Strategies for pre-hospital thrombolysis: an overview

Improvement in survival as a result of thrombolytic therapy in patients with myocardial infarction is determined by the delay between coronary occlusion and reperfusion. Treatment at home can reduce this delay, provided that appropriate patients can be identified. Different strategies for pre-hospital thrombolysis have been developed. Most studies require ECG confirmation of evolving myocardial infarction. In many, the ECG is interpreted by a physician in the ambulance. Others transmit the ECG to a remote physician or use computer analysis of an ECG made 'on the spot', A few studies use no ECG criteria at all. The pooled data show that with physician interpretation, 723 patients in 14 studies could be treated within 103 min after onset of symptoms (range 60-138 min) with a time gain of 51 min (range 30-74 min), compared with thrombolytic treatment after hospital admission. The therapeutic delay was 93 +/- 45 min (SD) with time gains of 62 and 86 min in two studies with ECG transmission (61 patients). In another study using computer analysis, ambulance nurses were able to treat 300 patients within 102 +/- 63 min after onset of symptoms, resulting in a time gain of 48 +/- 2 min. Without ECG confirmation, cardiologists accompanying the ambulance could administer thrombolysis within 83 +/- 4 min after onset of symptoms with a time gain of 45 min in one study. The diagnostic accuracy of this last approach was 42%. With each of the four approaches, patients can be treated within approximately 100 min after onset of symptoms, resulting in a time gain of 45 min or more.(ABSTRACT TRUNCATED AT 250 WORDS)