Preinfarction angina protects against out-of-hospital ventricular fibrillation in patients with acute occlusion of the left coronary artery.
OBJECTIVE
The goal of this study was to evaluate the effect of preconditioning on out-of-hospital ventricular fibrillation (VF) in patients with acute myocardial infarction (AMI).


BACKGROUND
More than half of the deaths associated with AMI occur out of the hospital and within 1 h of symptom onset. In humans, preinfarction angina (PA), which can serve as a surrogate marker for preconditioning, reduces infarct size, but the protective effect against out-of-hospital VF has not been investigated.


METHODS
Preinfarction angina status and acute coronary angiographic findings of 72 consecutive patients with AMI complicated by out-of-hospital VF were compared with 144 matched controls without this complication.


RESULTS
Preinfarction angina is associated with a lower risk for VF (odds ratio [OR]: 0.40, 95% confidence interval [CI]: 0.18 to 0.88). In patients with acute occlusion of the left coronary artery (LCA) (n = 136), the risk reduction is pronounced (OR: 0.25, 95% CI: 0.10 to 0.66), whereas, in patients with acute occlusion of the right coronary artery (RCA) (n = 67), the protective effect of PA on VF was not observed (OR: 2.25, 95% CI: 0.45 to 11.22). Subgroup and multivariate analyses show that the protective effect is independent of cardiovascular risk factors, preinfarction treatment with beta-adrenergic blocking agents or aspirin, the presence of collaterals or residual antegrade flow or the extent of coronary artery disease.


CONCLUSIONS
Preinfarction angina protects against out-of-hospital VF in patients with acute occlusion of the LCA. This protection is independent of risk factors or coronary anatomy. A larger study is needed to examine the apparently different effect in patients with acute occlusion of the RCA.
Gheeraert
P J
PJ
Department of Cardiology, University Hospital, Gent, Belgium. peter.gheeraert@rug.ac.be
Henriques
J P
JP
De Buyzere
M L
ML
De Pauw
M
M
Taeymans
Y
Y
Zijlstra
F
F
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000368:Aged; D000704:Analysis of Variance; D000787:Angina Pectoris / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology; D001241:Aspirin / Q000627:therapeutic use; D016022:Case-Control Studies; D003097:Collateral Circulation; D017023:Coronary Angiography; D003326:Coronary Circulation; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000209:etiology* / Q000401:mortality / Q000628:therapy; D005260:Female; D006785:Hospitals, University; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000209:etiology* / Q000401:mortality / Q000628:therapy; D009426:Netherlands / Q000453:epidemiology; D010351:Patient Discharge; D012307:Risk Factors; D012720:Severity of Illness Index; D016019:Survival Analysis; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000401:mortality
D000319:Adrenergic beta-Antagonists; D001241:Aspirin