Enron founder Ken Lay died unexpectedly of a heart attack Wednesday morning, seven weeks after he was convicted on several counts of conspiracy and fraud. "His heart simply gave out," said the pastor of Lay's church. Could stress have caused his death?
Absolutely. The release of stress hormones (like adrenalin) into the bloodstream increases the likelihood of both heart attack and sudden cardiac arrest. Studies of heart attack patients found that 15 percent to 30 percent of those admitted to a medical center had suffered from severe emotional stress. In another series of studies, doctors used data from implanted defibrillators to show that heart arrhythmias became more common across the country in the aftermath of 9/11.
Stress can cause heart problems in several different ways. First, an excess of stress hormones can cause a "myocardial infarction," otherwise known as a heart attack. A myocardial infarction occurs when a blockage forms in one of the arteries that supplies oxygenated blood to the heart muscle. Severe stress causes the heart to beat more quickly and increases blood flow through vessels that may already be narrowed by arterial plaques. This makes the plaques more likely to rupture, which can in turn cause a blood clot and the ensuing heart attack. (Stress hormones may also act directly on the plaques.)
High levels of stress hormone can also knock the heartbeat out of its natural rhythm. This happens most often when the heart lapses into "ventricular fibrillation" and its bottom chambers start beating at a very high speed. Blood stops circulating to the brain and death follows within 10 minutes. (If doctors reach a patient in time, they can try to save him with the electrical zap of a defibrillator.)
Stress can even produce the symptoms of a heart attack without causing any permanent damage to the heart muscle. A surplus of hormones will temporarily weaken the heart muscle cells of even very healthy people.
Bonus Explainer: News reports have indicated that Lay suffered a "massive heart attack." What's that?
It's just like a regular heart attack, but it affects more of the organ. Physicians might use the phrase "massive heart attack" to describe a myocardial infarction that destroys a large amount of tissue—say, more than 25 percent of the total heart muscle.
Ken Lay may not have died from a "massive heart attack" at all. Reporters often describe sudden-death scenarios as "massive heart attacks" even when there's little evidence that a heart attack has occurred. Lay's quick and unexpected demise was more likely the result of sudden cardiac arrest. A "massive heart attack" won't necessarily kill you—the phrase refers only to the destruction of heart muscle, not to the stoppage of the heart. (On the other hand, a heart attack that happens to get you in a sensitive spot can cause sudden cardiac arrest.)
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Explainer thanks Ilan Wittstein of Johns Hopkins Medicine and Douglas Zipes of the Indiana University School of Medicine.