It seems wrong to say that some people are more deserving of heart attacks than others, but when a person with a propensity for smoking and eating slingers and a lack of interest in exercise suffers a coronary, let's just say no one is very much surprised.
But what about when a person who eat lots of fish and whole grains and religiously goes for a run every morning suddenly starts getting pains in the ticker? Then you'd probably say it came out of nowhere. But did it?
"These are people we do not expect to die of cardiac causes," Phyllis K. Stein, a professor and director of Washington University's Heart Rate Variability Laboratory, said in a press release. "They appear healthy, but they're not. We have shown a way they're not healthy that isn't showing up using standard tests."
It's not uncommon for a heart to suddenly start beating out of rhythm. The researchers call a ventricular premature beat,or VPB, and it happens when the body, for some reason, sends a signal for the heart to beat before it's supposed to.
During a VPB, the heart contracts before the ventricle has finished filling with blood and sends out less blood to the rest of the body. On the second beat, the heart's rhythm returns to normal, so there's more blood in the ventricle, which means the heart sends out extra blood.
A healthy heart will speed up or slow down to compensate for the different amounts of blood. A heart that can't adjust the rate of its beating has a condition called abnormal heart rate turbulence, and its an early sign of trouble. Which means that now you've got another thing to worry about.
Over the course of four years, from 1989 and 1993, Stein and her colleagues observed the heart rate turbulence in 1,300 patients using a device called a Holter monitor that records the electrical signals emanating from the heart. Subsequently, the team observed those patients for another twelve years.
The patients were divided into three groups: "clinical" which had a history of cardiovascular problems, "subclinical" which had risk factors like high blood pressure and diabetes but no actual problems and "healthy." There were patients with abnormal heart turbulence in all three groups, but the condition's effects were most obvious in the "healthy" group.
During the second half of the study, the 21 patients in the "healthy" group with abnormal heart turbulence died off at a much higher rate that the patients in the "subclinical" group with good heart turbulence. Compared to the other 336 "healthy" patients, they were eight times more likely to die.
"Even though it's a small group of people, they're actually at very high risk," Stein said. "They're actually not healthy. Something is wrong. But the conventional risk factors don't pick it up."
The study was published this week in the Journal of Cardiovascular Electrophysiology.
