Acute ischemic events occur most frequently at dawn and in the early hours of the morning. The development of these severe clinical events exhibits a temporal relationship with changes in various hemodynamic, prothrombotic, and hormonal processes. The authors highlight not only these relationships but also the potential protective effect of increased bradykinin levels and the inhibition of different angiotensin II (AT-II) receptors (AT2, AT4) against unfavorable prothrombotic influences, which-based on studies to date-decreases the risk of acute cardiovascular events. Comparisons are presented between the different effects of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers on factors that influence thrombus formation and myocardial infarction risk.