METHOD FOR INCREASING DIAGNOSTIC ACCURACY OF STRESS ECG TEST FOR DETECTING MANIFESTATIONS OF TRANSIENT MYOCARDIAL ISCHEMIA Russian patent published in 2019 - IPC A61B5/02 A61B5/205 

FIELD: medicine.

SUBSTANCE: invention relates to medicine, in particular to cardiology, and can be used as an electrocardiographic screening method for diagnosing episodes of myocardial ischemia as a manifestation of coronary heart disease (CHD). This method, using the stress test method, involves a metered increase in physical activity, control of blood pressure, heart rate, METs, registration of electric cardiac signals (ECSs), pre-processing of the ECSs with determining the ST-segment displacement, characterized in that the following procedures are additionally carried out: determining the anthropometric parameters of the patient's torso by measuring width 2a and thickness 2b of the torso; determination of the coordinates of the electrodes using the formulas x=rsin(ϕ); y=-rcos(ϕ), where r, which is the distance from the center of the cross section of the torso to the electrode, is determined using the formula

ϕ – the angle between the straight line connecting the armpits, and the direction to the current electrode; synchronous accumulation of cardiac cycles of the ECSs of electrode leads in the time interval of maximum physical activity according to the formula

where N_k – the number of cardiac cycles on the interval of maximum physical activity, j – the number of the cardiac cycle, i – the number of the time countdown of the cardiac cycle; t_j – the moment of reaching the maximum of the R-wave of the j-th cardiac cycle, ƒ_s – the frequency of digitization of the ECSs; reconstruction of the EEGS of the dipole type, i.e. search for the coordinates and projections of the dipole moment vector of EEGS of the dipole type for all time countdowns of the cardiac cycle t_i by finding the minimum of functionality where u_sn – ECS, read from the n-th electrode; N_E – number of electrodes; u_gn – dipole type EEGS signal calculated for the n-th electrode; (x_g, y_g, z_g) – coordinates of EEGS, (M_x, M_y, M_z) – projections of the dipole moment vector; calculation of the coefficient of change of electrical activity on the ST-T segment by: determining M_ST, modulus of the dipole moment vector in the center of the ST segment; determining M_max, the module of the vector of the dipole moment for the top of the T wave; determining β, the coefficient of change of electrical activity on the ST-T segment according to the formula

making a decision about a positive or negative result of the load test according to the formula

where V_JA – ST-segment offset, the outcome d=+1 means a positive test result – the presence of CHD, d=-1 means a negative test result – the absence of CHD; V_{JA thresh} ≈ -0.1 mV and β_thresh ∈ (2.5; 3.5) – optionally set thresholds of parameters that affect the sensitivity and specificity of diagnostic results.

EFFECT: invention provides an increase in the reliability of diagnosing coronary heart disease during a screening examination using stress ECG test.

1 cl, 10 dwg