The aim The aim of the study was to analyse the outcomes of cardiopulmonary resuscitation (CPR) in patients with complicated myocardial infarction (MI) at the prehospital level.

Materials and methods
The study was done at the Moscow A.S. Puchkov ambulance and emergency medical service. 
455 emergency calls for MI were retrospectively and prospectively analysed in 2011-2015. 
Patients were split into two groups: MI with cardiac arrest [CA, n=184; split into successful CPR (n=79, 43%) and unsuccessful CPR (n=105, 57%)] and MI without CA (n=271). 
Analysis of MI and CPR outcomes was done. Barnard's exact test was used for the statistical analysis. Difference was considered significant at P<0.05.

Results

CPR was significantly less successful in females [here and below – survived 38,6% vs. deceased 61,4%, p=0,009 - can be explained by the predominance of non-shockable rhythms (57,7% vs. 22,7%)], aged 60-80 y.o. (36,6% vs, 63,4%), onset of symptoms earlier than 3 hrs before ambulance arrival (32,9% vs. 67,2%), unstable angina for 3 days prior MI (29,6% vs. 70,4%), pain score 7-10 (28,9% vs. 71,1% - probable increase of the zone of myocardial necrosis). 
CPR success rate was lower in ST elevation (42,3% vs. 57,7%), repeated MI (34,0% vs. 66%), anterior lesion (36,9% vs. 63,1%), in morphine administration (38,5% vs. 61,5%), pulmonary edema (19,2% vs. 80,8%), cardiogenic shock (34,5% vs. 65,5%) and their associations; unconsciousness (33,7% vs. 66,3%) or agitation (35,7% vs. 64,3%) on ambulance arrival.
Conclusions. CPR in patients with MI was minimally successful in the following cases: onset of MI symptoms earlier than 3 hours before ambulance arrival, unstable angina for three days prior MI, pulmonary edema and pulseless electrical activity

1 - Outcomes of cardiopulmonary resuscitation (CPR) in patients with complicated myocardial infarction at the prehospital level