Primary angioplasty and diurnal variations.

Rev Esp Cardiol. 2009;62(6):704-12 709 rhythmic variations.2 It has been clearly demonstrated that the beginning of an acute myocardial infarction most frequently occurs in the early hours of the morning, which has raised our interest in finding out what causes explain this circadian pattern, and what their clinical and therapeutic implications are.2 Secondly, various studies have provided data regarding the poor clinical results obtained by primary PCI performed outside normal working hours (between 17:00 and 8:00).3,4 In particular, Henriques et al3 demonstrated that a total of 1702 patients with STEMI who came to the hospital between 18:00 y and 8:00 had a higher mortality index and a greater rate of primary PCI failure. Furthermore, in a cohort study of 102 086 patients from the National Registry of Myocardial Infarction (NRMI-USA), Magid et al4 demonstrated that in patients who presented STEMI during the night, it took longer to perform a primary PCI than a fibrinolysis. The same authors concluded that 33 647 patients that were treated with primary PCI had a higher hospital mortality rate when symptoms began at night, in relation with the longer delay of reperfusion. In a similar way to the above studies, our group recently5 published the results of STEMI patients who were treated with primary PCI between the hours of 8:00 and 18:00 and between 18:00 and 8:00. We studied 90 consecutive patients with STEMI who had been treated with primary PCI, and the results obtained were worse when the PCI was performed between 18:00 and 8:00. On the other hand, other studies have not shown the REFERENCES