The effects of sotalol on ventricular repolarization during exercise

Objective: Although after pacing animal and human studies have demonstrated a rate-dependent effect of sotalol on ventricular repolarization, there is little information on the effects of sotalol on ventricular repolarization during exercise. This study attempted to show the effects of sotalol on ventricular repolarization during physiological exercise. Methods: Thirty-one healthy volunteers (18 males, 13 females) were enrolled in the study. Each performed a maximal treadmill exercise test according to the Bruce protocol after random treatment with sotalol, propranolol and placebo. Results: Sotalol significantly prolonged QTc (corrected QT) and JTc (corrected JT) intervals at rest compared with propranolol (QTc 324.86 ms vs 305.21 ms, P<0.001; JTc 245.04 ms vs 224.17 ms, P<0.001) and placebo (QTc 324.86 ms vs 314.06 ms, P<0.01; JTc 245.04 ms vs. 232.69 ms, P<0.001). The JTc percent reduction increased progressively with each stage of exercise and correlated positively with exercise heart rate (r=0.148, P<0.01). The JTc percent reduction correlation with exercise heart rate did not exist with either propranolol or placebo. Conclusions: These results imply that with sotalol ventricular repolarization is progressively shortened after exercise. Thus the specific class III antiarrhythmic activity of sotalol, present as delay of ventricular repolarization, may be attenuated during exercise. Such findings may imply the need to consider other antiarrythmic therapy during periods of stress-induced tachycardia.

索他洛尔对运动时QTc和JTc间期的影响

目的探讨生理运动状态下索他洛尔对心室复极作用的影响。方法以随机、双盲、索他洛尔、普萘洛尔和安慰剂进行自身对照,对30例入选的健康志愿者,进行活动平板运动试验;对体表心电图上校正的QT间期(QTc)和校正的JT间期(JTc)进行分析。结果与服普萘洛尔和安慰剂比较,静息状态时索他洛尔对QTc和JTc的延长作用最显著。运动过程中,服索他洛尔、普萘洛尔和安慰剂的QTc和JTc都缩短,其中服索他洛尔的JTc缩短最显著,其JTc的缩短率(ΔJTc%)大于服普萘洛尔和安慰剂(8.83%±6.09%vs2.70%±6.20%和5.73%±5.83%,P<0.001和P<0.05)。并且运动过程中服索他洛尔的ΔJTc%与运动心率呈显著正相关(r=0.148,P<0.01)。结论索他洛尔显著延缓静息状态下的心室复极,在运动过程中与普萘洛尔和安慰剂比较,索他洛尔延缓心室复极的作用呈现出进行性减弱的现象。

民航飞行员心肌桥对心室复极影响的调查

目的调查民航飞行员心肌桥的检出情况及心肌桥飞行员心室复极是否存在异常,探讨心肌桥对心室复极的影响。方法采用回顾性研究,分析2019年≥40岁的民航飞行员次极量平板运动试验资料。排除患有影响心室复极的心血管疾病者。测定飞行员运动前静息心电图及运动结束后1 min QT间期,计算QT间期离散度(QT dispersion,QTd)。根据是否检出心肌桥分为心肌桥组和对照组,对比分析心肌桥组与对照组飞行员的平板运动试验阳性率及室性早搏发生率。对行24 h动态心电图检查者,统计分析QT/RR斜率。结果共有243例飞行员纳入研究,其中男性242例,女性1例。243例民航飞行员中检出心肌桥27例,主要见于左冠状动脉前降支(25/27,92.6%);17例行24 h动态心电图检查,其中心肌桥组6例,对照组11例。心肌桥组飞行员总飞行时间多于对照组,差异有统计学意义(Z=2.29,P=0.022);次极量平板运动试验的阳性率或可疑阳性率及室性早搏的发生率均高于对照组,差异有统计学意义(χ^(2)=52.74、5.78,P<0.001、=0.016);平板运动试验恢复1 min后QTd延长大于对照组,差异有统计学意义(Z=-2.20,P=0.028);24 h室性早搏的平均发生次数、QTe/RR斜率和QTa/RR斜率高于对照组,差异均有统计学意义(t=2.37、4.26、2.51,P=0.034、<0.001、=0.024)。结论飞行员心肌桥可能导致心室复极时间延长,易发生室性心律失常。平时航空卫生保障工作中应重视心肌桥飞行员的体检和飞行适应性评定,尤其要加强对心室复极异常飞行员的日常健康管理,以确保飞行安全。