What are the Consequences of a Heart Attack?
November 20, 2008 by rainier
When a portion of heart muscle dies, several bad things can happen. If the amount of damage is large enough, the patient can develop immediate heart failure and shock. (When doctors refer to “shock,” they are talking about extremely low blood pressure, caused by the heart’s inability to pump sufficient blood to the body’s tissues.) When heart failure occurs immediately after a heart attack, there is an extremely high risk of early death.
If the amount of heart damage is only mild or moderate, heart failure does not occur – at least, not right away. However, in the effort to heal itself, the heart goes through a period of “remodeling,” in which the heart enlarges and changes shape. This remodeling eventually leads to a decrease in cardiac pumping efficiency, and can lead to a more gradual onset of heart failure months or years after the heart attack. To a large degree, the outcome of a heart attack depends on the amount of heart muscle that dies. This, in turn, is related to which coronary artery is blocked (click here for a description of the coronary arteries), and to where in the artery the blockage occurs. (A blockage near the origin of an artery will affect more heart muscle than a blockage farther down the artery.)
During the first few hours of an acute heart attack, a transient form of electrical instability occurs that makes the heart prone to develop ventricular tachycardia and ventricular fibrillation – frequently lethal heart arrhythmias. Furthermore, during the healing process, the scar tissue that replaces the dead heart muscle can cause a permanent electrical instability. Thus, sudden death is common both during acute heart attacks and among survivors of heart attacks, and accounts for approximately 50% of all deaths due to coronary artery disease.
