed, use the animal to block the respiratory tract or inhale hypoxic gas. The separated atrial tissue block can also be used as an experiment in which a mammalian separated atrial tissue block containing sinus nodes is immersed in a low potassium solution.

　　2. Ventricular tachycardia and ventricular fibrillation arrhythmia often use dogs, cats, rabbits, rats and other whole hearts (open or closed) for experiments. Commonly used styling drugs are aconitine, digitalis and epinephrine. Aconitine is usually given as a slow intravenous injection. Dosage: 100-150μg/kg for rabbits, 30-50mμg for rats, 5mμg for mice. You can also use a toxic dose of digitalis. High concentrations of epinephrine (40μg/kg for guinea pigs and 100μg/kg for cats and dogs) can also be used for rapid intravenous injection. This may lead to premature polygenic contractions and short-term ventricular tachycardia in animals. Such models can be used to screen antiarrhythmic drugs. Its advantage is that the arrhythmia will disappear spontaneously within a few minutes, so that the arrhythmia of the same animal can be tested repeatedly, which can be used to observe the time of action of antiarrhythmic drugs and for self-management.

　　3, atrioventricular block and arrhythmia with normal conduction at the atrioventricular junction

　　mainly choose cats and dogs. Perform anesthesia with the chest cavity open and the heart exposed. Inject thermophysiology into the left ventricular myocardium 1.5-2 cm from the root tip of the dog, and inject 10-15 ml of saline (80-90°C) or 95% Alcohol and 25% sulfuric acid (4-7 ml injection into cats and rabbits) can cause large local myocardial necrotizing arrhythmias. You can also use a needle perpendicular to the junction of the dog's chambers and chambers (ie the left lower atrium, atrium, inferior vena cava, and sulcus of the anterior chamber) to pierce the chambers of the inferior atrial septum. About 0.5 cm above and in front of the intersection). Slowly inject 2-5 ml of 95% or absolute alcohol into the lymph node area, causing nuclear tissue necrosis. You can also use a guinea pig to inject 5μg of adenosine into the left atrium through the left atrial appendage. Approximately 1 second after the injection, a typical block II or higher occurred. In more severe cases, the atrioventricular arrest is complete. There is a parallel relationship between residence time and dose, and heart rate and rhythm can be restored in a few seconds or 10 seconds. Although this model has good repeatability, its conduction block duration is short and it is not easy to use for drug observation. If a large amount of adenosine is injected, the recovery of the conduction block is not easy. Except for guinea pigs, adenosine generally does not cause conduction block in other animals.

　　Four. Use sinus arrhythmia

　　male rabbit, change the thin steel wire into a half ring with a diameter of about 0.8 cm, and wrap it with a small piece of cotton cloth. After infiltration with 40% formaldehyde, the ring is placed at the junction of the root of the superior vena cava and the right atrium for 1 minute. The animal immediately showed changes in the electrocardiogram, the heart rate slowed by about 50%, and dropped to a minimum at about 6-8 minutes. It disappears within 1-2 minutes and forms a critical heart rhythm. Within 3-10 minutes, ST segment deviation (upward, downward or first upward and then downward) occurs. During the replacement process, the arterial pressure decreases. The number of minutes is reduced to a minimum. This method is a very successful, longest duration (up to 5 hours), reproducible and stable model of sinus failure, and its etiology and ECG manifestations are similar to clinical ones.