More than 75,000 new cases of a type of heart arrhythmia called sinus node dysfunction (also referred to as sick sinus syndrome) are diagnosed each year in the United States. That number is projected to double by the year 2060.

The condition involves malfunction of the heart's natural pacemaker. Some patients are asymptomatic, while others experience symptoms ranging from fatigue to fainting or chest pain. Surgical implantation of a pacemaker device is presently the most efficient treatment.

New research led by Alexey Glukhov, PhD, assistant professor, Cardiovascular Medicine, will focus on determining whether a heart protein called caveolin-3 is involved in sinus node dysfunction.

His research team hopes the work will lead to identifying better treatment options. "This study will allow us to design more effective therapeutic approaches aimed at preventing the degradation or promoting the restoration of cardiac cytoarchitecture," wrote Dr. Glukhov.

The National Institutes of Health - National Heart, Lung, and Blood Institute (NIH-NHLBI) awarded $1.9 M over 5 years for the study, which is entitled "Functional Microdomains in the Heart's Pacemaker: A New Dimension of Cardiac Remodeling."

Caveolins are proteins that form the structure of caveolae, which are pinched-in regions of cell membranes. Caveolin-3 is found in the membrane of muscle cells, including heart muscle cells (cardiomyocytes). Previous research by Dr. Glukhov and others suggests that natural pacemaking activity in the heart involves the caveolae of cardiomyocytes, and the Glukhov laboratory hypothesizes that caveolin-3 organizes signaling complexes required to maintain a steady heartbeat.

"We want to ascertain if caveolin-3 is a crucial protein involved in sinoatrial node dysfunction, and understand its potential as a target to restore sinoatrial node functioning in heart disease," wrote Dr. Glukhov.

Resources:

• "Functional Microdomains in the Heart's Pacemaker: A New Dimension of Cardiac Remodeling," NIH Granteome

Photo caption: A display panel with examples of cardiac pacemaker devices is used during a Mini Med School community lecture on heart arrhythmias in September, 2017. Photo credit: Clint Thayer/Department of Medicine