Background: Ischemic heart disease (IHD) has the highest mortality rate in the globe. This returns to the poor diagnostic and therapeutic strategies including the early prevention methods. Aims: To assess the changes in the single channel electrocardiography (SCECG) in rest and on exercise test in patients with vs without IHD confirmed by stress computed tomography myocardial perfusion (CTP) imaging with vasodilatation stress-test. Objectives: Ischemic heart disease patients frequently have preventable risk factors and causes that lead to the disease appearance. However, the lack of the proper diagnostic and prevention tools remains a global challenge in or era despite the current scientific advances. Material and methods: A cohort, prospective, single center observational study included 38 participants from Moscow. The participants aged ≥ 40 years and given a written consent to participate in the study. Both groups (G1=19 with and G2=19 without myocardial perfusion defect) passed general primary consultation by cardiologist, anthropometric measurements, blood pressure and pulse rate using automatic tonometer, echocardiography, cardio-ankle vascular index, performing bicycle ergometry, recording 3-minutes SCECG (using CARDIO-QVARK) before and just after bicycle ergometry, and then performing CTP. the LASSO regression with nested cross-validation was used to find association between Cardio-Qvark parameters and the existence of the perfusion defect. Statistical processing carried out using the R programming language v4.2 and Python v.3.10 [^R]. Results: The SCECG have significantly higher diagnostic accuracy in compare to bicycle ergometry. The specificity 63.2 % [95 % confidence interval (CI); 0.391 ; 0.833], sensitivity 73.7 % [95 % CI ; 0.533 ; 0.929], and accuracy of the diagnostic method using CARDO-QVARK analysis, area under the curve (AUC) 68.4 % [95 % CI ; 0.527 ; 0.817]. Conclusion: SCECG (Cardio-Qvark) has the potential to improve the diagnostic accuracy of the bicycle ergometry. Other: Further investigations required to uncover the hidden capabilities of Cardio-Qvark in the diagnosis of ischemic heart disease.