UCalgary lab discovers fundamental mechanism for regulating heart rate

The body’s ability to regulate heart rate is critical for cardiac performance and key to survival. For example, if your heart rate is too slow or can’t increase effectively during exercise, tissues and organs won’t receive the oxygen they need to function properly.

There are numerous mechanisms behind the body’s ability to regulate heart rate, but many are not well understood. Cumming School of Medicine professor Dr. Robert Rose, PhD, is working to change that.

His laboratory recently made a critical discovery in this area, identifying a previously unknown mechanism for heart rate regulation. The results are published in the journal Cardiovascular Research, a top journal in the field.

Connection between hormones and the heartbeat

The Rose lab discovered that hormones produced within the heart, called natriuretic peptides, communicate at the molecular level with a specific natriuretic peptide receptor in the sinoatrial node, the small, specialized region of the heart where the heartbeat originates, to maintain heart rate and sinoatrial node function.

While natriuretic peptides are known for their ability to control other aspects of cardiovascular function, these effects in the sinoatrial node were previously unknown. The study identifies an intricate cross-talk between signaling pathways that regulate ion channel function in these specialized cells.

It’s an exciting find for Rose.

“This study shows that the heart uses the hormones right where they are made to help maintain its function,” he says. “It identifies a previously unknown way that these hormones work with their receptors to regulate electrical function in the heart.”

Study has important clinical implications

The sinoatrial node was discovered more than 100 years ago, yet in many ways it is a very mysterious region of the heart. Scientists still have much to learn about its function and regulation, because of its small size. Studying this region of the heart requires special equipment and expertise.

Yet understanding how the sinoatrial node functions is critical, as dysfunction in this area has an enormous impact on individuals. People with sinoatrial node dysfunction may suffer from dizziness, fatigue, syncope, poor exercise and stress tolerance, and sudden death.

“This finding has implications for potential treatments for sinoatrial node dysfunction,” says Rose, noting the lab is now investigating the mechanisms identified in this new study in individuals with pathologies in the heart. “It essentially holds the key to the body’s ability to properly control heart rate.”

Dr. Paul Fedak, MD, PhD, director of the Libin Cardiovascular Institute, says Rose’s finding has important clinical implications.

“By leveraging these pathways, we could develop new treatments for many heart electrical disorders that could improve the quality of life for many people around the world,” says Fedak. “The Libin Institute is proud to support world-class basic and translational scientists like Professor Rose, and we are excited at the possibilities for our basic and translational scientists working with our clinicians to bring new therapies to our community."

This project was funded by the Canadian Institutes for Health Research.