Mobile Cardiac Telemetry Use to Predict Adverse Pregnancy Outcomes in Patients With Congenital Heart Disease.

Background: Patients with congenital heart disease (CHD) have a higher incidence of arrhythmias during pregnancy, yet the utility of mobile cardiac telemetry (MCT) to predict adverse outcomes is unknown. Objectives: The purpose of this study is to determine whether arrhythmias on screening MCT correlate with adverse pregnancy outcomes. Methods: Patients with CHD prospectively enrolled in the Standardized Outcomes in Reproductive Cardiovascular Care initiative underwent 24-hour MCT (within 18 months prior to pregnancy). Positive findings on MCT were defined as episodes of bradyarrhythmia, symptomatic atrioventricular block, ectopic atrial or ventricular activity, and supraventricular or ventricular tachycardia. Clinically significant arrhythmia events (CSAEs) were those requiring medical or device intervention or an emergency room visit. Clinical events during the antepartum, intrapartum, and postpartum periods were compared using Fisher's exact test. Analyses were performed using Stata version 16. Results: In 141 pregnancies in 118 patients with CHD, MCT detected positive findings in 17%. Adverse cardiac outcomes occurred in 11% of pregnancies, of which CSAE occurred in 3.5%. Positive MCT was significantly associated with subsequent CSAE (21% vs 0%, Conclusions: Patients with CHD had a high rate of positive MCT findings. This was associated with CSAE and adverse maternal cardiac outcomes. Patients with ≥moderate CHD complexity may benefit from screening MCT to improve preconceptual counseling and planning.