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目的探讨犬单次短时间心室颤动(SDVF)和多次SDVFs后体内肿瘤坏死因子α(TNF-α)及脑钠肽(BNP)的变化及其与除颤阈值(DFT)的关系。方法将144道(12×12,间距2 mm)自制电极片缝至比格犬(n=7)左室前侧壁,用于心外膜刺激和电生理标测。通过心外膜电极行30次快速脉冲(30 Hz)刺激诱发心室颤动(VF)。经颈内静脉置入除颤电极,每次VF持续20 s后给予除颤,用能量递增、递减方法测定DFT。分别于基础状态下,开胸后30 min,第一次SDVF后5 min和多次SDVFs后留取动脉血。ELISA法测定血浆TNF-α及BNP的浓度。评估VF后TNF-α和BNP短时间内的变化,以及与DFT的关系。结果基础状态与开胸后TNF-α和BNP浓度无差异。与基础状态相比,第一次SDVF后血中BNP(78±12.2μg/L vs 90±4.3μg/L,P=0.031)及TNF-α(547±104 ng/L vs 661±151 ng/L,P=0.036)浓度显著降低。多次SDVFs(3.43±0.73次)后,BNP及TNF-α水平有升高趋势,但与基础状态、单次SDVF后相比均无差异。DFT前血浆BNP水平与DFT呈正相关(r=0.76,P=0.046)。结论单次SDVF后,血浆TNF-α及BNP浓度降低,多次SDVFs后两者浓度无明显变化。DFT前BNP水平与DFT呈正相关,提示心功能受损可能导致DFT升高。
Objective To investigate the changes of tumor necrosis factor α (TNF-α) and brain natriuretic peptide (BNP) in dogs with single short-term ventricular fibrillation (SDVF) and multiple SDVFs and its relationship with defibrillation threshold (DFT). Methods Seventy-four (12 × 12, 2 mm) electrodes were stitched to the left anterior wall of beagle dogs (n = 7) for epicardial stimulation and electrophysiological mapping. Ventricular fibrillation (VF) was induced by 30 rapid pulses (30 Hz) through the epicardial electrode. The defibrillation electrodes were implanted through the internal jugular vein, defibrillation was given after each VF for 20 s, and the DFT was determined by energy increment and decrement. At baseline, 30 min after thoracotomy, 5 min after the first SDVF and several SDVFs, arterial blood was collected. Plasma concentrations of TNF-α and BNP were measured by ELISA. The changes of TNF-α and BNP in a short time after VF were evaluated, and the relationship with DFT. Results There was no difference between the basal state and the concentrations of TNF-α and BNP after thoracotomy. BNP (78 ± 12.2 μg / L vs. 90 ± 4.3 μg / L, P = 0.031) and TNF-α (547 ± 104 ng / L vs 661 ± 151 ng / L, P = 0.036) significantly decreased. After multiple SDVFs (3.43 ± 0.73 times), the levels of BNP and TNF-αwere increased, but no difference compared with the basal state and single SDVF. The plasma BNP level before DFT was positively correlated with DFT (r = 0.76, P = 0.046). Conclusion After a single SDVF, plasma TNF-α and BNP concentrations decreased, after repeated SDVFs two concentrations did not change significantly. DFT before BNP levels and DFT was positively correlated, suggesting that impaired cardiac function may lead to elevated DFT.