Arrhrythmias and haemodynamic effects associated with early versus late prehospital thrombolysis for acute myocardial infarction.

Abstract

The occurrence of arrhythmias and haemodynamic changes was studied prospectively in 226 consecutive patients who received prehospital thrombolysis for acute ST-elevation myocardial infarction (STEMI) in two Helicopter Emergency Medical Service (HEMS) systems in Southern Finland. Of the 226 patients, 129 were classified as receiving early (pain to treatment-time <90 min) and 97 as late (pain to treatment-time >90 min) treatment. Data on all arrhythmias and haemodynamic disturbances during the prehospital phase were collected. Arrhythmias occurred in 39% of all patients (40% in the early and 38% in the late group). A third of the patients received treatment for their arrhythmia (38% in the early group and 24% in the late group, P = NS). The most common arrhythmia was ventricular extrasystoles, which did not require any treatment in the majority of patients. On arrival of the EMS crew, 14% of all patients were hypotensive (14% in the early and 13% in the late group). After thrombolytic treatment, 7% of all patients became hypotensive (7% of the patients in both groups). The most common treatment for hypotension was fluid administration. Of the 15 patients who received thrombolysis after cardiopulmonary resuscitation (CPR), four patients suffered from arrhythmias and six patients developed hypotension after initiation of thrombolytic treatment. Although arrhythmias and haemodynamic changes were frequent in the prehospital setting after initiation of thrombolytic therapy, severe adverse events were rare. Those requiring therapeutic measures responded well to treatment. The occurrence of events was not related to the timing of thrombolysis in relation to the duration of pain.