P2533Prospective randomized study on implanted cardiac rhythm recorders in pregnant women with symptomatic arrhythmia and/or structural heart disease

Abstract

Abstract Background Cardiac arrhythmia is an important cause of maternal morbidity and mortality in pregnancy, but is difficult to diagnose. Purpose The aim of this single-centre, prospective, randomized pilot study was to compare the implantable loop recorder (ILR) with standard assessment of arrhythmia (12-lead ECG; 24-hour Holter ECG) in terms of acceptability, detection of arrhythmias and impact on outcome in pregnant women with symptomatic arrhythmias and/or structural heart disease (SHD). Methods The study recruited 40 consecutive patients from a weekly, dedicated cardiac obstetric clinic. Inclusion criteria: symptoms of arrhythmia and/or having SHD at risk of arrhythmia. Patients were randomized to either standard care (SC) or standard care plus ILR (SC-ILR). ILR recordings were read at the monthly visits and/or when presenting with symptoms. Results There were no demographic differences between the study groups. Seventeen patients consented to ILR insertion, all of whom found the procedure acceptable. No arrhythmias were recorded by the 12-lead ECGs. Holter monitoring detected arrhythmias in 10 of 23 patients (43%) from the SC group. In the SC-ILR group, 8 of 17 patients (47%) had arrhythmias detected by Holter, whereas 13 of 17 patients (76%) patients had arrhythmias detected by ILR (p=0.157). One of 4 patients with supraventricular tachycardia, 2 of 3 patients with premature ventricular complexes and 2 patients with paroxysmal atrial fibrillation (AF) recorded by ILR did not have the arrhythmias detected by Holter monitoring (Figure 1A shows a scatter plot of the variable R-R intervals seen in AF and 1B a rhythm strip of AF with irregular RR intervals and the absence of P waves, both downloaded from the ILR). Four of these 5 patients (80%) had a change in management as a direct result of their ILR recordings. There were no maternal deaths up to 42 days postpartum in either of the study groups. Nine babies were born with a low birthweight (<2500g), 5 stillbirth/neonatal deaths and 1 pregnancy termination occurred (5 in the Holter group and 1 in ILR group, p=0.37). Figure 1 Conclusion(s) This study suggests that an ILR is an acceptable diagnostic modality in pregnant women with a suspected or at risk of arrhythmia. The ILR increased the diagnostic yield to detect arrhythmias that were not detected by routine ECG and Holter monitoring which led to a change in management in the SC-ILR group and was associated with better maternal and neonatal outcomes. The impact of ILR monitoring should be further assessed in larger studies with longer follow up.