Atsushi Sorita, M.D., a senior fellow in preventive medicine at Mayo Clinic, describes a study that found more people die and emergency hospital treatment takes longer for heart attack victims who arrive at the hospital during off-hours (nights and weekends), compared with people who arrive during regular daily hours. Mayo Clinic researchers analyzed results of 48 studies published between 2001 and 2013 involving 1.8 million people in the United States, Europe and Canada to assess the effect of off-hour hospital arrival for heart attack patients.