Heart attacks remain the number one cause of death in the United States. Each year, about 1.1 million Americans suffer a heart attack, and 460,000 of them die.
A heart attack — also called a myocardial infarction (MI) — occurs when a blood clot forms in a coronary artery, blocking blood flow to the heart.
Today, heart attack patients are usually treated with clot-dissolving drugs or undergo an emergency stenting procedure to re-establish the blood flow to the heart quickly. This must be done to minimize damage to the heart muscle. The good news is that if you reach the hospital alive, you’ll have better than a 90 percent chance of surviving.
If a heart attack damages your heart, there is also a danger of developing serious complications such as congestive heart failure or an arrhythmia that could cause sudden death.
For this reason, heart attack survivors undergo a battery of tests, including an echocardiogram, which employs sound waves over the chest wall to evaluate the heart’s function, and provides the all-important number known as the “ejection fraction.”
The ejection fraction is the measurement that tells the doctor whether your heart is still able to pump normally, or if it has been damaged — creating a risk of developing serious post-heart attack complications.
Normally, the heart pumps a little more than half the blood’s volume out with each beat. A doctor is hoping to see an ejection fraction of 55 to 70 percent (representing the ratio of the blood in the left ventricle that moves with each heartbeat.) An ejection fraction below 55 percent indicates that the heart is weakened, and 40 percent confirms a diagnosis of congestive heart failure.
If the ejection fraction is lower than 35 percent, the patient is in danger of suffering a life- threatening irregular heartbeat that could cause sudden cardiac death.