[Circadian variation in the effectiveness of reperfusion therapy in ST-segment elevation myocardial infarction treated with primary angioplasty and circadian associations with prognosis].

Objectives: To explore circadian variation in the effectiveness of percutaneous transluminal coronary angioplasty (PTCA) to treat ST-elevation myocardial infarction (STEMI) To explore the effects of circardian variation on infarct extension and in-hospital complications.

Material And Methods: Observational retrospective cohort study including patients with PTCA-treated STEMI in a tertiary care university hospital between March 2003 and August 2009. The independent variable of interest was the time of onset of STEMI symptoms, grouped in 6-hour time frames.