Heart rhythm disorders affect millions of people worldwide, but emerging research shows that women often experience different symptoms, face later diagnoses, and respond differently to therapies compared with men. From genetic differences in baseline heart rate to hormone-driven changes in the heart’s electrical activity, gendered variations can influence how arrhythmias like atrial fibrillation (AF), supraventricular tachycardia (SVT), and sick sinus syndrome present and progress.
Despite biological differences, women have historically been underrepresented in clinical trials, meaning the expression of symptoms and many treatment recommendations are extrapolated from male-dominated studies. Heart-conscious organizations and researchers are acknowledging a gender gap that contributes to delayed diagnoses, undertreatment, and poorer outcomes for women with arrhythmias.
The good news is that the research tables have been turning. Growing recognition of sex-specific differences means women can benefit from earlier diagnosis, more personalized therapy, and ultimately better cardiac care.
Biological Differences in Cardiac Electrophysiology
The sinoatrial node (SAN), the heart’s natural pacemaker, operates differently in women and men. Differences in SAN function, which are thought to be genetically determined1, might help explain why heart rates, electrical patterns, and arrhythmia risks vary by sex. Gender-related distinctions include:2
- Resting heart rate: Girls have higher heart rates than boys by age five, likely due to a shorter sinus node refractory period (the time the node needs before it can fire again).
- Recharge intervals: Women’s QT intervals (the time the heart’s electrical system takes to recharge between beats) are typically longer due to the effects of estrogen.
- Structural differences: Men have greater ventricular mass and thicker left ventricular walls, which can influence how electrical signals travel through the heart.
Sounds very scientific, but what does it mean? Fundamental differences shed light on the biological reasons women are more prone to supraventricular tachycardias (SVTs), sick sinus syndrome, and postural orthostatic tachycardia syndrome (POTS), while men are more likely to develop atrial fibrillation (AF) earlier in life. However, as women get older, researchers are finding that the risk to women for developing AF becomes almost equivalent to that of men. Along with that, the risk of experiencing a cardiovascular event also increases.
Women also tend to experience more severe or noticeable symptoms even when their arrhythmias are less common. For example, women with AF often have faster heart rate responses and longer episodes than men experiencing the same condition, with a higher burden of fatigue, palpitations, and reduced quality of life associated with arrhythmias.
AV nodal reentrant tachycardia (AVNRT), the most common type of SVT, is also twice as common in women and often appears at a younger age.3The differences in presentation, for many cardiac issues, can make diagnosis challenging, particularly when “classic” symptoms are based on male physiology.
Researchers have also looked at the role sex hormones have in electrophysiology and arrhythmia risk between men and women. Remember what we said earlier about the longer QT interval in women? Apparently, estrogen prolongs that interval, which can increase susceptibility to certain tachyarrhythmias (fast heart rhythms), but progesterone tends to shorten the QT interval, mitigating some of estrogen’s effects.
Translation? Hormone fluctuations during the menstrual cycle can influence the frequency, duration, and severity of SVTs; on the other side of that coin, menopause and changes in androgen levels also shift arrhythmia risk profiles in women over time.4 Hormones help explain why women are more likely to develop paroxysmal AF (intermittent episodes) and SVTs earlier in life, while men tend to have a higher earlier-in-life incidence of AF.
With the recent FDA stance on removing most black-box warnings5 from various hormone therapies for women, it’s worth noting a key distinction here. Estrogen prolongs the QT interval, which is the time the heart’s electrical system takes to reset between beats. A prolonged QT can increase susceptibility to certain tachyarrhythmias. This effect is more acute in pre-menopausal women or during certain phases of the menstrual cycle, when estrogen levels fluctuate naturally. So, in the context of arrhythmias and natural fluctuations, high estrogen levels can sometimes have a “pro-arrhythmic” effect.
Separately, estrogen therapy in menopausal women has vascular and metabolic benefits: it can improve endothelial function, lipid profiles, and arterial flexibility, which are protective against atherosclerosis and overall cardiovascular disease. This is why hormone replacement therapy (HRT) in postmenopausal women can reduce the risk of some cardiovascular events.
Estrogen’s effects are nuanced – it can influence heart rhythm on one hand, while improving vascular function and reducing long-term cardiovascular risk on the other. Timing, dosage, and hormone formulation are important to consider in balancing these effects. It’s best to consult with a healthcare provider to understand the risks and benefits as they pertain to your unique physiology and health conditions.
Diagnostic Delays and Management
Even when women show clear cardiac symptoms, most research is based on male physiology, so symptom patterns and “textbook” presentations do not always reflect female experiences. As a result, studies show that women are referred later for AF ablation and may have more complex conditions by the time they receive treatment. And while outcomes after ablation are similar between sexes, delayed intervention can result in higher symptom burden and increased procedural risk at the time of treatment.6
Women with AF seem to benefit greatly from anticoagulation to prevent stroke, yet rhythm-control strategies, designed to restore normal heart rhythm, sometimes yield less favorable outcomes compared to men. Again, since clinical trials historically enrolled far more men than women, treatment protocols have to be re-evaluated because they’re primarily based on male physiology and responses. Today, growing evidence shows that considering sex-specific differences can optimize treatment and improve outcomes for women.6
The underrepresentation of women in cardiac electrophysiology trials (and clinical research more broadly) has long limited understanding of diagnosis and management. Policies from the NIH and Office of Research on Women’s Health now require the inclusion of women in research studies, along with analysis of sex-specific outcomes. Although these mandates were implemented in the 1990s, designing and completing rigorous clinical trials takes years. As a result, our knowledge of how heart rhythm disorders specifically affect women is still evolving, even decades later.
Later diagnoses, differences in symptom presentation, and gaps in historical research contribute to undertreatment. By increasing awareness of sex-specific variations, promoting timely interventions, incorporating hormone-informed care, and conducting inclusive research, clinicians can provide women with heart rhythm disorders with more effective and individualized care.
This information is not a substitute for professional medical advice. If you are experiencing a medical emergency or concerning heart dysfunction, call 911.
Dr. Tordini is a part of Florida Medical Clinic Orlando Health
- Ohio State University Wexner Medical Center. (2025, May 15). Study reveals why women tend to have faster heartbeats, men more irregular rhythms. Osu.edu. https://wexnermedical.osu.edu/mediaroom/pressreleaselisting/fedorov-san-research.
- Ganjehei, L., Massumi, A., Nazeri, A., & Razavi, M. (2011). Cardiac arrhythmias in women. Texas Heart Institute journal, 38(2), 157–159. https://pmc.ncbi.nlm.nih.gov/articles/PMC3066817/.
- Zeitler, E. P., Poole, J. E., Albert, C. M., Al-Khatib, S. M., Ali-Ahmed, F., Birgersdotter-Green, U., Cha, Y.-M., Chung, M. K., Curtis, A. B., Hurwitz, J. L., Lampert, R., Sandhu, R. K., Shaik, F., Sullivan, E., Tamirisa, K. P., Santos Volgman, A., Wright, J. M., & Russo, A. M. (2022). Arrhythmias in Female Patients: Incidence, Presentation and Management. Circulation Research, 130(4). https://doi.org/10.1161/circresaha.121.319893.
- Ganjehei, L., Massumi, A., Nazeri, A., & Razavi, M. (2011). Cardiac arrhythmias in women. Texas Heart Institute journal, 38(2), 157–159. https://pmc.ncbi.nlm.nih.gov/articles/PMC3066817/.
- US Food and Drug Administration. (2025, November 10). HHS Advances Women’s Health, Removes Misleading FDA Warnings on Hormone Replacement Therapy. U.S. Food and Drug Administration. https://www.fda.gov/news-events/press-announcements/hhs-advances-womens-health-removes-misleading-fda-warnings-hormone-replacement-therapy.
- Ganjehei, L., Massumi, A., Nazeri, A., & Razavi, M. (2011). Cardiac arrhythmias in women. Texas Heart Institute journal, 38(2), 157–159. https://pmc.ncbi.nlm.nih.gov/articles/PMC3066817/.
