Several studies have shown that the incidence of myocardial infarction (MI) does not follow a continuous pattern throughout the week, and that there is an increase in mortality on Mondays and possibly a decrease on Thursdays.1 The reasons for such a pattern are not well understood, and several hypothesis have been made, namely a change from leisurely weekend activities to stressful work among working patients1 or a Monday increase in the incidence of life threatening ventricular arrhythmias.2 To our knowledge, no assessment of the weekly distribution of MI mortality has been performed in France. Thus, we used the data from the French national mortality statistics and from the French MONICA (monitoring trends and determinants in coronary disease) registers to assess the weekly pattern of incidence and mortality from MI.

Mortality data for coronary heart disease (ICD codes 410–414) was obtained from the French National Mortality Statistics (INSERM SC8, …