Non-invasive assessment of functionally significant coronary stenoses through mathematical analysis of spectral ECG components

OBJECTIVES: The aim of this study was to evaluate the accuracy of the Multifunction CardioGram (MCG) in detecting the presence of functionally significant coronary ischaemia. METHODS AND RESULTS: This prospective study evaluated the accuracy of the MCG, a new ECG analysis device used to diagnose ischaemic coronary artery disease (CAD). A consecutive 112 participants suspected to have CAD who were scheduled for elective coronary angiography (CAG) from October 2012 to December 2013 were examined. Their predictive values of relevant ischaemia were measured by MCG, standard ECG and Framingham Risk Score (FRS) and compared. Five levels of ischaemia based on CAG findings adjusted by fractional flow reserve (FFR) values and three levels of MCG score of high, borderline or low were used. The MCG (OR=2.67 (1.60 to 4.44), p<0.001) was the only test significantly associated with ischaemia level. The FFR values for individual MCG scores with low, borderline and high were 0.77 (0.70 to 0.86), 0.78 (0.71 to 0.82) and 0.69 (0.65 to 0.77), respectively, p=0.042. A high MCG score had a specificity of 90.4% (87.0% to 93.9%) in model 1 adjusted by FFR≤0.8 threshold and of 87.0% (83.2% to 90.8%) in model 2 adjusted by FFR≤0.75 threshold, and a negative predictive value of 82.5% (78.3% to 86.7%) in model 1 and of 83.8% (79.6% to 87.9%) in model 2 for the prediction of severe ischaemia. CONCLUSIONS: The MCG showed high specificity with a high negative predictive value, suggesting that the MCG could be used not only to identify functionally significant ischaemia but to reduce unnecessary CAGs. TRIAL REGISTRATION NUMBER: UMIN ID: 000009992.