why heart attacks kill

Tuesday, July 13, 2010

My favorite team is anybody who plays the Yankees.

George Steinbrenner, the ship builder who also resurrected the New York Yankees empire died this morning of a heart attack. A myocardial infarction or heart attack doesn’t actually kill; the complications it causes are the killer.

The heart is a two stage electrical pump with heart muscle or myocaridium (myo=muscle + cardium=heart) being ordered to squeezing in a coordinated beat by an electrical signal that is automatically generated in atrium or collecting (upper) chamber of the heart. If heart muscle becomes irritated, short circuits in the electrical system can cause the ventricle or pumping (lower) chamber of the heart to malfunction. Sudden death may occur due to ventricular fibrillation where the heart fails to have a coordinated beat and sits there jiggling like a bowl of jello.

When a heart attack occurs, it is most often due to a clot that forms in one of the arteries that supplies heart muscle with blood. Without oxygen and nutrients, the muscle cells starve and start to ache causing chest pain or angina (sometimes it may be indigestion, arm and jaw ache or shortness of breath). If the clot is not treated, heart muscle starts to infarct or die. The amount of heart muscle at risk depends upon anatomy and what artery clots off. If it is a tiny branch artery, then just small amount of heart muscle is at risk; if it’s one of the three major arteries, then massive damage can occur. Unfortunately, the electrical system of the heart doesn’t particularly care if there is a small short circuit or a major power outage. Sudden death from a cardiac rhythm disturbance occurs because there is a focus of electrical irritability causing the ventricular fibrillation.

Size does matter in less common reasons to die of a heart attack. If a large amount of heart muscle is lost, the heart may be unable to generate enough squeeze to send blood to the rest of the body. No blood flow means no oxygen and no life. Large heart attacks can also cause the valves in the heart to malfunction, again disrupting blood flow to the body. And rarely, myocardial infarction cause also damaged muscle fibers to tear or rupture leading to sudden death.

The reason to understand the cause of death is to be able to do something about it. Getting emergency help for people suffering with chest pain is step one. The reason to call 911 instead of driving to the hospital is that ambulances carry monitors to look for abnormal heart rhythms and use medications to stabilize electrical activity and if necessary to use a defibrillator to treat sudden death. Step two is trying to re-establish blood supply to the area of the heart that is dying. In an acute myocardial infarction , where the EKG show a heart attack, the artery can be opened by emergency heart catheterization and angioplasty, perhaps with a stent, or the clot can be dissolved with drugs like TNK or TPA.

Step three really is step zero and that is prevention both as an individual and as a community. While one cannot control genetics and family history for heart disease, the goal is to decreasing risk by controlling blood pressure, high cholesterol and diabetes if they are present. Avoiding smoking is a given. And for community, it would be ideal if everybody could perform CPR and know how to use an AED (automatic external defibrillator) because even in the ideal world, people will still have heart attacks.

As with any celebrity who dies, the public will always be curious of the circumstances. But as it turns out, the final step in death is always the same. The heart stops beating and the lungs stop breathing. But for just today, perhaps my favorite team will wear the Yankee pinstripes.

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