Annals of Noninvasive Electrocardiology : The Official Journal of the International Society for Holter and Noninvasive Electrocardiology, Inc, 10 November 2019, Pages e12722 An initial exploration of subtraction electrocardiography to detect myocardial ischemia in the prehospital setting. Ter Haar CC, Peters RJG, Bosch J, Sbrollini A, Gripenstedt S, Adams R, Bleijenberg E, Kirchhof CJHJ, Alizadeh Dehnavi R, Burattini L, de Winter RJ, Macfarlane PW, Postema PG, Man S, Scherptong RWC, Schalij MJ, Maan AC, Swenne CA

Background

In the prehospital triage of patients presenting with symptoms suggestive of acute myocardial ischemia, reliable myocardial ischemia detection in the electrocardiogram (ECG) is pivotal. Due to large interindividual variability and overlap between ischemic and nonischemic ECG-patterns, incorporation of a previous elective (reference) ECG may improve accuracy. The aim of the current study was to explore the potential value of serial ECG analysis using subtraction electrocardiography.

Methods

SUBTRACT is a multicenter retrospective observational study, including patients who were prehospitally evaluated for acute myocardial ischemia. For each patient, an elective previously recorded reference ECG was subtracted from the ambulance ECG. Patients were classified as myocardial ischemia cases or controls, based on the in-hospital diagnosis. The diagnostic performance of subtraction electrocardiography was tested using logistic regression of 28 variables describing the differences between the reference and ambulance ECGs. The Uni-G ECG Analysis Program was used for state-of-the-art single-ECG interpretation of the ambulance ECG.

Results

In 1,229 patients, the mean area-under-the-curve of subtraction electrocardiography was 0.80 (95%

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0.77-0.82). The performance of our new method was comparable to single-ECG analysis using the Uni-G algorithm

sensitivities were 66% versus 67% (p-value > .05), respectively; specificities were 80% versus 81% (p-value > .05), respectively.

Conclusions

In our initial exploration, the diagnostic performance of subtraction electrocardiography for the detection of acute myocardial ischemia proved equal to that of state-of-the-art automated single-ECG analysis by the Uni-G algorithm. Possibly, refinement of both algorithms, or even integration of the two, could surpass current electrocardiographic myocardial ischemia detection.

Keywords: Vectorcardiogram, Acute myocardial ischemia, Serial Electrocardiography, Subtraction Electrocardiography

Ann Noninvasive Electrocardiol. 2019 Nov:e12722