Pre-Conditioning in Non-ST Elevation Myocardial Infarction Fact or Fiction

Background: Several studies have demonstrated the protective effects of preconditioning in STEMI but it remained uncertain in patients with non STEMI.Aim: To evaluate preconditioning in non STEMI.Patients and Methods: 80 patients with first non-STEMI who were admitted to Ain Shams University Hospitals were divided into group one: 40 patients without preinfarction angina and group two: 40 patients with preinfarction angina and subdivided into group 2A: With preinfarction angina within 12 hours before admission and group 2B: With delayed preinfarction angina 12 hours preinfarction angina.Methods: All patients received standard treatment for non-STEMI.ECG, cardiac enzymes, coronary angiography and informed concents were done for all patients. Echocardiography was done to every patient before discharge.Results: Higher myocardial biomarkers and lower LV ejection fraction was found in group 1 than group 2 (51±6.7 vs 57±6.5 respectively p-value 0.006) total CPK in group 1: 162±45 vs 680±90 in group 2 with p-value 0.016. All major cardiac events were more in group 1. Incidance of recurrent ischemia was 65% in group 1 and 30% in group 2 (p-value 0.008). Timing of preinfarction angina did not affect the inhospital outcome and did not influence myocardial protection.Conclusion: Preinfarction angina is aprotective mechanism in patients with non STEMI regardless the timing of preinfarction angina.