Implanted Monitor Aids Arrhythmia Detection in Pregnant Women

By Reuters Staff

February 28, 2020

NEW YORK (Reuters Health) - Compared with standard 24-hour Holter ECG monitoring alone, addition of an implantable loop recorder improves arrhythmia detection in pregnant women with structural heart disease and other abnormalities.

"Persisting structural cardiac abnormalities are associated with arrhythmias, heart failure, and sudden death during pregnancy, with arrhythmias reportedly accounting for up to 31% of cases of maternal death," Dr. Karen Sliwa of the University of Cape Town, in South Africa, and colleagues note in JAMA Cardiology.

Moreover, physiologic changes in pregnancy are known to increase the risk of arrhythmias, the researchers point out, and they may occur for the first time in pregnancy. Pregnancy may also worsen preexisting arrhythmias.

To help determine the best way to monitor arrhythmias, the team enrolled 40 pregnant patients (mean age, 28.4 years) with symptoms of arrhythmia or structural heart disease at risk of arrhythmia.

The women were randomized to standard care, which included 24-hour Holter ECG monitoring, or standard care plus an implantable loop recorder (ILR). After the initial visit the frequency of subsequent visits depended on severity of disease but follow-up data were collected until 42 days after delivery.

The arrhythmias considered included atrial fibrillation, atrial flutter, premature ventricular complexes, supraventricular tachycardia, ventricular tachycardia, and ventricular fibrillation.

Holter monitoring detected arrhythmias in three of 23 patients (13%) in the standard care group and four of 17 patients (24%) in the ILR group. However, ILR detected arrhythmia in nine of the 17 patients (53%), and seven of these (78%) were not detected by Holter monitoring.

Three patients in the ILR group had a change in management as a direct result of the ILR recordings of arrhythmias missed by Holter monitoring.

There were no maternal deaths but the mean gestational stage at delivery was significantly lower in the standard care group (35 weeks) than in the ILR patients (38 weeks).

The researchers concede that the study was small and, "Ideally, Holter monitoring should have been performed for more than 24 hours."

Still, they conclude, "Our findings suggest that ILR may be beneficial for pregnant women at risk of arrhythmia."

Medtronic supported the research and provided the ILR devices, but the researchers reported no conflicts of interest.

Dr. Sliwa did not respond to requests for comments.

SOURCE: JAMA Cardiology, online February 19, 2020.