best heart doctors in this area What are common heart conditions? Common heart conditions Coronary artery disease. Coronary artery disease (CAD), the most common heart disease, occurs when LDL, or "bad" cholesterol, builds up plaque in your heart's arteries. ... Heart failure. ... Arrhythmia. ... Valvular heart disease. ... Aortic aneurysms. ... Heart infections. ... Heart problems at birth. ... Related conditions.