SUMMARY The clinical entry characteristics and medical history of 142 resuscitated out-of-hospital cardiac arrest victims with coronary heart disease were studied in order to identify factors that affect their longterm survival. The cardiac arrest event was classified as being secondary to an acute myocardial infarction (AMI) in 44% (62 of 142), an ischemic event (IE) in 34% (49 of 142) and a primary arrhythmic event (PAE) in 22% (31 of 142). The majority of patients in all groups had a history of angina pectoris. Twenty-seven percent of the AMI, 55% of the IE, and 71% of the PAE patients had a history of infarction. Ten percent of the AMI, 31% of the IE, and 55% of the PAE had used digitalis before their cardiac arrest. Cardiac arrest was the first cardiac event in 35% of the AMI, 16% of the IE and 6% of the PAE patients. One year after arrest, 89% of the AMI, 80% of the IE and 71% of the PAE were alive (p < 0.01). Covariate analysis for more than 40 variables indicates that a high-risk group that included 22% (31 of 142) of the cardiac arrest victims had 1-and 2-year survival rates of 71% and 55%, respectively, and was characterized as having used digitalis before arrest, experiencing blood urea nitrogen elevation and pulmonary congestion during the hospitalization for the event, and classification of the cardiac arrest event as a PAE. A low-risk group comprised 78% (111 of 142) of the survivors and had 1-and 2-year survival rates of 85%9 and 69%, respectively. These data indicate that cardiac arrest due to coronary heart disease is secondary to several mechanisms related to subsequent survival.

The effect of bystander cardiopulmonary resuscitation (CPR) was studied in 2142 emergency medical service (EMS) cardiac arrest runs. When bystander CPR was administered to cardiac arrest victims, 22.9% of the victims survived until they were admitted to the hospital and 11.9% were discharged alive. in comparison, the statistics for cardiac arrest victims who did not receive bystander CPR were 14.6% and 4.7%, respectively (p < 0.001). A critical factor in patient survival was the amount of time that elapsed before the EMS personnel arrived and administered CPR. Patients who received bystander CPR were more likely to have ventricular fibrillation when the EMS arrived. Other factors relating to patient survival were the location of the victim at the time of the cardiac arrest and the age of the victim. Understanding these factors is important in developing community strategies to treat patients with cardiac arrest out of hospital. (AM HEART J 110:932, 1985.

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