Daytime Heart Attack Victims Fare Better

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TUESDAY, June 17, 2003 (HealthDayNews) -- If you have a heart attack late at night and receive an angioplasty, your odds of a successful recovery are substantially reduced compared with those who have a heart attack during the day.

According to the results of a new study, heart attack patients "showed a difference in outcome depending on whether they were treated during the day or during the night," says Dr. Felix Zijlstra, a cardiologist at Weezenlanden Hospital in Zwolle, the Netherlands.

Zijlstra and his colleagues found patients treated during off-hours, 6 p.m. to 8 a.m., had increased mortality within 30 days. Of the 1,702 patients studied, about 2 percent of those treated during the day had died within 30 days after their heart attack, compared with more than 4 percent of those treated during the night.

When the researchers looked at the success rates of angioplasties, the procedure used to open blocked coronary arteries, they found the procedure failed in about 4 percent of patients treated during the day compared with about 7 percent of patients treated at night. The study appears in the June 18 issue of the Journal of the American College of Cardiology.

Zijlstra speculates this difference is due to the variations in our body clock, known as circadian rhythms. "There is evidence that everything in our body is related to circadian patterns," Zijlstra says. Neural hormonal shifts during the day may affect how well blood flow to the coronary artery is restored during angioplasty, he adds.

However, there is an argument as to whether the difference in outcome is due to the patient or the doctor, Zijlstra notes. In their study, all the doctors who performed angioplasties were senior cardiologists with many years of experience. And all patients were treated within the same time from the onset of their heart attack.

"We can never exclude the possibility that a sleepy cardiologist may make a wrong decision, but it is not very likely," Zijlstra says.

He adds that "it is important to be aware that patients treated during off-hours may have worse outcomes." These patients may need additional stabilizing medications or additional blood-thinning medications, Zijlstra says.

Drs. Frederick A. Spencer and Richard C. Becker from the University of Massachusetts Medical School, the authors of an accompanying editorial, do not completely agree that a biological basis accounts for the differences in outcomes.

Spencer, an associate professor of medicine, believes the differences are more a function of the health-care system itself. "The system clearly has differences day to night that have not been well explored," he says. A physician who is performing angioplasties round the clock simply is not as good at 3 a.m., he adds.

There should be day and night teams and required rest periods for doctors performing angioplasties, he says. "Physicians are people, too, and we have to pay attention to sleep deprivation. But if we want to optimize health care it's not going to come cheap."

More information

The National Heart, Lung, and Blood Institute has information on both surviving and preventing heart attacks.