Reduced heart rate variability and altered cardiac conduction after pre-eclampsia

Abstract

Pre-eclampsia is a hypertensive disorder of pregnancy that is associated with elevated maternal risk for cardiovascular disease. The aims of this study were to determine the effect of normal pregnancy on postpartum parameters of the electrocardiogram, and furthermore to determine how a history of pre-eclampsia may affect these parameters. Ten-minute highresolution (1000 Hz) orthogonal Holter electrocardiogram (ECG) recordings were used to measure heart rate variability (HRV). Signal-averaged P-wave and QRS complex durations were determined. Participants included non-pregnant controls, normotensive parous controls and women with a recent history of PE. While reductions in HRV induced by uncomplicated pregnancy returned to non-pregnant levels by 6-8 months postpartum HRV remained reduced in women with a history of PE compared to control groups. In addition, PWave and QRS complex durations were prolonged in PE subjects at 6-8 months postpartum compared to control groups. Only QRS duration was independent of differences in blood pressure. These results suggest increased sympathetic cardiac activity, and delayed myocardial conduction in women after PE; alterations consistent with cardiac remodeling and increased risk for arrhythmia. In examining the association between PE and cardiovascular disease, identification of ECG abnormalities soon after pregnancy in women with a history of PE highlights a unique opportunity for early identification and screening in this population before other risk factors become apparent.