动物造模 z-bo 2022-02-03 457

　　[Modeling mechanism] Rapid atrial pacing atrial fibrillation model is currently the most studied and most widely used animal model of chronic atrial fibrillation. This mechanism is related to electrical and structural remodeling caused by rapid atrial pacing. Various animal models show without exception: the effective atrial refractory period (ERP) is shortened, the frequency adaptability is reduced, the atrial diameter and volume are significantly increased, and the anisotropy is increased. Re-entering multiwave will happen more easily. The main ionic mechanism is to down-regulate the L-type calcium current IC, L, the instantaneous outward potassium current Ito and the delayed rectifier potassium current IK.

　　[How to build a model]

　　(1) Dog: Use 16-30 kg healthy adult dogs. After intravenous anesthesia with sodium pentobarbital (30 mg/kg), use isoflurane (2 mg/kg) and intravenous chloralose (0.3-0.4 mg/kg) to maintain general anesthesia or intramuscular injection of acepromazine. (0.3-0.4mg/kg), 4% halothane, 2L/min of nitrous oxide, 1L/min of oxygen, 2L/min of medical gas inhalation to maintain general anesthesia. Under the guidance of radiography, a 6F quadrupole wire was delivered to the right atrium through the femoral vein to determine the atrial pacing threshold. Give atrium 400 to 800 beats/min, which is 2 to 4 times the threshold voltage S1S1 (300 ms) or S1S2 (S1S1/S1S2 300 ms/200 ms, step length 5 ms reduction scan), pulse width 2 ms programmed stimulation Will induce atrial fibrillation. ..

　　(2) Goat: Use 15-65 kg goats. After intravenous injection of thiopental sodium (10 mg/kg), general anesthesia was maintained by inhalation of halothane (1% to 2%) and a 1:2 mixture of oxygen:nitrogen monoxide. Open the left chest, cut the heart pack, place the electrodes on the left and right atrium epicardial walls of the goat and Bachmann bundle, suture the chest wall, connect the electrodes to the external defibrillator with a frequency of 50 Hz, use a burst of 20 ms Stimulation stimulates multiple parts at the same time, the interval is 1 ms, and the time is 4 times the diastolic threshold. When atrial fibrillation occurs, the stimulation stops, and when the atrial fibrillation changes to a sinus rhythm, the stimulation continues.

　　(3) Other animals: This model can be successfully replicated in mice, rats, rabbits, etc. After the animal is anesthetized, the electrode is placed in the right atrium and high-frequency stimulation is performed. Most animals may cause atrial fibrillation during an attack.

　　[Model Features] Acute high-frequency stimulation can cause atrial fibrillation within 10 seconds to 30 minutes, but chronic high-frequency stimulation for 6 to 8 weeks can reproduce spontaneous atrial fibrillation.. [Model evaluation and application] Rapid right atrium The animal model of atrial fibrillation established by pulsation has a high success rate, high reproducibility and long atrial fibrillation maintenance time. Non-valvular atrial fibrillation, electrophysiological remodeling and remodeling can be used for cardiomyopathy, molecular biology and other clinical research can also be used to study tachycardia and cardiomyopathy. However, extreme care should be taken when controlling ventricular velocity in this way, because too fast ventricular velocity can cause ventricular dysfunction and may cause atrial changes that are not related to rapid atrial pacing.