Murakawa Y, Yamashita T, Kanese Y, Omata M
Second Department of Internal Medicine, University of Tokyo, Japan.
J Am Coll Cardiol. 1997 Mar 1;29(3):688-92. doi: 10.1016/s0735-1097(96)00559-1.
We tested whether a new class III drug (MS-551) administered during ventricular fibrillation (VF) could decrease the defibrillation threshold (DFT) in anesthetized canine hearts.
Pretreatment with class III antiarrhythmic agents is known to enhance electrical defibrillation efficacy.
In a preliminary study (n = 10), we ascertained the validity of DFT determination by a sequence of incremental defibrillation shocks in a single fibrillation/defibrillation episode. We then compared the DFTs after 130 s of VF with and without administration of MS-551 (2 mg/kg body weight) at 10 s after the onset of VF in 12 open chest dogs and 8 closed chest dogs.
MS-551 decreased the DFT in both experimental models (open chest [mean +/- SD]: from 416 +/- 106 to 318 +/- 92 V, p < 0.05; closed chest: from 714 +/- 75 to 615 +/- 112 V, p < 0.05). The change (delta) in DFT in each heart was inversely correlated with the drug-induced prolongation of VF cycle length before the defibrillation attempt (delta DFT vs. delta VF cycle length 10 s before the first discharge: r = -0.58 and -0.81, p < 0.05).
MS-551 given after the induction of VF improved defibrillation efficacy. Class III antiarrhythmic agents deserve consideration when VF is resistant to electrical defibrillation during cardiopulmonary resuscitation.
我们测试了在室颤（VF）期间给予一种新型III类药物（MS - 551）是否能降低麻醉犬心脏的除颤阈值（DFT）。
已知使用III类抗心律失常药物进行预处理可提高电除颤效果。
在一项初步研究（n = 10）中，我们通过在单次颤动/除颤发作中进行一系列递增除颤电击来确定DFT测定的有效性。然后，我们比较了12只开胸犬和8只闭胸犬在VF发作10秒后给予和未给予MS - 551（2mg/kg体重）130秒后的DFT。
在两个实验模型中，MS - 551均降低了DFT（开胸[均值±标准差]：从416±106V降至318±92V，p < 0.05；闭胸：从714±75V降至615±112V，p < 0.05）。每颗心脏DFT的变化（Δ）与除颤尝试前药物诱导的VF周期长度延长呈负相关（首次放电前10秒的ΔDFT与ΔVF周期长度：r = -0.58和 -0.81，p < 0.05）。
VF诱导后给予MS - 551可提高除颤效果。在心肺复苏期间VF对电除颤有抵抗时，III类抗心律失常药物值得考虑。
