Aortic regurgitation is a heart condition where the aortic valve does not close properly, allowing blood to flow backward from the aorta into the left ventricle during diastole. This can lead to an increase in the volume of blood in the left ventricle, causing it to enlarge and work harder to pump blood effectively. Common causes of aortic regurgitation include rheumatic fever, bacterial endocarditis, and aortic dissection. Symptoms may include fatigue, shortness of breath, and palpitations. Diagnosis is typically made through a physical exam and imaging tests like an echocardiogram. Treatment options may involve medication or surgery, depending on severity.