Ventricular arrhythmias in pregnant women with and without structural heart disease: are there differences in outcomes?

It is well established that ventricular arrhythmia (VA) is relatively common during pregnancy and carries different clinical significance depending on the presence or absence of structural heart disease (SHD). In women with SHD, VA more often reflects electrical and hemodynamic myocardial instability and is associated with an increased risk of heart failure, life-threatening tachyarrhythmias, hospitalization, and adverse obstetric and perinatal outcomes. In contrast, in women with a structurally normal heart, VA is predominantly idiopathic and has traditionally been considered benign. However, the physiological changes of pregnancy, including increased circulating blood volume, activation of neurohormonal mechanisms, and alterations in the electrophysiological properties of the myocardium, may modify the course of VA and its potential impact on both maternal and fetal outcomes. Quantitative assessment of arrhythmic burden is therefore of particular importance. VA burden is defined as the proportion of ventricular ectopic complexes relative to the total number of heartbeats during the monitoring period and is assessed primarily by Holter ECG monitoring. Recent studies in pregnant women without SHD suggest a possible association between a high VA burden and certain obstetric and fetal/neonatal complications; however, the threshold values associated with individual adverse outcomes vary considerably. Current pregnancy risk stratification models, including mWHO 2.0 and CARPREG II, do not incorporate ventricular ectopic burden as an independent parameter. This review compares data from studies including pregnant women with VA both with and without SHD, discusses potential mechanisms underlying adverse outcomes and the role of serial Holter ECG monitoring, and highlights the limitations of the current evidence base. Prospective studies with standardized assessment of arrhythmic burden, evaluation of VA dynamics across pregnancy trimesters, and long-term postpartum follow-up are needed to identify new risk predictors and improve individualized risk stratification