Heart attacks occur when an artery blockage cuts off blood flow to the heart and cells in the affected portion of the heart begin to die. Commonly it is a constriction of the coronary artery by a blood clot (coronary thrombosis) that prevents the blood from reaching the heart. Chest pains, vomiting and cold sweats are the main symptoms.
A 1994 WHO study reported that globally the heart attack rate in men aged 35 to 64 years is 4 to 5 times higher than that for women. Still, there is considerable variation: Glasgow has the highest rate of female heart attacks of the 36 communities studied in 21 countries (260 per 100,000), and this exceeds the rate for southern European men. Finland has the highest rate of male heart attacks (910 per 100,000).
Each year, some 250,000 people in the US die unexpectedly from sudden cardiac death – a massive heart attack that arrives unheralded. Most of the time it occurs in older persons, usually those with coronary artery disease, or hardening of the arteries. A very small percentage of these cases occur in healthy young people. In those aged 25 to 35, premature coronary artery disease or congenital heart defects are a main cause of sudden cardiac death. In teens and children, congenital defects, such as an abnormal thickening of the heart wall, are often to blame. But in about one in twenty cases, the cause of sudden death remains a medical mystery. The heart looks perfectly normal on autopsy. It is suspected that gene defects will be uncovered in most, if not all, of those who succumb to unexplained sudden cardiac death. This includes many young athletes, children, and even babies with SIDS, or sudden infant death syndrome. It is estimated that anywhere from 1 in 3,000 to 1 in 5,000 Americans have some kind of genetic defect that may predispose them to heart rhythm problems and put them at risk of sudden death.
The US Centers for Disease Control (CDC) reported in 2001 that the rate of young people dying from cardiac arrest had soared. 3,000 young adults (age 15 to 34) died, a 10 percent increase over the previous decade. A few have unsuspected genetic conditions predisposing them to heart problems, but many of the deaths involved clogged arteries (atherosclerosis).