Life-threatening arrhythmias in anterior ST-segment elevation myocardial infarction patients treated by percutaneous coronary intervention : adverse impact of morphine

Aims Important controversies remain concerning the determinants of life-threatening arrhythmias during ST-segment elevation myocardial infarction (STEMI) and their impact on late adverse events. This study sought to investigate which factors might facilitate ventricular tachycardia (VT) and ventricular fibrillation (VF), in a homogeneous population of anterior STEMI patients defined by abrupt left anterior descending coronary artery (LAD) occlusion and no collateral flow. Mehtods and results The 967 patients, who entered into the CIRCUS (Does Cyclosporine ImpRove Clinical oUtcome in ST elevation myocardial infarction patients) study, were assessed for further analysis. Acute VTNF was defined as VT (run of tachycardia >30 s either self-terminated or requiring electrical/pharmacological cardioversion) or VF documented by electrocardiogram or cardiac monitoring, during transportation to the cathlab or initial hospitalization. VTNF was documented in 136 patients (14.1%). Patients with VTNF were younger and had shorter time from symptom onset to hospital arrival. Site of LAD occlusion, thrombus burden, area at risk, pre-percutaneous coronary intervention Thrombolysis in Myocardial Infarction flow, and ST-segment resolution were similar to that of patients without VTNF. There was no impact of VT/VF on left ventricular remodelling or clinical outcomes. By multivariate analysis, the use of morphine (odds ratio 1.71; 95% confidence interval (1.13-2.60); P = 0.012) was the sole independent predictor of VTNF occurrence. Conclusions In STEMI patients with LAD occlusion, our findings support the view that morphine could favour severe ventricular arrhythmias.