Death from myocardial infarction: what are the benefits of early arrival at hospital and thrombolysis?

The potential benefits of early hospital care in the event of myocardial infarction were investigated in a community-based study of all suspected cases of heart attack among people aged under 70 years in the Hunter Region of New South Wales. Between August 1984 and December 1985 acute care data were collected for 1029 cardiovascular events classified as definite myocardial infarction or sudden coronary death; 516 (50%) resulted in death within 28 days from the onset of symptoms and 325 of these deaths (63%) occurred outside hospital. Of 703 people who are known to have reached hospital alive 205 (29%) did so more than four hours after the onset of symptoms. At the time of the study fewer than 1% of patients received streptokinase. To estimate the potential benefits of increased medical care an optimistic scenario was considered in which patients who arrived at hospital more than four hours after the onset of symptoms received medical attention earlier and all eligible patients received thrombolysis. Based on the results of the Second International Study of Infarct Survival (ISIS-2), if streptokinase and aspirin had been used 14% of deaths would have been averted. If, in addition, patients had arrived at hospital earlier and received optimal benefit from thrombolysis another 13% of deaths could have been avoided. These results provide a broader perspective of the potential benefits of improved medical care than can be obtained from hospital-based studies that deal only with those heart attack victims who survive long enough to reach hospital alive.