心室肌复极快慢与尖端扭转型室性心动过速发生率的性别差异

Repolarization duration and gender difference in risk torsade de pointes

目的 :观察雌雄兔离体心室肌复极时程的差异 ,探讨其与尖端扭转型室性心动过速 (TdP)性别差异的关系。方法 :以Langendorff法依次用台氏液、含索他洛尔的台氏液和含索他洛尔的低钾、镁台氏液灌流离体兔(雌雄各 8只 )心 ,记录雌、雄兔心用索他洛尔前后心内膜单相动作电位 ,比较雌雄兔在低钾、镁台氏液灌流后TdP发生率的差异。结果 :用索他洛尔前 ,起搏周期 (CL)从 4 0 0ms延长至 180 0ms,雄兔内膜单相动作电位时程复极90 %的时限 (MAPD90 )由 (181.0± 6 .5 )ms延长到 (2 14 .0± 7.5 )ms ,增幅 (18.2± 8.3) % ;雌兔内膜MAPD90 由(186 .0± 6 .3)ms延长至 (2 76 .0± 8.2 )ms。增幅 (48.4± 9.4 ) %。用索他洛尔后 ,CL从 4 0 0ms增至 180 0ms,雄兔内膜MAPD90 由 (2 2 4 .0± 6 .9)ms延长到 (2 95 .0± 7.6 )ms ,增幅 (31.7± 8.7) % ;雌兔内膜MAPD90 由 (2 34.0±6 .3)ms延长至 (376 .0± 9.7)ms,增幅 (6 0 .7± 8.5 ) %。用索他洛尔前后雌兔内膜MAPD90 均明显长于雄兔 (P<0 .0 1)。 7只雌兔发生TdP ,发生率 87.5 % ;1只雄兔发生TdP ,发生率 12 .5 %。结论

Objective:To investigate the difference of repolarization duration between male and female rabbit ventricle in vitro, and the relationship between gender difference and repolarization duration or torsade de pointes.Methods:Male(n=8) and female(n=8) rabbit heart were perfused by the Langendorff method. 90% of monophasic action potential duration (MAPD 90 ) was measured at apical endocardium of left ventricle at 6 kind of cycle length in control and sotalol(1×10 -4 mol/L) respectively. The repolarization duration and incidence of early after depolarization(EAD) were compared between male and female rabbit heart.Results:In control, hearts were paced at 400,800,1000,1200,1500 and 1 800ms in turn. MAPD 90 of male increased from ( 181.0 ± 6.5 ) ms to ( 214.0 ± 7.5 ) ms and that of female increased from ( 186.0 ± 6.3 ) ms to ( 276.0 ± 8.2 ) ms. After perfusing with sotalol, MAPD 90 of male increased from ( 224.0 ± 6.9 ) ms to ( 295.0 ± 7.6 ) ms and that of female increased from ( 234.0 ± 6.3 ) ms to ( 376.0 ± 9.7 ) ms. EAD developed in 3 female rabbit but none of male rabbit.Conclusion:Repolarization was slower in female rabbit heart than that in male, and the difference was increased by sotalol. Futhermore, more EAD developed in female than that in male.