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No one can plan a heart attack, but when they occur on nights and weekends, patients are more likely to die, a new study confirms. Dan Steinberg / AP

A heart attack is more likely to kill you if it happens on the weekend or at night, a new study shows.

It’s not that off-hours attacks are more deadly — it’s that hospital care may not be as timely, researchers reported Tuesday in the British Medical Journal online.

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"We all know that hospitals have fewer staff and resources at night," said the study’s lead author Dr. Atsushi Sorita, a senior fellow in preventive medicine at the Mayo Clinic Rochester.

“Patients do not get to choose when they have a heart attack,” Sorita said. “I believe the health system should be designed so that it provides consistent care 24 hours a day, 7 days a week.”

Sorita and his colleagues scrutinized data from 48 studies in a meta-analysis, which included nearly 1.9 million heart attack patients. The studies they examined were from the United States, Canada and Europe.

The researchers found that patients who showed up at the hospital during off hours were 5 percent more likely to die within 30 days of the heart attack than those who showed up during regular hours.

While 5 percent may not sound like a big number, the researchers calculated that it could translate into 3,800 preventable deaths each year.

Another finding: Once patients arrived at the hospital it took 15 minutes longer during off hours to receive artery-clearing balloon angioplasty.

There might be other explanations for the higher death rate, such as patients taking longer to get to the hospital on nights and weekends, but “the delay in door-to-balloon time is disturbing,” said Dr. Joon Lee, chief of cardiology at the University of Pittsburgh Medical Center.

“Hospitals need to ensure systems, staffing and protocols are in place to ensure timely, consistent, high quality care for acute myocardial infarction 24 hours a day and 7 days a week,” said Dr. Gregg Fonarow, co-director of the preventive cardiology program at UCLA.

Even more lives might be saved, Lee said, if people headed for the hospital at the first symptoms “instead of waiting an hour trying to decide if it’s a heart attack.”