Cancelled Stemi Patients: Who, What, Where, and Why?

Abstract

PURPOSE:Catheter based revascularization is the treatment of choice for a STEMI. Since "TIME IS MUSCLE", any intervention to shorten the time from first medical contact to balloon inflation is felt to have benefit. The ability to perform a 12 lead ECG in the field allows the pre-hospital detection of a STEMI and activation of the STEMI team. However, false activation can result in wasted manpower and increased cost. Prior studies have reported a false activation rate of 12-36%. Reasons for false activation have been investigated, and found to commonly be due to poor quality and mis-interpretation of the 12 lead in the field. What have not been reported are the characteristics and outcome of the group of patients whose STEMI is cancelled. The purpose of this report is to describe who are the cancelled STEMI patients, what was their presenting complaint, where did the activation occur, why was it cancelled and what was their outcome. METHODS:All STEMI activations presenting to a community based Emergency room from January 2015 through December 2019 were reviewed. Data included; site and reason of activation, source and reason for cancellation, co-morbid medical conditions and outcome. RESULTS:During the 5 year interval, a total 418 STEMI cases resulted in activation of the STEMI team by EMS or the ED. Of these 143 were cancelled representing 34.2% of activated STEMI's. Of the cancelled STEMI patients, 107 (75%) were activated in the field and 36 (25%) in the ER. The average age was 67 years (range 25-96). Cardiology was involved with the decision to cancel in 98%. Three chief complaints accounted for 82% of the cases: Chest Pain 44%, shortness of breath 21%, and altered mental status including syncope 21%. Out-of-hospital-cardiac-arrest accounted for 7%. The reasons for cancellation were: a poor quality or false positive ECG 54%, Acute Coronary Syndrome -NSTEMI 34%, Co-morbid medical conditions 12%. The group of cancelled STEMI patients had a mortality of 12.5% after arrival to the ER and before discharge. CONCLUSIONS:The cancelled STEMI patient is not always a false alarm. While they may not be suffering from a coronary occlusion requiring emergent revascularization, many have significant medical conditions requiring emergent care and have a mortality during the index presentation that is 3x higher than the STEMI patients. CLINICAL IMPLICATIONS:The cancelled STEMI patient represents a clinical challenge to the Emergency Room team. An immediate decision needs to be made to continue with or cancel the STEMI. This skill set requires recognition of the common ECG causes for false activation and a focused assessment for significant co-morbid medical conditions. Knowledge of the ECG causes can be used as teaching points to first responders and ER physicians. This has the potential to result in fewer false activations and less wasted manpower.