[MUSIC PLAYING] Over 300,000 Americans die every year from sudden cardiac arrest. And many of those could be prevented. So it's very common for people to confuse sudden cardiac arrest and heart attacks. Heart attacks occur when there's a blockage in one of the coronary arteries. So there's obstructed blood flow to the heart. However, sudden cardiac arrest is basically when the patient's heart stops. And the most common cause of that is these chaotic rhythms that we call ventricular tachycardia or ventricular fibrillation. One of the most important features that we use to determine whether a patient is at risk for sudden cardiac arrest is what is known as the ejection fraction. And the ejection fraction is a measure of the strength of the left ventricle of the heart. A normal ejection fraction is 55% to 60%. And when patients get down to an ejection fraction of 35%, either because they've had heart attacks or they have some other form of cardiomyopathy, we start to get worried that they are at risk for sudden cardiac arrest. Measuring the ejection fraction is very easy. It can be obtained from an echocardiogram, a stress test, a heart catheterization, or an MRI. The most important thing is following up with their doctors and taking their medications appropriately. Some patients actually qualify for, what we call, implantable cardioverter defibrillators as well. We also call them ICD's or defibrillators. And those are implantable devices that monitor the heart rhythm all the time. The University of Virginia is very fortunate to have an outstanding device program. We have a wonderful device clinic that operates five days a week and is staffed by device nurses, almost all of whom are certified by the heart rhythm society as being experts in device management and programming. We have a large team of doctors who are all expert in implanting these devices, and also following them over time. [MUSIC PLAYING]