Utilisation of emergency medical service among Singapore patients presenting with ST-segment elevation myocardial infarction: prevalence and impact on ischaemic time

BACKGROUND: Previous studies in Western countries found that the emergency medical service (EMS) was under-used in patients with myocardial infarction. AIM: We sought to determine the prevalence of immediate EMS utilisation among Singapore patients presenting with ST-segment elevation myocardial infarction (STEMI), and correlated the use of the EMS with the symptom-to-balloon and door-to-balloon times. METHODS: We studied 252 patients admitted with STEMI to our institution from August 2008 to September 2009. Information regarding demographic characteristics, whether EMS was used, reperfusion procedural details and mortality rates were collected prospectively. RESULTS: Among the recruited patients, 89 (35.3%) used the EMS (EMS group) and 163 (64.7%) did not use the EMS (non-EMS group). In the latter group, 98 (60.1%) arrived at our institution through their own transport, 56 (34.4%) first consulted general practitioners, and 9 (5.5%) initially consulted another hospital without acute medical services. Among the 245 (out of 252, 97.2%) patients who received percutaneous coronary intervention (PCI), the EMS group was more likely to undergo primary PCI (P= 0.003) while the non-EMS group was more likely to undergo non-urgent PCI (P= 0.002). In patients who underwent primary PCI, the EMS group had a shorter symptom-to-balloon time (average difference 81.6 min, P= 0.002). The door-to-balloon time was similar for both groups. CONCLUSION: Despite the availability of a centralised EMS, 64.7% of patients with STEMI did not contact EMS at presentation. These patients were less likely to receive primary PCI and had a significantly longer symptom-to-balloon time.