Why women's hearts beat faster: New gene study reveals key difference behind rhythm disorders

A new Ohio State University study reveals that men and women have different genes driving heart rhythm. This may explain why women have faster heart rates while men are more prone to arrhythmias like atrial fibrillation.

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For decades, doctors have observed that women generally have faster heartbeats than men, while men are more likely to develop irregular rhythms like atrial fibrillation (AFib). A new study from The Ohio State University Wexner Medical Center may finally explain why.

Published in the American Heart Association’s journal Circulation: Arrhythmia and Electrophysiology, the study shows that the sinoatrial node (SAN) — the heart’s natural pacemaker — works differently in men and women at the genetic level.

Researchers found that women’s SAN cells are more active in genes like TBX3 and HCN1, which are associated with faster heart rhythms. In contrast, male hearts showed higher activity in genes related to inflammation and collagen production, which can slow down electrical signals and increase the risk of arrhythmias like AFib.

“We found, for the first time, that gene networks controlling the heart’s pacemaker behave differently depending on sex,” said senior author Dr. Vadim Fedorov, Professor of Physiology and Cell Biology and Corrine Frick Research Chair at Ohio State. “This explains why women have faster heart rates and why men are more vulnerable to serious arrhythmias.”

The research was conducted using donated human hearts from Lifeline of Ohio. Scientists at Ohio State’s Dorothy M. Davis Heart and Lung Research Institute examined the gene activity in the SAN pacemaker cells. They analyzed pathways linked to heart pacing, energy use, inflammation, and tissue remodeling — all crucial for healthy heart rhythm.

Dr. Ning Li, co-author of the study, explained, “Women showed more of the genes that make the heart beat faster, while male hearts had genes that might cause scar-like changes, leading to rhythm issues.”

This study stands out because it used actual human hearts and focused on the biological sex-based differences in gene expression. Previous studies have mostly relied on animal models or broader statistical data without looking deep into SAN-specific genetics.

The new findings may open the door to personalized treatment for heart rhythm disorders with therapies tailored to sex-specific gene activity.

In recent years, a few studies have explored how sex differences affect heart health, especially in AFib treatment outcomes. For example, a 2022 study published in Nature Communications found that male and female hearts respond differently to AFib ablation therapies. But Ohio State’s research is among the first to explain such differences at the molecular level in the SAN itself.