Introduction: Transmitting the prehospital 12-lead ECG has been shown to tremendously improve outcomes in patients with myocardial infarction (MI). Yet emergency personnel do not routinely transmit the 12-lead ECG to receiving facilities despite the availability of ECG acquisition and transmission capabilities. We sought to describe the behavior and predictors of emergency personnel’s decision to transmit or not to transmit the prehospital ECG of patients with suspected MI.
Methods: This was a prospective, observational, cohort study that enrolled consecutive chest pain patients transported by Emergency Medical Services to participating UPMC facilities in Pittsburgh between 2013 and 2014. Prehospital and inhospital clinical data elements were collected from charts. The presence of MI was defined according to the universal definition of MI (detection of cardiac biomarkers plus evidence of ischemia). Paramedics’ impression of initial ECG was categorized as: normal sinus rhythm, ischemic ST changes, arrhythmia (Atrial fibrillation, heart blocks, ventricular tachyarrhythmia, or pacing), or undocumented.
Results: This study enrolled 2065 patients (age 56±17, 53% males, 36% transmitted and 64% non-transmitted cases). Compared to non-transmitted cases, chest pain patients with transmitted ECGs had higher prevalence of MI (13.2% vs. 4.3%, p<0.001), and were more likely to be older (59 vs. 55 years), to be male (58% vs. 50%), and to have ischemic ST changes on the initial ECG (4% vs. 1%). Emergency personnel had 64% sensitivity and 65% specificity to transmit the ECG of MI patients. More importantly, among the 155 patients with acute MI (99 transmitted and 56 non-transmitted), 10% of the non-transmitted cases had ischemic ST changes suggestive of STEMI, compared to 15% among the transmitted cases.
Conclusions: Older age, male sex, and impression on the initial ECG play a significant role in the decision to transmit or not to transmit the ECG. However, paramedics have only moderate accuracy in risk stratifying suspected MI, manifested in failure to transmit one third of MI cases. Systemic over-reading of all ECGs by a medical command physician can improve the risk-stratification process.