Backup pacemakers? Study finds two mechanisms to support the sinoatrial node

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A new study identifies two backup mechanisms that support the sinoatrial node (SAN) in its tireless task of efficiently keeping the heart beating even under adverse circumstances and in the face of arrhythmias.

Prior to this research from Ohio State University (OSU), the specific mechanisms that have supported the SAN in maintaining robustness, that is preventing the failure of the heart to function, have been unknown.

The study was published on July 26 in Science Translational Medicine.

Reaching a full understanding of the SAN’s ability to keep functioning has been difficult because the human SAN differs greatly from animal models and clinical electrode recordings provide insufficient information, explained author Vadim Fedorov, an associate professor in OSU’s department of physiology and cell biology.

The research team overcame these challenges by applying several different techniques including 3D tissue reconstruction and molecular characterization to 21 donated human hearts.

Ultimately, they discovered that the SAN has one backup pacemaker mechanism in its “head” region and a second backup in its “tail” region. These two additional pacemakers proved less sensitive to chemical changes that can disable the highly sensitive, central pacemaker of the SAN.

The findings hold out promise for new and better treatments for arrhythmias.

“Robustness—through functional, structural, and molecular redundancies—is an important property of the human SAN, which allows it to efficiently maintain its automaticity and conduction even during… perturbations,” the authors wrote in the study.

They added that in-depth knowledge of the entire SAN complex during both normal and pathologic circumstance can serve as the basis for the development of novel treatments for SAN arrhythmias.