Abstract 14858: Circadian Variations Of Ischemic Burden Among Patients With Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention
Background It is well known that cardiovascular physiology and pathophysiology exhibits circadian rhythms. For instance, myocardial infarction rates increase in the early hours of the morning. Recently, time of the day variations in infarct size has been suggested in experimental models of myocardial infarction. The aim of this study is to investigate whether circadian rhythms could cause differences in ischemic burden in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).
Methods and Results In 353 consecutive patients with STEMI treated by PPCI, time of symptom onset, peak creatine kinase (CK) and follow-up at 30 days were obtained. We divided 24 hours into 4 time groups based on hour of symptom onset (0:00 - 5:59, 6:00 - 11:59, 12:00 - 17:59 and 18:00 - 23:59). There was a statistically significant difference between CK levels among patients with symptom onset between 0:00 and 05:59 when compared to CK levels of patients with symptom onset in any other time group (increase = 38.4 %, p<0.05) (figure 1). These differences remained significant after multivariable analysis and were not explicable by notably different “symptoms-to-hospital” times, “admission-to-needle” times or TIMI flow at the end of the PPCI. To exclude an “out of hours effect”, STEMI patients with symptom onset during the weekend were recorded. Similar significant differences in CK level were observed between 0:00 and 05:59 when compared to any other time group (increase = 63.9 %, p<0.05). The 30-day mortality for STEMI patients with symptom onset occurring between 0:00 and 5:59 was significantly higher than any other time group (p=0.0148).
Conclusion The present study shows circadian variations in infarct size in patients with STEMI treated by PPCI after multivariable adjustment. These results are in line with experimental studies and suggest that myocardium has circadian vulnerability variations to ischemia.
- © 2011 by American Heart Association, Inc.