New Insights Into Sex Differences in Heart Rhythms: Faster Heartbeats in Women and Irregular Rhythms in Men

A groundbreaking study from The Ohio State University Wexner Medical Center sheds light on the longstanding mystery of why women typically experience faster heart rates, while men are more susceptible to irregular heart rhythms such as atrial fibrillation (AFib). The research reveals that the sinoatrial node (SAN)—the heart's natural pacemaker responsible for initiating each heartbeat—operates differently in men and women due to genetic variations.

The study found that women possess specific genes that promote quicker heartbeats, including higher levels of TBX3 and HCN1, whereas male hearts show increased activity in gene networks linked to inflammation and collagen production, potentially disrupting electrical signaling and increasing arrhythmia risk. These differences stem from sex-specific gene blueprints influencing the SAN's function.

Scientists examined donated human hearts from organ donors to analyze gene expression and pathways involved in pacing, metabolism, inflammation, and fibrotic remodeling. The findings indicate that sex influences how these genes function, providing a molecular explanation for observed clinical patterns.

Vadim Fedorov, Ph.D., explained that understanding these sex-based genetic differences helps clarify why women are more prone to conditions like sinus tachycardia while men face higher risks of conduction block or AFib. This research could pave the way for more personalized treatments targeting these genetic pathways.

The study highlights the importance of considering biological sex in cardiac health and reinforces the potential for developing tailored therapies to prevent and treat rhythm disorders. According to the American Heart Association, over 6 million Americans live with heart failure and rhythm disturbances rooted in the SAN.

This research was published in Circulation: Arrhythmia and Electrophysiology and funded by Ohio State University’s research centers, including the Dorothy M. Davis Heart and Lung Research Institute and the Bob and Corrine Frick Center for Heart Failure and Arrhythmia.