Heart Attack – What is it?

Heart attack, in the medical community, is known as a myocardial infarction (MI).  It occurs because one or more of the coronary arteries, that provide blood supply and oxygen to the heart muscle, are completely blocked off.  As a result, blood cannot get through the artery and part of the heart muscle does not get oxygen.  This can result in death of the heart muscle.

There are three main causes of heart attack that I will explain next:

1. Coronary Artery Disease – The coronary arteries that supply the blood to the heart (see picture) become narrowed by atherosclerosis.  Atherosclerosis involves a build-up of plaque inside the artery walls, also causing the arteries to harden and lose their elasticity.  If there is enough build-up of plaque in one or more of the coronary arteries, it can completely block off the blood supply to the heart.
2. Blood Clot – As plaque develops in the coronary arteries, it is subjected to the pressure of blood flowing through the narrowed arteries.  If some plaque breaks off at a particular site in a blood vessel of the heart, the body’s response is to heal that area so it forms a blood clot.  The blood clot that the body forms in the artery, however, can end up blocking off the coronary artery.
3. Spasm or Tightening of Coronary Artery – When the artery spasms, it results in blood and oxygen being unable to get to part of the heart that is supplied by that coronary artery.  There is often no reason for a coronary spasm, but it can be seen in people who use drugs such as cocaine, during times of psychological stress or cold temperatures.

Now that you understand what a heart attack (myocardial infarction) is, you will want to be able to identify the signs of  a heart attack.  Please stay tuned to future posts….