慢性完全性房室传导阻滞犬心脏性猝死的电生理参数

Electrophysiological parameters indicative of sudden cardiac death in the dog with chronic complete AV-block.

作者信息

van Opstal J M, Verduyn S C, Leunissen H D, de Groot S H, Wellens H J, Vos M A

机构信息

Department of Cardiology, Cardiovascular Research Institute Maastricht, Academic Hospital Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.

出版信息

Cardiovasc Res. 2001 May;50(2):354-61. doi: 10.1016/s0008-6363(01)00226-7.

DOI:10.1016/s0008-6363(01)00226-7

PMID:11334839

Abstract

BACKGROUND

The dog model of chronic complete AV-block (CAVB) demonstrates a considerable incidence of (witnessed) sudden death (16/117 dogs). In this study we tried to: (1) elucidate the mechanisms of sudden death using an ECG telemetry device and (2) identify retrospectively the risk parameters indicative of this arrhythmogenic death.

METHODS

Between 1994 and 1998, 78 anesthetized dogs underwent an extensive electrophysiological study including: (1) left- (LV) and right ventricular (RV) monophasic action potential (MAP) recordings to assess Delta MAPD (LV APD minus RV APD) and (2) pacing protocols (PES) to induce torsade de pointes arrhythmias (TdP) at 4--6 weeks CAVB. Eight animals experienced sudden cardiac death (SCD) during the follow-up period (mean 7+/-3 weeks CAVB). Since the response of the CAVB dog to class III drugs is not uniform we also made comparisons among the SCD group, TdP drug responders and non-responders. For this purpose we selected all animals which (1) received almokalant (n=15, 0.12 mg/kg/5 min) or ibutilide (n=9, 0.025 mg/kg/5 min) as an additional challenge to induce TdP and (2) had a follow-up period of at least 4 weeks.

RESULTS

Six out of eight SCD dogs showed inducible TdP at baseline. Two of eight dogs had telemetric ECG surveillance and both revealed polymorphic VT as the cause of SCD. Baseline Delta MAPD of the SCD (90+/-15 ms) was significantly higher than the non-SCD group (n=70, 60+/-30 ms). Of the 24 dogs which received class III drugs, 12 belonged to the TdP responder group. Delta MAPD of the TdP responder group (80+/-15 ms) was similar to the SCD group and significantly higher compared to the non-responder group (n=12, 40+/-25 ms). QT-time and cycle length of idioventricular rhythm were not different.

CONCLUSION

In the CAVB dog model, SCD is (1) most probably related to TdP while (2) inducible TdP and the measure of Delta MAPD at baseline indicate susceptibility to SCD.

摘要

背景

慢性完全性房室传导阻滞（CAVB）犬模型显示（目击的）猝死发生率相当高（117只犬中有16只）。在本研究中，我们试图：（1）使用心电图遥测设备阐明猝死机制，以及（2）回顾性确定指示这种致心律失常性死亡的风险参数。

方法

1994年至1998年期间，78只麻醉犬接受了广泛的电生理研究，包括：（1）左心室（LV）和右心室（RV）单相动作电位（MAP）记录，以评估Delta MAPD（左心室动作电位时程减去右心室动作电位时程），以及（2）起搏方案（PES），以在CAVB 4至6周时诱发尖端扭转型室性心律失常（TdP）。8只动物在随访期间发生心脏性猝死（SCD）（平均CAVB 7±3周）。由于CAVB犬对III类药物的反应不一致，我们还对SCD组、TdP药物反应者和无反应者进行了比较。为此，我们选择了所有（1）接受阿尔莫卡兰（n = 15，0.12 mg/kg/5分钟）或伊布利特（n = 9，0.025 mg/kg/5分钟）作为诱发TdP的额外刺激，以及（2）随访期至少4周的动物。

结果

8只SCD犬中有6只在基线时可诱发出TdP。8只犬中有2只进行了心电图遥测监测，两者均显示多形性室性心动过速是SCD的原因。SCD组的基线Delta MAPD（90±15毫秒）显著高于非SCD组（n = 70，60±30毫秒）。在接受III类药物的24只犬中，12只属于TdP反应者组。TdP反应者组的Delta MAPD（80±15毫秒）与SCD组相似，与无反应者组（n = 12，40±25毫秒）相比显著更高。室性自主心律的QT间期和周期长度无差异。