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This protocol presents a model of long-term ventricular fibrillation in rat hearts induced by continuous stimulation with low-voltage alternating current. This model has a high success rate, is stable, reliable, and reproducible, has a low impact on cardiac function, and causes only mild myocardial injury.
Ventricular fibrillation (VF) is a fatal arrhythmia with a high incidence in cardiac patients, but VF arrest under perfusion is a neglected method of intraoperative arrest in the field of cardiac surgery. With recent advances in cardiac surgery, the demand for prolonged VF studies under perfusion has increased. However, the field lacks simple, reliable, and reproducible animal models of chronic ventricular fibrillation. This protocol induces long-term VF through alternating current (AC) electrical stimulation of the epicardium. Different conditions were used to induce VF, including continuous stimulation with a low or high voltage to induce long-term VF and stimulation for 5 min with a low or high voltage to induce spontaneous long-term VF. The success rates of the different conditions, as well as the rates of myocardial injury and recovery of cardiac function, were compared. The results showed that continuous low-voltage stimulation induced long-term VF and that 5 min of low-voltage stimulation induced spontaneous long-term VF with mild myocardial injury and a high rate of recovery of cardiac function. However, the low-voltage, continuously stimulated long-term VF model had a higher success rate. High-voltage stimulation provided a higher rate of VF induction but showed a low defibrillation success rate, poor recovery of cardiac function, and severe myocardial injury. On the basis of these results, continuous low-voltage epicardial AC stimulation is recommended for its high success rate, stability, reliability, reproducibility, low impact on cardiac function, and mild myocardial injury.
Cardiac surgery is usually performed via thoracotomy, with blocking of the aorta and perfusion with a cardioplegic solution to arrest the heart. Repeat cardiac surgery can be more challenging than the initial surgery, with higher complication and mortality rates1,2,3. Furthermore, the conventional median sternotomy approach may cause damage to the bridge vessels behind the sternum, the ascending aorta, the right ventricle, and other important structures. Extensive bleeding due to the separation of connective tissue, sternal wound infection, and sternal osteomyelitis ....
All the experimental procedures and protocols used in this investigation were reviewed and approved by the Animal Care and Use Committee of PLA General Hospital.
1. Preparing the Langendorff apparatus
A total of 57 rats were used in the experiments, of which 30 fulfilled the inclusion criteria. The included animals were divided into five groups, with six animals in each group: the control group (Group C), the low-voltage continuously stimulated long-term VF group (Group LC), the high-voltage continuously stimulated long-term VF group (Group HC), the low voltage-induced spontaneous long-term VF group (Group LI), and the high voltage-induced spontaneous long-term VF group (Group HI). The experimental process for each gr.......
This protocol establishes an animal model of long-term VF in isolated rat hearts that has not been previously reported. Additionally, different electrical stimulation conditions were compared in this study. This study provides a model for studies related to ventricular fibrillation arrest during cardiac surgery.
The success rate of the model is a very important indicator that is related to personnel, time, and economic costs. In VF models, the success rate includes whether VF can be induced in.......
This work was carried out with the support of Cardiovascular Surgery, First Medical Center, Chinese PLA General Hospital and the Laboratory Animal Center, Chinese PLA General Hospital.
....Name | Company | Catalog Number | Comments |
0 Non-absorbable suture | Ethicon, Inc. | Preparation of the isolated heart | |
95% O2 + 5% CO2 | Beijing BeiYang United Gas Co., Ltd. | K-H buffer | |
AcqKnowledge software | BIOPAC Systems Inc. | Version 4.2.1 | Software |
Automatic biochemistry analyzer | Rayto Life and Analytical Sciences Co., Ltd. | Chemray 800 | CK-MB assay |
BIOPAC research systems | BIOPAC Systems Inc. | MP150 | Hardware |
Blunt needle (20 G, TWLB) | Tianjin Hanaco MEDICAL Co., Ltd. | H-113AP-S | Modified Langendorff perfusion system |
Calcium chloride | Sinopharm Chemical Reagent Co.,Ltd | 10005861 | K-H buffer |
CK-MB assay kits | Changchun Huili Biotech Co., Ltd. | C060 | CK-MB assay |
Curved forcep | Shanghai Medical Instrument (Group) Co., Ltd. | Preparation of the isolated heart | |
EDTA | Sinopharm Chemical Reagent Co.,Ltd | 10009717 | K-H buffer |
Electrical stimulator | BIOPAC Systems Inc. | STEMISOC | Hardware |
Filter | Tianjin Hanaco MEDICAL Co., Ltd. | H-113AP-S | |
Glucose | Sinopharm Chemical Reagent Co.,Ltd | 63005518 | K-H buffer |
Heparin sodium | Tianjin Biochem Pharmaceutical Co., Ltd. | H120200505 | Preparation of the isolated heart |
Isoflurane | RWD Life Science Co.,LTD | 21082201 | Preparation of the isolated heart |
Magnesium sulfate | Sinopharm Chemical Reagent Co.,Ltd | 20025118 | K-H buffer |
Needle electrodes | BIOPAC Systems Inc. | EL452 | Hardware |
Ophthalmic clamp | Shanghai Medical Instrument (Group) Co., Ltd. | Preparation of the isolated heart | |
Ophthalmic forceps | Shanghai Medical Instrument (Group) Co., Ltd. | Preparation of the isolated heart | |
Ophthalmic scissors | Shanghai Medical Instrument (Group) Co., Ltd. | Preparation of the isolated heart | |
Perfusion tube | Tianjin Hanaco MEDICAL Co., Ltd. | H-113AP-S | Modified Langendorff perfusion system |
Potassium chloride | Sinopharm Chemical Reagent Co.,Ltd | 10016318 | K-H buffer |
Sodium bicarbonate | Sinopharm Chemical Reagent Co.,Ltd | 10018960 | K-H buffer |
Sodium chloride | Sinopharm Chemical Reagent Co.,Ltd | 10019318 | K-H buffer |
Sodium dihydrogen phosphate dihydrate | Sinopharm Chemical Reagent Co.,Ltd | 20040718 | K-H buffer |
Sprague-Dawley (SD) rats | SPF (Beijing) biotechnology Co., Ltd. | Male, 300-350g | Preparation of the isolated heart |
Thermometer | Jiangsu Jingchuang Electronics Co., Ltd. | GSP-6 | Modified Langendorff perfusion system |
Tissueforceps | Shanghai Medical Instrument (Group) Co., Ltd. | Preparation of the isolated heart | |
Tissue scissors | Shanghai Medical Instrument (Group) Co., Ltd. | Preparation of the isolated heart | |
Toothed forceps | Shanghai Medical Instrument (Group) Co., Ltd. | Preparation of the isolated heart | |
Ventilator | Chengdu Instrument Factory | DKX-150 | Preparation of the isolated heart |
Water bath1 | Ningbo Scientz Biotechnology Co.,Ltd. | SC-15 | Modified Langendorff perfusion system |
Water bath2 | Shanghai Yiheng Technology Instrument Co., Ltd. | DK-8D | Modified Langendorff perfusion system |
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