Noninvasive Detection of Functional Myocardial Ischemia: Multifunction Cardiogram Evaluation in Diagnosis of Functional Coronary Ischemia Study (MED‐FIT)

BACKGROUND: Multifunction cardiogram (MCG) is a computer-enhanced, resting electrocardiogram analysis developed to detect hemodynamically relevant coronary artery disease (CAD). Based on data from previous studies suggesting excellent diagnostic accuracy in detecting CAD, MCG (approved by the Food and Drugs Administration) received a Current Procedure Terminology (CPT) code in 2010 in United States. However, there is no previous study validating MCG by using fractional flow reserve (FFR) as the reference standard. METHODS: Multifunction cardiogram Evaluation in Diagnosis of Functional coronary Ischemia sTudy (MED-FIT) was designed as a single-center, prospective study enrolling 100 stable patients with suspected CAD scheduled for coronary angiography. The primary and secondary analyses evaluated the diagnostic performance of the MCG severity score to detect functional myocardial ischemia by FFR ≤0.80, and angiographically significant coronary stenosis (percent diameter stenosis ≥50%) by quantitative coronary angiography. RESULTS: The current analysis set consisted of 91 patients in whom MCG data with adequate quality was obtained. The prevalence of positive functional myocardial ischemia and angiographically significant stenosis in the current study was 42.7% and 41.8%, respectively. Area under the receiver operating characteristics curve (AUC) of the MCG severity score for functional myocardial ischemia and angiographically significant stenosis was low (AUC 0.51, 95% confidence interval [CI] 0.38-0.63, and AUC 0.58, 95%CI 0.46-0.70, respectively). Sensitivity, and specificity of the MCG severity score for functional myocardial ischemia and angiographically significant stenosis was also low (32%/67%, and 37%/72%) using a cutoff value of 4.0. CONCLUSIONS: Diagnostic performance of the MCG severity score was poor for both functional myocardial ischemia, and angiographically significant stenosis.