Myocardial infarction: time of day symptoms begin in adult females and adult males

The purpose of the study was to determine if there were differences in the time of day myocardial infarctions (MI) occur between adult females and males and if there were differences among genders in time of presentation for treatment. A two group, non-experimental chart review was conducted. Two hundred seventy-three randomly selected patient charts with a discharge diagnosis of acute MI were included, 109 females and 164 male charts. The raw data for time were converted to categorical variables: 00:00 to 06:00 "night"; 06:01 to 12:00 "morning"; 12:01 to 18:00 "afternoon"; and 18:01-23:59 "evening". Three research questions were investigated. First, what time of day do females experience MIs as opposed to males? Of 109 females, 26% (n=28) had MI symptoms begin at night; 30% (n=33) morning; 29% afternoon (n=32); and 15% (n=16) evening. In comparison, of 164 males, 27% (n=44) had MIs at night; 30% morning ( n=49); 32% afternoon (n=52); and 12% evening ( n=19). The research question addressed whether or not there was a difference between the time that MI related symptoms begin in adult females and males with a discharge diagnosis of acute myocardial infarction? There was not a statistical difference between females and males and the time of day MI related symptoms began (χ2 (3) = .642, p=.887). Third, was there a difference between time of symptom onset of myocardial infarctions and time of presentation for medical treatment among females and males? Ninety-nine females and 154 females were included to analyze this question. The sample is slightly smaller than the overall sample due to some patients having their MIs after admission to the hospital. The mean time of presentation for medical treatment after symptom onset for females was 327 minutes (SD=270) or 5 hours and 27 minutes. In comparison, males presented for medical treatment on an average of 330 minutes ( SD=407) or 5 hours and 30 minutes. The independent samples t-test results indicated that the differences were not statistically significant (t(251)=-.053, p=.958). In conclusion, the majority of patients, whether female or male, had MIs in the morning and afternoon and presented for treatment in similar time frames.