Abstract
Background
There is growing use of prehospital electrocardiograms (ECGs) in establishing early
diagnosis of ST segment myocardial infarction (STEMI) to facilitate early reperfusion.
This study aimed to determine the predictive value of prehospital ECGs interpreted
by nonphysician emergency medical services (EMS) in chest pain presentations.
Methods
In our city of 658,700 people, EMS/paramedics received 21 hours of instruction on
STEMI management, ECG acquisition, and interpretation. Suspected STEMI ECGs were wirelessly
transmitted to and discussed with a physician for possible therapy. ECGs deemed negative
for STEMI by EMS were not transmitted; patients were transported to the closest hospital
without prehospital physician involvement.
Results
From July 21, 2008 to July 21, 2010, there were 5426 chest pain calls to EMS, 380
were suspected STEMI cases. The remaining ECGs were deemed negative for STEMI by EMS.
To audit the nontransmitted ECGs we analyzed 323 consecutive patients over 2 selected
months (January and June 2010) for comparison. Of nontransmitted cases there was 1
missed and 2 STEMIs that developed subsequently. Based on 380 transmitted and 323
nontransmitted cases, the sensitivity and specificity of EMS detecting STEMI were
99.6% and 67.6%, respectively. The positive and negative predictive values for STEMI
were 59.5% and 99.7%, respectively.
Conclusions
Our findings demonstrate nonphysician EMS interpretation of STEMI on prehospital ECG
has excellent sensitivity and high negative predictive value. This finding supports
the use of prehospital ECGs interpreted by EMS to help identify and facilitate treatment
of STEMI. These results may have broad implications on staffing models for first responder/EMS
units.
Résumé
Introduction
On utilise de plus en plus les électrocardiogrammes (ECG) en milieu préhospitalier
pour établir un diagnostic précoce d'infarctus du myocarde avec sus-décalage du segment
ST (IM avec sus-décalage du segment ST) pour permettre une reperfusion rapide. Cette
étude avait pour but de déterminer la valeur prédictive des ECG en milieu préhospitalier
interprétés par des professionnels autres que des médecins des services médicaux d'urgence
(SMU) lors de la manifestation de douleurs thoraciques.
Méthodes
Dans notre ville de 658 700 personnes, les SMU et les ambulanciers paramédicaux ont
reçu 21 heures d'enseignement sur la prise en charge d'IM avec sus-décalage du segment
ST, l'acquisition d'ECG et l'interprétation. Les ECG révélant une suspicion d'IM avec
sus-décalage du segment ST ont été transmis sans fil à un cardiologue pour discuter
du traitement. Les SMU n'ont pas transmis les ECG considérés négatifs en ce qui a
trait à un IM avec sus-décalage du segment ST; les patients ont été transportés à
l'hôpital le plus proche sans demander l'implication du médecin.
Résultats
Du 21 juillet 2008 au 21 juillet 2010, les SMU ont reçu 5426 appels pour des douleurs
thoraciques; 380 ont suscité une suspicion d'IM avec sus-décalage du segment ST. Les
SMU ont considéré tous les autres ECG négatifs en ce qui a trait à un IM avec sus-décalage
du segment ST. Pour vérifier les ECG non transmis, nous avons comparé 323 patients
consécutifs durant 2 mois, soit les mois de janvier et juin 2010. Parmi les cas non
transmis, 1 cas d'IM avec sus-décalage du segment ST a été manqué et 2 cas se sont
manifestés subséquemment. Selon ces 380 cas transmis et 323 cas non transmis, la sensibilité
et la spécificité des SMU dans la détection d'IM avec sus-décalage du segment ST ont
été de 99,6 % et 67,6 %, respectivement. Les valeurs prédictives positive et négative
de l'IM avec sus-décalage du segment ST ont été de 59,5 % et 99,7 %, respectivement.
Conclusions
Nos conclusions démontrent que l'interprétation de l'ECG en milieu préhospitalier
par des professionnels autres que des médecins des SMU obtient une excellente sensibilité
et une valeur prédictive négative élevée. Cette conclusion soutient l'utilisation
des ECG en milieu préhospitalier interprétés par les SMU pour aider à déterminer et
à faciliter le traitement de l'IM avec sus-décalage du segment ST. Ces résultats sont
susceptibles d'avoir des répercussions importantes sur le recrutement du personnel
des SMU et à titre de premiers répondants.
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Article info
Publication history
Published online: June 11, 2012
Accepted:
April 3,
2012
Received:
March 7,
2012
Footnotes
See editorial by Welsh on pages 408-410 and article by Ducas et al. on pages 423-431 of this issue.
See page 436 for disclosure information.
Identification
Copyright
© 2012 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
