Heart Attack Severity Dependent On Time Of Day?

A 2011 study published in the academic journal “Circulation Research” found a strong link between the severity of a heart attack and the time of its occurrence. A detailed analysis of more than 1,000 heart-attack sufferers showed a peak in damage caused by heart attacks that occur between 1 a.m. and 5 a.m., with 82 percent greater damage caused than the time of day with the lowest injury. Researchers at the Minneapolis Heart Institute at Abbott Northwestern Hospital believe this finding could be used to help prevent heart attack onset.

This human analysis study was based upon previous research that involved rodent study. Researchers hoped to determine whether the time of day when a heart attack occurs influences the severity of the injury caused to the heart. Before determining a strong link between heart damage and the time of day of the heart attack in humans, researchers were unsure if the link existed only in rodents.

The importance of the study’s findings is potentially significant for preventative cardiac medicine. Researchers explained that the heart is not always equally able to defend itself. As the rest of the human body operates on a 24-hour cycle, so does the heart. If a heart attack occurs during one of the most vulnerable times in the heart’s 24-hour cycle, the damage will be much more severe and the heart will not be able to defend itself optimally. Researchers are still learning to identify the protective changes that occur in the peak and low points of the heart’s cycle.

The potential pharmaceutical implications of this study are many. Pharmaceutical manufacturers hoping to develop cardioprotective drugs could benefit heavily from a better of how the heart protects itself and when it needs protection the most. However, a 2014 study by Mayo Clinic researchers suggests that there may be more at play. The study found that death rates for heart attack patients are higher and emergency treatment is slower when patients seek care at night or on weekends.

While the heart itself may be more vulnerable at certain times, the Mayo Clinic study suggests that the time of day patients seek care is also relevant to the survivability of a heart attack. The heart attacks themselves may not be any more severe at night than those during the day, but patients are still at a higher risk of fatality when seeking care during hours when hospitals have fewer staff and resources. In light of the 2011 study, which shows that heart attacks that occur in the middle of the night are more likely to be fatal, the Mayo Clinic study demonstrates the need for hospitals to operate on a 24-hour basis.