Understanding heart disease requires a basic knowledge of the heart’s anatomy and physiology. The heart is a muscular structure whose function is comprised of two components that work together: the electrical and mechanical systems. The electrical system regulates heart rate and rhythm and involves important structures like the sinoatrial node, atrioventricular node, and His-Purkinje system. Mechanically, the heart pumps out blood with each contraction to the rest of the body in a rhythmic pattern. Deoxygenated blood enters the right side of the heart and is pumped into the lungs for oxygenation before being pumped out of the left side of the heart to the rest of the body. Issues in the electrical and/or mechanical components of the heart can lead to diseases that may require medications, implantable cardiac devices, or other interventions.