Microscopic changes within heart cells may play a protective role against irregular heartbeats, according to new research.

Irregular heartbeats,known as arrhythmias,are more prevalent as people age and can lead to various health complications.

A study published in JACC Clinical Electrophysiology indicates that the perinexus,a small gap between heart cells,naturally narrows with age. This adaptation may contribute to stabilizing heart rhythm.

This finding challenges the assumption that all age-related changes in the heart are detrimental.

According to steven Poelzing, a professor at the Fralin Biomedical Research Institute at Virginia Tech, “As we get older and cardiac cells get bigger, the body compensates by making electrical communications more robust.”

“Making sure the dialogue between cells remains high during aging appears to occur naturally to keep cardiovascular disease in check,” Poelzing added.

Poelzing suggests that the body reinforces the structure between cells to strengthen electrical communication,which supports the rapid influx of sodium ions needed to initiate each heartbeat.

Understanding Arrhythmias

Arrhythmias occur when the heart’s electrical signals become too fast, too slow, or disorganized.These irregularities can affect millions globally and range from harmless to life-threatening, increasing the risk of stroke, heart failure, and sudden cardiac arrest.

“As we get older and cardiac cells get bigger, the body compensates by making electrical communications more robust.”

The National Heart, Lung, and Blood Institute reports that atrial fibrillation is the most common arrhythmia, affecting over 2 million adults in the United States, with numbers expected to rise.

To understand how structural changes in the heart affect arrhythmia risk, researchers examined young and old guinea pig hearts, using medication to induce sodium channel gain of function.

The study revealed that older hearts naturally had a narrower perinexus, which seemed to protect against arrhythmias. However, when this space was artificially widened, older hearts quickly developed irregular rhythms, while younger hearts remained stable.

As heart cells enlarge with age, they adhere more tightly, maintaining electrical stability.

“If you can keep cells nicely packed, you can conceal a lot of age-associated cardiac pathologies,” says poelzing, who is also a professor in the biomedical engineering and mechanics department in the Virginia Tech College of Engineering.

Poelzing likened it to a house’s foundation: a solid foundation allows the structure to withstand wear and tear,while an unstable foundation increases risk.

From a clinical standpoint, Poelzing notes that this study explains why arrhythmias can be tough to detect in aging patients.

Cardiologists sometiems refer to heart diseases as “concealed” because the body compensates for electrical instability, returning to normal function before standard tests can detect a problem. Therefore, doctors often use long-term monitoring to detect arrhythmias before the heart re-stabilizes.

An editorial accompanying the study in JACC: Clinical Electrophysiology highlights the delicate balance between perinexus size and electrical activity in the heart. The editorial suggests that targeting perinexus size could lead to new strategies for preventing arrhythmias and improving heart health in aging individuals.

Researchers from Virginia Tech and Ohio State University also contributed to the work.

The research received support from the National Heart, Lung, and Blood Institute of the National Institutes of Health.