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Editor,—Rao and Joseph’s correspondence inHeart 1 highlighted the reduction in time to administration of thrombolytic therapy by direct admission of patients with suspected acute myocardial infarction to the coronary care unit (CCU) by ambulance staff who had been trained in reading ECGs.
There are four models for admission to hospital of patients with suspected acute myocardial infarction:
(1) The patient is evaluated in the A&E department where the first ECG is recorded, then the patient is admitted to CCU where thrombolytic therapy is administered
(2) The patient is admitted to the A&E department, the ECG is recorded and thrombolytic therapy administered2
(3) The patient is admitted directly to the CCU after out-of-hospital ECG recording by paramedics or general practitioners
(4) ECG is recorded before hospital admission (at home or in the ambulance) by paramedics and transmitted immediately by “telephone” to the receiving CCU where the attending cardiologist can analyse it3; thrombolytic therapy may be administered before admission to the A&E department.
The last model is quite novel and does not consume additional resources as large numbers of ambulance personnel will not require training in reading ECGs and the A&E department does not need to evolve a system for admitting suitable patients directly to the CCU. The ECG diagnostic accuracy in one study was 92% in the typical chest pain group with ischaemic ST segment changes.3 The time to ECG recording was shorter when done in the prehospital setting than when done after admission to the A&E department (mean (SD) 8 (6)v 21 (12) minutes; p < 0.001).
Other factors may influence the delay to thrombolytic treatment and the method of administration is important as bolus administrations needs less time than an infusion.1 In addition, the overall “pain to needle time” is important in reducing infarct size and improving survival. Koren et al’s study4 first demonstrated that early administration of thrombolytics provided a gain in terms of left ventricular (LV) function and necrotic tissue mass if the “time to needle” was less than 90 minutes. The delay in administering thrombolytics, by infusion or bolus, was not as important as overall “pain to needle time” in reducing infarct size and ameliorating LV function.5
Therefore, greater use of ECG telephonic transmission and reporting, and prehospital bolus administration of thrombolytics may be significant in reducing infarct size and improving survival6 as they might shorten the “pain to needle time”.