What defines coronary artery disease (CAD)?

Coronary artery disease (CAD) is primarily characterized by the buildup of plaque within the coronary arteries, which supply blood to the heart muscle. This accumulation narrows the arteries, limiting blood flow and potentially leading to ischemic heart conditions, such as angina or myocardial infarction (heart attack). The plaque comprises cholesterol, fatty substances, cellular waste products, and calcium, which can harden and significantly impair the function of the arteries over time.

The other options refer to different cardiovascular conditions. A heart rhythm disorder involves irregularities in the heart's electrical conduction system, affecting heartbeat timing and rhythm but not directly related to arterial blockages. Heart valve disease concerns issues with any of the four heart valves, impacting blood flow but is not characterized by plaque buildup in arteries. A defect present at birth, known as congenital heart disease, involves structural problems in the heart and its major blood vessels, which can affect heart function but not specifically related to CAD. Therefore, the correct answer accurately encapsulates the defining feature of coronary artery disease.