Following the presentation of real-world data at HRS 2026, Ridhima Kapoor, MD, details the importance of using continuous 14-day ECG patches to capture arrhythmia burden in pregnant populations.
The analysis demonstrated that although nearly 38% of pregnant patients experience arrhythmias, 59.6% of these events are first detected after the standard 48-hour monitoring window. These findings challenge the efficacy of traditional short-duration Holter monitors, which would fail to detect 66.7% of clinically significant arrhythmias in this population.
The study, which utilized Zio ambulatory ECG devices, found that clinically significant arrhythmias—including atrial fibrillation, supraventricular tachycardia, and heart block—were present in 13.6% of patients. Despite the physiological changes associated with pregnancy, the technology maintained a median analyzable time of 99.2%, ensuring high-quality diagnostic data throughout the 14-day period. Researchers emphasized that with cardiovascular disease remaining a leading cause of pregnancy-related mortality in the US, accurate and timely detection of rhythm abnormalities is critical for both maternal and fetal health.
For a deeper analysis of these findings and their implications for obstetric and cardiological care, Contemporary OB/GYN conducted a Q&A email interview with Ridhima Kapoor, MD, clinical assistant professor of cardiovascular medicine at Stanford University, who served as an investigator and presenting author on the study.
Contemporary OB/GYN:
To start, what were the most important findings from your analysis regarding arrhythmia detection in pregnancy, particularly the timing of when these events were identified?
Ridhima Kapoor, MD:
There are 3 key takeaways from this analysis.
First, arrhythmias were detected in approximately 38% of pregnant patients in this cohort, including many without structural or known heart disease. This shows that arrhythmias can occur even in patients without prior cardiac history and underscores the need for evaluation when symptoms arise.
Second, clinically significant arrhythmias were identified in about 14% of patients, a meaningful proportion with rhythm abnormalities that may warrant clinical attention. Notably, the yield of clinically significant arrhythmias was highest in the second trimester, at 16.8%, when hemodynamic and autonomic changes of pregnancy are most pronounced.
Third, the majority of clinically significant arrhythmias were detected after 48 hours of monitoring. This highlights the impact of monitoring duration, particularly for intermittent arrhythmias that may not be captured in shorter monitoring windows.
Contemporary OB/GYN:
Your study found that arrhythmias occurred in more than one-third of pregnant patients, with clinically significant events in nearly 1 in 7. How should providers interpret these rates in the context of routine prenatal care?
Kapoor:
These rates are clinically meaningful and suggest that arrhythmias in pregnancy are more common than previously recognized. A detection rate approaching 38%, with clinically significant events in roughly 1 in 7 patients, including those without structural heart disease, indicates that arrhythmias are not confined to patients with known cardiac risk factors and may be underappreciated in otherwise healthy pregnancies.
In the context of routine prenatal care, this means providers should have a low threshold to consider cardiac rhythm monitoring for commonly reported symptoms such as palpitations, near-syncope, or syncope. Patient-level risk factors should also be taken into consideration, such as advanced maternal age—nearly 25% of our cohort was 35 years or older—a group with higher baseline cardiovascular risk.
Given that cardiovascular disease remains a leading contributor to pregnancy-related complications, improved detection of arrhythmias may play an important role in supporting maternal care.
Contemporary OB/GYN:
A key finding was that the majority of clinically significant arrhythmias were detected after 48 hours. What does this suggest about the limitations of traditional 24- to 48-hour Holter monitoring?
Kapoor:
This finding suggests that monitoring limited to 24 to 48 hours may not detect clinically significant arrhythmias. This could result in falsely reassuring studies, delayed diagnoses, or repeat testing. In our cohort, two-thirds of clinically actionable arrhythmias were first detected after 48 hours.
Clinically, this underscores how monitoring duration directly affects the likelihood of making a diagnosis. Extended, continuous monitoring, such as up to 14 days with the Zio ambulatory ECG, increases the diagnostic yield for clinically significant arrhythmias.
Contemporary OB/GYN:
How might extended monitoring—up to 14 days—change clinical decision-making or management for pregnant patients presenting with symptoms like palpitations?
Kapoor:
Palpitations are commonly reported during pregnancy. Based on history alone, it can be difficult to determine if these are associated with cardiac arrhythmia or not. Extended, continuous monitoring can enable detection of arrhythmias that may not be captured in shorter monitoring windows, helping to guide next steps, whether reassurance, closer monitoring, or referral for further evaluation.
Contemporary OB/GYN:
Taken together with the post-ablation data showing missed atrial fibrillation recurrences, what broader implications do these findings have for how clinicians approach cardiac monitoring across different patient populations?
Kapoor:
These findings point to a consistent theme: Monitoring approach and duration meaningfully influence what we detect. In our pregnancy cohort, the majority of clinically significant arrhythmias emerged after the 48-hour mark. In post-ablation populations, shorter monitoring windows have similarly been shown to underestimate atrial fibrillation recurrence.
Across patient populations, whether pregnant patients [are being] evaluated for palpitations or post-ablation patients [are] being assessed for recurrence, these findings reinforce that matching monitoring duration to the clinical question is essential for accurate detection.
Contemporary OB/GYN:
Is there anything else you would like to include?
Kapoor:
One important point is that many of the patients in this analysis did not have identified structural heart disease, which highlights that clinically significant arrhythmias can be identified even in patients without prior cardiac history.
As ambulatory ECG monitoring continues to evolve, it offers an opportunity to improve the detection of arrhythmias during pregnancy and better inform maternal care.
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