Circadian Rhythms and Acute Coronary Syndrome in the Elderly

Ischemic heart disease is the leading cause of death in Western countries. The incidence, prevalence and mortality rate of acute cardiac events increase with age. Circadian rhythms allow organisms to prepare for their daily fluctuations brought on by day-night cycles, thus playing an important role in the cardiovascular physiology. This can be sometimes a double-edged sword, since exaggerated responses may not be beneficial or may be even harmful in individuals susceptible to adverse acute cardiovascular events. Remarkably, occurrence of such events has been related to a circadian pattern with a peak in the morning hours. Of interest, elderly patients seem to have an increased risk of acute coronary events, especially in the morning, though a bimodal distribution has also been observed. Further studies are required to get more insights on age-related differential circadian patterns in acute coronary syndromes patients.