1999 Volume 10 Issue 2 Pages 81-90
Purpose: To clarify the clinical characteristics of patients with out-of-hospital cardiopulmonary arrest (OHCPA) due to acute myocardial infarction (AMI). Methods: From November 1985 to August 1996, 257 consecutive patients were successfully resuscitated from OHCPA of non-traumatic cause. Among them, forty seven patients (18.3%) were found to have AMI and subject to this study (CPA group). Six hundred and fifty one patients were admitted alive in the same period with the diagnosis of AMI within 24 hours after the onset of symptoms and served as control (nonCPA group). Results: The time of onset of AMI in the CPA group had a circadian variation with peak incidence between 10 to 12AM and 8 to 12PM. In 72% of the CPA group, sudden cardiac arrest occurred at home. While 71% of the CPA group was admitted by ambulance within one hour after the onset of AMI, in the rest of patients (29%) the emergency call was delayed more than one hour after the onset of AMI. The electrocardiogram on arrival showed ventricular fibrillation (Vf) in 40%, electromechanical dissociation in 21% and asystole in 38%. In comparison with the nonCPA group, the rate of acute anteroseptal MI was significantly greater in the CPA group (72% vs 38%, p=0.016), so were the rates of old MI (32% vs 12%, p=0.0002) and recent anginal episode (53% vs 29%, p=0.0003). In the CPA group 64% of cases had been under medical care for ischemic heart disease. The rate of smoking history in the CPA group was significantly lower than in the nonCPA group (40% vs 59%, p=0.01). Chest radiograph on arrival revealed pulmonary congestion in 17% of the CPA group and in 6.5% of the nonCPA group (p=0.015). In 13 cases studied by coronary angiogram, the infarct related coronary arteries were occluded totally at their proximal portion in all cases. Two cases were studied by autopsy. In reviewing the coronary arteries of 20 cases, including 5 other cases in whom coronary angiograms were studied at other institutions before the episode of CPA, 50% of the cases were found to have multivessel disease and 25% had left main trunk lesions in the coronary arteries. Four out of 6 patients who received bystander CPR discharged home (66%), while only 3 out of 41 patients (7%) who could not receive bystander CPR did so (p=0.006). Vf on hospital arrival was significantly related to a favorable survival rate (60% vs 26%, p=0.049). Conclusion: Sudden cardiac arrest was frequently observed in patients with anteroseptal AMI who had histories of MI, recent anginal episode, multivessel lesions or left main trunk lesions in their coronary vessels. The underlying cause of cardiac arrest seemed to be cardiac failure in 17% of the cases. Bystander CPR or Vf on arrival seemed to befavorable outcome factors.
