Cardiomyocytes: Structure, Function, and Emerging Insights in Heart Health and Disease

Cardiomyocytes, the contractile cells of the heart, are highly specialized muscle cells responsible for generating the rhythmic contractions that maintain blood circulation throughout the body. Unlike skeletal muscle fibers, cardiomyocytes are typically mononucleated, branched, and interconnected through intercalated discs containing gap junctions and desmosomes, which enable synchronized electrical and mechanical activity. They are rich in mitochondria to meet the high energy demands of continuous contraction and rely heavily on tightly regulated calcium signaling for excitation–contraction coupling. Although traditionally considered terminally differentiated with limited regenerative capacity, recent research highlights a modest ability for cardiomyocyte turnover and proliferation under specific conditions, offering potential avenues for regenerative therapies in cardiovascular disease. Their structural and functional integrity is central to cardiac physiology, and disturbances in cardiomyocyte homeostasis are key drivers of pathologies such as hypertrophy, heart failure, and arrhythmias.