The most accurate way to classify the human heart is as a four-chambered muscular organ composed of distinct anatomical regions (right and left atria, right and left ventricles, apex, and interventricular septum) with specialized cell types such as atrial and ventricular cardiomyocytes, fibroblasts, endothelial cells, pericytes, smooth muscle cells, immune cells, and others. The heart is classified based on its structure, cellular composition, and function within the cardiovascular system. It has three tissue layers—epicardium, myocardium, and endocardium—and its cellular heterogeneity and chamber-specific features define its role as a pump that moves blood through the body with distinct mechanical and physiological properties between its chambers.
This classification incorporates anatomical, cellular, and molecular levels for precision, highlighting the heart's chamber-specific regions and specialized cells that contribute to its diverse roles in circulation.