Wednesday, July 1, 2009
Michael Jackson Dies of Cardiac arrest
What is the difference between cardiac arrest and heart attack?
Christie Ballantyne, interim chief of cardiology at Baylor College of Medicine in Houston, Tex., tells Scientific American that cardiac arrest just means that someone has lost their blood pressure and their pulse. "Usually, this means there has been a collapse of the circulatory systems and many times, it is due to an [accelerated] heartbeat," he says. When the heart is contracting so quickly, blood can no longer be squeezed from the pumping chamber and circulate to the brain, leading to death within minutes.
This accelerated heartbeat, or arrhythmia, can be a sign of a heart attack, which stems from buildup of plaque in the arteries. But not all heart attacks lead to cardiac arrest, and they are not the only cause of cardiac arrests, Ballantyne says. Cardiac arrest can occur from a major blood clot in the lung or a heart enlarged from infection or other damage. Previous heart attacks can also leave scars that injure the heart's pacemaking electrical system.