High-Frequency ECG for Detection of Myocardial Ischemia Associated with Right Coronary Artery Stenosis in IHD Patients

The aim of the investigation was to study the parameters of high-frequency ECG in leads V-1, V3R, V4R, V5R, V6R as additional diagnostic criteria for detecting the areas of myocardial ischemia associated with stenosis of the right coronary artery (RCA) in IHD patients. Materials and Methods. The study involved 47 patients who underwent selective coronary angiography (SCA) for detection of IHD. The patients were divided into two groups based on the SCA results: group 1 included 28 patients with hemodynamically significant RCA stenosis; group 2 consisted of 19 patients with hemodynamically non-significant RCA stenosis. Prior to SCA, all patients underwent resting high-frequency ECG recording in 12 conventional leads and in leads V3R-V6R for 5 min. The study also involved 15 volunteers with no history of cardiovascular disease or IHD symptoms (control group) who underwent ECG in the same leads. The resulting data were processed and analyzed using the ArMaSoft-12-Cardio software ((c) ArMaSoft, 1995-2019, Russia), which made it possible to determine the presence or absence of reduced amplitude zones (RAZ) of the QRS complex in all morphological variants, the root-mean-square (RMS) deviation, and excess kurtosis. Results. Statistically significant differences in the RAZ parameter of the QRS complex were revealed in high-frequency ECG of patients with hemodynamically significant and non-significant RCA stenosis. The RAZ sum in leads V-1, V3R, V4R, V5R, V6R was 7.86 +/- 0.77 and 3.58 +/- 0.53, respectively, while in patients with no IHD signs, it equaled 1.87 +/- 0.43 (p=0.00001). The RMS value in patients with no IHD signs was 3.89 +/- 0.42, in patients with hemodynamically non-significant and significant RCA stenosis it equaled 3.51 +/- 0.34 and 2.73 +/- 0.24, respectively (p=0.008). The kurtosis value was statistically significantly higher in patients with hemodynamically significant stenosis (1.07 +/- 0.12), in contrast to those with hemodynamically non-significant stenosis and without IHD (0.78 +/- 0.05 and 0.64 +/- 0.03, respectively). An average correlation between the value of coronary stenosis and the sum of RAZ scores was found (r=0.66). However, RMS and kurtosis parameters correlate with the degree of RCA stenosis at a lower level. According to ROC analysis, the RAZ parameter showed better diagnostic results compared to RMS and kurtosis. Given the nonparametric nature of the available data, the prognostic capabilities of the studied parameters can be considered satisfactory as shown by the results of binary logistic regression. Conclusion. The RAZ parameter of high-frequency ECG in leads V-1, V3R, V4R, V5R, V6R may serve as an additional diagnostic criterion for identifying the areas of myocardial ischemia associated with RCA stenosis in IHD patients.