Pre-hospital and hospital time delays in thrombolytic treatment in patients with suspected acute myocardial infarction. Analysis of data from the EMIP study. European Myocardial Infarction Project.

OBJECTIVES

To compare the components of the time delay involved in pre-hospital and hospital thrombolytic therapy in patients presenting with suspected acute myocardial infarction.

MATERIAL AND

METHODS

From October 1988 to January 1992 a total of 198 mobile emergency units in 15 European countries and Canada randomized 5469 patients to receive either pre-hospital thrombolytic treatment, followed by placebo in hospital (pre-hospital group), or pre-hospital (hospital group) in the European Myocardial Infarction Project trial. We performed a post hoc analysis of these data to correlate components of the interval between symptom onset and treatment with baseline patient characteristics.

RESULTS

The delay between onset of symptoms and calling for an ambulance was significantly longer for female patients (P = 0.0001), older patients (> 65 years old; P = 0.0001), those who had experienced pain within the previous 24 h (P = 0.0001), and those with pulmonary oedema (P = 0.04). This delay was significantly shorter in patients with previous myocardial infarction (P = 0.02), those with ventricular fibrillation (P = 0.0001), and those in shock (P = 0.0001). The delay between the two injections was significantly longer for older patients (> 65 years old; P = 0.02), those with previous myocardial infarction (P = 0.03), and those in shock (P = 0.003).

CONCLUSIONS

Action undertaken to reduce delays between symptom onset and treatment should focus on modifiable factors such as patients who are likely to be late callers i.e. women and those over 65 years of age.