You may no longer be more likely to go into cardiac arrest on Monday morning, study says

(CNN)The most common time to experience sudden cardiac arrest could be changing, according to new research.

"The dogma -- in fact, this is everywhere, in all the textbooks about sudden cardiac arrest -- [is that] the most common time period for people to have a sudden cardiac arrest is early in the morning," said Dr. Sumeet Chugh, one of the authors of the study published in the journal Heart Rhythm.
    Chugh, Price Professor and associate director of the Heart Institute and director of the Heart Rhythm Center at Cedars-Sinai, and his co-authors used the Oregon Sudden Unexpected Death Study to look at 2,631 cases of sudden cardiac arrest.
      Of those incidences, the most commonly reported time was the afternoon, when 31.6% of cases happened. Only 13.9% happened in the early morning, 27.6% in the morning and 26.9% in the evening.
      The researchers looked at sudden cardiac arrest, an electrical malfunction in the heart, rather than heart attacks, which are blockages, with the understanding that both can happen at the same time.
      For Chugh, there were a few ways to explain this change in peak times. Among them is increased accuracy in observations of the timing of the events. Also, treatment is changing for people who experience or could be at risk for sudden cardiac arrest, and medications or other treatments could be affecting their peak times. Another factor may be the shift to a more 24/7 culture.
      "Our hypothesis is that in the last decade or two decades, we've really changed the way that we behave as human beings. We've changed the way that we work. We are constantly wired," Chugh said. "I would call it an 'always on' existence. A lot of people are working all the time, or they're tied to, or tethered to, a smartphone, almost every instant of the day, sometimes at night."
      Others have also considered the idea that new technology could play a part in potential changes in the most common times for cardiac arrest events.
      "Maybe because we are constantly working, connected, living in a 24/7 culture, that maybe that's part of the reason things are a little bit different now. Of course, we don't know that for sure. This is all observational," said Dr. Comilla Sasson, vice president of emergency cardiovascular care, science and innovation at the American Heart Association.
      Sasson, who was not involved in the new research, said its findings were not necessarily "surprising," as previous research has had similar results, such as a higher number of cardiac arrests during daytime hours. However, she suggests that this research could mean "we are getting better, hopefully, at capturing when a sudden cardiac arrest event is actually happening.
      "The lows are still the lows in terms of the timing, and I think for me, that's really the take-home point," she said "There is something to be said about our bodies' natural circadian rhythms, and I think this tells us that there is something that happens to our bodies overnight."
      Chugh's research also suggests that Monday may no longer be the most common day of the week for sudden cardiac arrest.