Friedman Ari, Miles Jeremy, Liebelt Jared, Christia Panagiota, Engstrom Krysthel, Thachil Rosy, Grushko Michael, Faillace Robert T
Medicine, Jacobi Medical Center/Albert Einstein College of Medicine, Bronx, USA.
Cardiology, Montefiore Medical Center, Bronx, USA.
Cureus. 2021 Jan 25;13(1):e12895. doi: 10.7759/cureus.12895.
Background Amiodarone causes less drug-induced torsade de pointes (TdP) compared to other class III antiarrhythmics. Two theories proposed for this finding include that amiodarone has less repolarization heterogeneity, and/or decreases early after depolarization (EADs). Corrected QT (QTc) dispersion as measured on a surface electrocardiogram (ECG) represents spatial heterogeneity of ventricular repolarization. Objective The purpose of this study was to analyze the difference in QT dispersion between amiodarone and other class III antiarrhythmics and to determine the etiology of TdP. Methods This was a retrospective, observational study at Montefiore Medical Center between January 2005 and January 2015. Inclusion criteria were adults >18 years on amiodarone, dofetilide, or sotalol with prolonged QT interval on 12-lead ECG. ECGs were reviewed by three blinded observers. QTc was calculated using the Bazett and Framingham formulas. QTc dispersion was calculated by subtracting the shortest from the longest QTc. Analysis of variance (ANOVA) was applied for comparison between antiarrhythmic groups with Bonferroni correction for multiple comparisons. Results A total of 447 ECGs were reviewed and 77 ECGs met inclusion criteria. The average QT dispersion for amiodarone, dofetilide, and sotalol was 0.050, 0.037, and 0.034, respectively (p=0.006) and the average QTc dispersion by Bazett was 0.053, 0.038, and 0.037 (p=0.008) and by Framingham was 0.049, 0.036, and 0.035 (p=0.009), respectively. Conclusion Our results show that given the increase in QT dispersion seen with amiodarone, heterogeneous ventricular repolarization as measured by QTc dispersion likely does not account for the lower incidence of drug-induced TdP seen with amiodarone. The ability of amiodarone to decrease EADs via sodium-channel blockade is more likely the explanation for its lower incidence of drug-induced TdP.
与其他III类抗心律失常药物相比，胺碘酮引起的药物性尖端扭转型室速（TdP）较少。针对这一发现提出的两种理论包括：胺碘酮的复极异质性较小，和/或减少早期后除极（EADs）。体表心电图（ECG）测量的校正QT（QTc）离散度代表心室复极的空间异质性。目的：本研究旨在分析胺碘酮与其他III类抗心律失常药物之间QT离散度的差异，并确定TdP的病因。方法：这是一项于2005年1月至2015年1月在蒙特菲奥里医疗中心进行的回顾性观察研究。纳入标准为年龄大于18岁、正在服用胺碘酮、多非利特或索他洛尔且12导联心电图显示QT间期延长的成年人。心电图由三名不知情的观察者进行评估。使用Bazett公式和弗雷明汉姆公式计算QTc。QTc离散度通过最长QTc减去最短QTc来计算。应用方差分析（ANOVA）对抗心律失常药物组进行比较，并采用Bonferroni校正进行多重比较。结果：共评估了447份心电图，77份心电图符合纳入标准。胺碘酮、多非利特和索他洛尔的平均QT离散度分别为0.050、0.037和0.034（p = 0.006），Bazett公式计算的平均QTc离散度分别为0.053、0.038和0.037（p = 0.008），弗雷明汉姆公式计算的平均QTc离散度分别为0.049、0.036和0.035（p = 0.009）。结论：我们的结果表明，鉴于胺碘酮使QT离散度增加，通过QTc离散度测量的心室复极异质性可能无法解释胺碘酮引起的药物性TdP发生率较低的现象。胺碘酮通过钠通道阻滞减少EADs的能力更有可能是其药物性TdP发生率较低的原因。
