Reduction of treatment delay in patients with ST-elevation myocardial infarction: impact of pre-hospital diagnosis and direct referral to primary percutaneous intervention: reply

We appreciate that Quinn and colleagues were interested to read our paper.1 In the county of Aarhus, Denmark, primary percutanous coronary intervention (primary PCI) is the preferred reperfusion therapy in patients with ST-elevation myocardial infarction (STEMI)2 Among patients scheduledfor admission to non-interventional hospitals, a substantial reduction in treatment delay is achievable if pre-hospital diagnosis is combined with referral of patients directly to an interventional hospital.1 In this setting, acquisition of pre-hospital ECGs is mandatory. To triage patients on the basis of clinical grounds alone, as mentioned in the letter by Quinn and Whitbread, is not optional because a substantial number of patients would be transferred to the interventional hospital without having STEMI. However, we do agree with Quinn, Whitbread, Miller-Craig, Keeling, and others3–5 that ‘selected qualified paramedics’ may have the skills for establishing the pre-hospital diagnosis of STEMI, provided that the clinical evaluation is supported by acquisition of ECGs. It is worth noting, however, that Miller-Craig et al.3 did not report the accuracy of the diagnosis of STEMI in their study, and paramedic diagnosis was hypothetical only in the study by Whitbread et al.4 In the study by Keeling et al.,5 treatment was actually based on pre-hospital diagnosis established by doctors with the use of telemedicine; however, paramedic diagnosis was also hypothetical. Moreover, doctors identified 90% of patients with STEMI, whereas paramedics identified 71% only (P=0.001). Consequently, if paramedics had been responsible for the initiation of fibrinolytic therapy, a substantial proportion of patients with STEMI would not have received this treatment. In addition, information concerning the positive predictive value of the diagnosis of STEMI when established by paramedics was not available, i.e. how many patients without STEMI would have received fibrinolysis or been transferred to an interventional hospital for primary PCI? We have demonstrated that pre-hospital diagnosis with the use of telemedicine1 may be an attractive supplement to other pre-hospital diagnostic strategies, and may allow the general population to benefit from a pre-hospital diagnostic approach. We hope that pre-hospital diagnostic programs will be more widely implemented in the future. Regional considerations must decide on the optimal treatment strategy (transfer for primary PCI or pre-hospital fibrinolysis) and which diagnostic strategies to rely on (diagnosis with the use of telemedicine, by paramedics, by ambulance physicians, or by general practitioners).