Best time to have a heart attack?

There is no opportune time to have a heart attack. However, according to a new study, some times may be better than others.

Results from a Mayo Clinic study published in late January in the British Medical Journal reveal that deaths occur more often and emergency hospital treatment takes longer for those suffering heart attacks who arrive at the hospital during nights and weekends than for those patients who arrive during regular daily hours.

Additionally, the study found that patients who arrived at the hospital during off-hours are 5 percent more likely to die—both while in the hospital and 30 days after discharge—than those patients who arrived at the hospital during regular hours. This resulted in an extra 4,000 U.S. deaths annually alone.

Mayo Clinic researchers analyzed results of 48 studies published between 2001 and 2013 involving 1.8 million U.S. patients in the United States, Canada and Europe to assess the effect of off-hour hospital arrivals for heart attack patients.

Researchers also analyzed patients who had a specific type of heart attack called an ST-elevation myocardial infarction or STEMI. Dr. Henry Ting, Mayo Clinic cardiologist and senior study author said in a statement that STEMIs are considered the most severe heart attack and require immediate care.

For patients who arrived during off-hours, study results showed a delay of almost 15 minutes in “door-to-balloon time,” the time from hospital arrival until the patient’s blocked artery is opened. Dr. Ting said that the delay in treating STEMIs could increase the likelihood of death by as much as 10 to 15 percent.

Although the review found a connection between off-hours arrival at a hospital and a greater risk of death, it did not establish a cause-and-effect relationship.

Researchers found that additional studies would be needed to account for differences in levels of care during regular and off-hours, including number of staff and their level of expertise.

The study authors caution people who develop signs of a heart attack, such as chest pain or shortness of breath to call 911 immediately, regardless of time of day or day of the week. The difference in risk of death between off-hours and regular hours does not warrant waiting in any circumstances, said Dr. Atsushi Sorita, lead author of the study.