The news that former Vice President Dick Cheney suffered his fifth heart attack Monday and was admitted to a hospital, where apparently he is recovering nicely, naturally raises the question of how many heart attacks one person can have.
Five heart attacks may seem like a lot, but it really isn't, experts said. Physicians have become better at diagnosing very small heart attacks that might have passed by unobserved in the past, and improvements in therapy have made large, killer heart attacks less common.
The tests for troponins -- cardiac enzymes released from damaged heart muscle during a heart attack -- have become very sensitive and "can pick up a very small amount of heart damage," said Dr. Gregg Fonarow, a cardiologist at UCLA's Reagan Medical Center. "If the attacks are very small, there would not necessarily be any substantial impairment of heart function."
At the same time, improved treatments for heart disease mean that many heart attacks are smaller than they would have been a generation ago. Drugs to prevent clotting, reduce cholesterol, lower blood pressure and dissolve clots have reduced the likelihood of a massive attack in someone with diagnosed heart disease. "With aggressive medical therapy, we don't see the very big heart attacks we used to have 20 years ago," said Dr. Robert Kloner, a cardiologist at USC's Keck School of Medicine. "People can have small heart attacks multiple times and still do very well."
One factor that may be operating in Cheney's favor is that he has suffered heart problems since 1978. Over that time, "it is likely that he has developed collateral [new] blood vessels that grow into the areas not getting enough oxygen," Kloner said. "That might be something that is helping him."
So how many heart attacks can a person have and still survive? The answer depends on the amount of damage to the left ventricle, which pumps blood into the arteries. Problems arise when about 40% of the muscle in the ventricle becomes damaged. Then, a patient may die or require a heart transplant or other drastic measures. Cheney's physicians have not revealed any information about the condition of his ventricle.
Apparently, the Guinness World Records do not list the individual who has suffered the most heart attacks during his or her lifetime, and doctors don't seem to keep track of it either. But Fonarow said he has patients who have had eight or nine and are still going strong.
-- Thomas H. Maugh II
Photo: Former US Vice President Dick Cheney at the American Enterprise Institute for Public Policy Research on May 21, 2009. Credit: Michael Reynolds / EPA