Sudden Cardiac Death in a young person is a tragic and devastating event.  There are about 3,000 such deaths in the US every year, most of which are due to SIDS (sudden infant death syndrome).  The incidence of SIDS decreased with the recognition that we need to put infants to sleep on their backs ("Back to Sleep"), but infants still die at about the same rate now as they did 10 years ago for various reasons, including maternal smoking and genetic factors.  For older children, the five most common causes of sudden cardiac death are hypertrophic cardiomyopathy, commotio cordis, coronary artery anomalies, myocarditis, and a ruptured aortic aneurysm from Marfan syndrome.

 Hypertrophic cardiomyopathy is a genetic disorder that affects the heart muscle.  It is often inherited from a parents who may or may not know they have it.  Commotio cordis occurs when an object, such as a baseball or lacrosse stick, strikes the chest at the exact speed and exact time to cause a deadly heart rhythm.  Coronary arteries are the tiny blood vessels that bring oxygen-rich blood to the heart muscle itself.  Some people are born with abnormal coronary anatomy such that blood flow to the heart muscle is decreased, a situation that can get worse when the heart needs more blood during exercise.  A heart starved for oxygen can start a deadly heart rhythm.  Myocarditis is an infection of the heart muscle that can make its squeezing very weak, and can be another cause of a deadly abnormal rhythm.  Given that an abnormal rhythm, ie ventricular fibrillation, is the end result of many of these diseases, you can understand why defibrillators are so important in preventing Sudden Cardiac Arrest from becoming Sudden Cardiac Death.  Defibrillators are the machines you see doctors using on TV shows when someone is dying in the emergency department- they grab the paddles, squeeze them to the patient's chest, deliver a shock, and then the patient jumps off the bed, hopefully with a normal heart rhythm.  It's not quite so dramatic in real life, but it is pretty awesome when it works.  Automated External Defibrillators (AEDs) are now available in many public places and at sporting events.  

What can you do to prevent Sudden Cardiac Death?  If you have an infant at home, put the baby to sleep on its back; if you smoke, stop.  For athletes, learn your family history- does anyone have hypertrophic cardiomyopathy?  Has anyone ever died suddenly?  Does anyone have Marfan syndrome? And pay attention to your symptoms- do you have chest pain with exercise?  Have you fainted with exercise?  If so, you might need to get checked out by your doctor.  And for parents, learn CPR and how to use an AED; you might save a life.

Andrew Hoyer, M.D.