Sustained Performance of a "Physicianless" System of Automated Prehospital STEMI Diagnosis and Catheterization Laboratory Activation.

BACKGROUND: Treatment times for primary percutaneous coronary intervention frequently exceed the recommended maximum delay. Automated "physicianless" systems of prehospital cardiac catheterization laboratory (CCL) activation show promise, but have been met with resistance over concerns regarding the potential for false positive and inappropriate activations (IAs). METHODS: From 2010 to 2015, first responders performed electrocardiograms (ECGs) in the field for all patients with a complaint of chest pain or dyspnea. An automated machine diagnosis of "acute myocardial infarction" resulted in immediate CCL activation and direct transfer without transmission or human reinterpretation of the ECG prior to patient arrival. Any activation resulting from a nondiagnostic ECG (no ST-elevation) was deemed an IA, whereas activations resulting from ECG's compatible with ST-elevation myocardial infarction but without angiographic evidence of a coronary event were deemed false positive. In 2012, the referral algorithm was modified to exclude supraventricular tachycardia and left bundle branch block. RESULTS: There were 155 activations in the early cohort (2010-2012; prior to algorithm modification) and 313 in the late cohort (2012-2015). Algorithm modification resulted in a 42% relative decrease in the rate of IAs (12% vs 7%; P < 0.01) without a significant effect on treatment delay. CONCLUSIONS: A combination of prehospital automated ST-elevation myocardial infarction diagnosis and "physicianless" CCL activation is safe and effective in improving treatment delay and these results are sustainable over time. The performance of the referral algorithm in terms of IA and false positive is at least on par with systems that ensure real-time human oversight.

Performance of a new "physician-less" automated system of prehospital ST-segment elevation myocardial infarction diagnosis and catheterization laboratory activation.

The door-to-balloon times frequently exceed the recommended delay. We therefore evaluated the performance of a novel "physician-less" cardiac catheterization laboratory (CCL) activation system relying on the automated electrocardiographic diagnosis alone. From January 2010 to 2012, first responders performed electrocardiograms in the field for all patients with a complaint of chest pain or dyspnea. An automated machine diagnosis of "acute myocardial infarction" resulted in immediate CCL activation and direct transfer without human reinterpretation or transmission of the electrocardiogram. Any activation resulting from a nondiagnostic ECG (no ST-segment elevation) was deemed inappropriate and classified as resulting from either human or machine error. Of 155 activations, 136 (88%) were electrocardiographically appropriate. Of these, 128 patients had a final diagnosis of ST-segment elevation myocardial infarction. A door-to-balloon time of <90 minutes was achieved in 99%, the procedural success was high (94%), and the overall mortality was low (3%). Of the electrocardiographically appropriate activations, 8 (5%) were false-positive results. The remaining 19 activations (12%) were inappropriate. Compared with the electrocardiographically appropriate activations, those with inappropriate activations had significantly greater rates of hypertension (p = 0.0070) and known coronary artery disease (p = 0.0008) and higher presenting heart rates (p <0.0001). The causes for inappropriate activation were approximately evenly split between human and machine error. In conclusion, a combination of prehospital automated ST-segment elevation myocardial infarction diagnosis and "physician-less" CCL activation was safe and effective in ensuring target door-to-balloon times in virtually all patients and resulted in an acceptable rate of inappropriate CCL activation.