What is a heart attack?
The technical term for a heart attack is a myocardial infarction. Fortunately heart attacks in children are exceedingly rare. In adults, a myocardial infarction is typically caused by inadequate blood flow to the heart muscle. This is usually a result of atherosclerosis, or plaque build-up in the coronary arteries, the arteries that feed the heart muscle with blood. Plaque build-up results from risk factors such as high cholesterol, high blood pressure, diabetes, smoking, obesity, and genetic factors. When plaque build-up become severe, the artery becomes partially blocked. If a partially blocked artery becomes completely occluded by a blood clot, a myocardial infarction or heart attack results.
Although the process of atherosclerosis starts at a microscopic level during childhood and the teenage years, it typically does not cause enough plaque buildup to create any true blockage in the coronary arteries at this age. For this reason, myocardial infarctions due to plaque build-up in children are extremely rare.
What causes heart attacks in children?
Heart attacks in children, or true myocardial infarctions, do occasionally occur. The most common cause is a congenital abnormality of the coronary artery called ALCAPA. This stands for an anomalous left coronary artery from the pulmonary artery. The normal coronary arteries include a left and right coronary artery, both originating from the base of the aorta. With ALCAPA, the left coronary artery originates instead from the base of the pulmonary artery. A combination of low oxygen blood and decreased perfusion pressure results in inadequate blood and oxygen delivery to the heart muscle. This then causes a myocardial infarction, or heart attack. Babies with this problem typically require surgery to reimplant the left coronary artery to its normal location. Fortunately many babies with this problem are able to make a full recovery.
A second cause of heart attacks in children involves an anomalous origin of the coronary artery. Some children are born with a coronary artery originating from the incorrect sinus. The left coronary artery may originate from the right sinus of Valsalva, or the right coronary artery may originate from the left sinus of Valsalva. As the coronary artery travels between the aorta and pulmonary artery, it may become compressed or take off at an acute angle. During exercise, this may result in inadequate delivery of blood and oxygen to the heart muscle and a subsequent myocardial infarction, or heart attack.
In teenagers, a heart attack can occasionally occur because of coronary artery vasospasm. This is most often triggered by drug use or smoking. With coronary artery vasospasm, the coronary artery squeezes down and insufficient blood gets through. In addition, a blood clot may be formed at the location where the coronary artery squeezes down.
Can other problems be confused with heart attacks in children?
Many people may use the term heart attack to refer to any sudden heart event, including an arrhythmia or an episode of cardiac syncope. Although these episodes are not true myocardial infarctions, they can result in sudden cardiac death. Problems such as hypertrophic cardiomyopathy, ventricular tachycardia, long QT syndrome, myocarditis, and Marfan syndrome may all predispose a child or teenager to sudden cardiac events. Although these types of problems can be devastating when they occur in children, fortunately they are not heart attacks in the literal sense of the word.
In summary, heart attacks in children are rare. Unfortunately, when they do occur they can be potentially life-threatening.