Objectives: Pregnancy-related physiological adaptations result in increased heart rate as well as electrocardiographic changes such as a mean QTc prolongation of 27 ms. Pregnant women with CHD are at increased risk for cardiovascular complications. The aim of this study was to identify risk factors for abnormally prolonged QTc interval—a risk factor for ventricular arrhythmias—in pregnant women with CHD. Material and method: Retrospective longitudinal single-centre study. Pre-pregnancy demographic and electrocardiographic risk factors for abnormal QTc duration during pregnancy of (a) > 460 ms and (b) >27 ms increase were analyzed. Results: Eighty-three pregnancies in 63 women were included, of which three had documented arrhythmias. All five Modified World Health Organization Classification of Maternal Cardiovascular Risk (mWHO) classes were represented, with 15 pregnancies (18.1%) in mWHO class I, 26 (31.3%) in mWHO II, 28 (33.7%) in mWHO II-III, 11 (13.3%) in mWHO III, and three pregnancies (3.6%) in mWHO class IV. Heart rate and QTc interval increased, while QRS duration and PR interval shortened during pregnancy. QTc duration of > 460 ms was associated with increased pre-pregnancy QTc interval, QRS duration, and weight, as well as body mass index. QTc increase of > 27 ms was associated with increased heart rate prior to pregnancy. No significant associations of electrocardiographic changes with mWHO class or CHD type were identified. Conclusion: Increased QTc in pregnant women with CHD was associated with being overweight or having higher heart rate, QRS, or QTc duration prior to pregnancy. These patients should be monitored closely for arrhythmias during pregnancy.

中文翻译：

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冠心病女性妊娠期心电图致心律失常变化

目的：与怀孕相关的生理适应导致心率增加以及心电图变化，例如平均 QTc 延长 27 毫秒。患有先心病的孕妇发生心血管并发症的风险增加。本研究的目的是确定患有 CHD 的孕妇 QTc 间期异常延长（室性心律失常的危险因素）的危险因素。材料和方法：回顾性纵向单中心研究。分析了妊娠期间 QTc 持续时间异常 (a) > 460 ms 和 (b) > 27 ms 增加的孕前人口统计学和心电图危险因素。结果：纳入了 63 名女性的 83 次妊娠，其中 3 名记录有心律失常。世界卫生组织修改后的孕产妇心血管风险分类 (mWHO) 的所有五个类别均得到了体现，其中 mWHO I 级有 15 例妊娠 (18.1%)，mWHO II 级有 26 例 (31.3%)，mWHO II-III 级有 28 例 (33.7%)， mWHO III 级有 11 例（13.3%），mWHO IV 级有 3 例妊娠（3.6%）。怀孕期间心率和 QTc 间期增加，而 QRS 时限和 PR 间期缩短。QTc 持续时间 > 460 ms 与孕前 QTc 间期、QRS 持续时间、体重以及体重指数增加相关。QTc 增加 > 27 ms 与怀孕前心率增加相关。未发现心电图变化与 mWHO 分类或 CHD 类型存在显着关联。结论：患有 CHD 的孕妇 QTc 增加与怀孕前超重或心率、QRS 或 QTc 持续时间较高有关。这些患者在怀孕期间应密切监测心律失常。