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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 :复极快慢的不同可能是TdP发生率性别差异的主要原因
Objective: To observe the difference of ventricular repolarization time between male and female rabbit ventricular muscles and to explore the relationship between them and the gender difference of TdP. Methods: The hearts of male and female rabbits (8 male and 8 female) were perfused with Tyrode ’s solution, Tyrode’ s solution containing sotalol, and low potassium and sotalol containing sotalol respectively Before and after intravenous infusion of sotalol, the monophasic action potential of the endocardium in rabbits hearts was compared. RESULTS: Before sotalol administration, the pacing cycle (CL) was prolonged from 40 ms to 180 ms. The duration of 90% repolarization (MAPD90) of the monophasic action potentials in the rabbits was (181.0 ± 6.5) ) ms prolonged to (2.14 ± 0.07) ms, an increase of (18.2 ± 8.3)%. The intima MAPD90 in rabbits increased from (186.0 ± 6.3) ms to (2.76 ± 0.08) ms. Increase (48.4 ± 9.4)%. After sotalol treatment, the CL increased from 90 ms to 180 ms and the intima MAPD90 prolonged from (224 ± 0.09) ms to (955 ± 7.6) ms with an increase of 31.7 ± 8.7%). The intimal hyperplasia of MAPD90 was prolonged from (34.0 ± 6.3) ms to (376.0 ± 9.7) ms, with an increase of (60.7 ± 8.5)%. The MAPD90 of female rabbits before and after sotalol were significantly longer than those of male rabbits (P <0.01). Seven female rabbits developed TdP, the incidence rate was 87.5%. One male rabbit developed TdP with a rate of 12.5%. Conclusions: The difference in the rate of repolarization may be the main reason for the gender difference in the incidence of TdP