Genetics, stress, diet, and lack of physical activity can cause cardiovascular disease. Common diagnostic tests include cardiac CT scans, halter monitors, Doppler ultrasounds, and electrocardiograms. CT scans provide detailed 3D images of the heart and are used to detect calcium buildup or problems with the heart, valves, or aorta. Halter monitors continuously monitor heart activity for at least 24 hours to detect arrhythmias or epileptic events. Doppler ultrasounds use sound waves to measure blood flow and pressure and diagnose issues like blood clots, heart defects, narrowed or blocked arteries, or valve problems. These tests can often be done as outpatients without overnight hospital stays.