The Relationship Between Frontal QRS-T Angle And Prognosis Of Ischemic Cardiomyopathy

Background: QRS-T angle is an index derived from electrocardiogram,which represents the electrical activity of cardiac myocytes and the angle between depolarization and repolarization of ventricular myocytes.According to the different measurement methods,it can be divided into spatial QRS-T angle and frontal QRS-T angle.Spatial QRS-T angle needs to be calculated on the basis of three-dimensional space coordinates,which is difficult to obtain clinically.Frontal QRS-T angle is an approximate value of spatial QRS-T angle,which can be directly measured by electrocardiograph and obtained by simple calculation.Spatial QRS-T angle and frontal QRS-T angle have similar predictive value in risk assessment.In recent years,a large number of studies have shown that frontal QRS-T angle has a good value for the prognosis of various diseases.Objective?method: To explore the relationship between frontal QRS-T angle and prognosis of patients with ischemic cardiomyopathy.Methods: 1.801 patients with ischemic cardiomyopathy were selected from the Department of Cardiovascular Medicine,First Hospital of Jilin University from January 1,2013 to December 31,2013.According to the exclusion criteria,379 patients were excluded,and 422 patients were included in the study.They were followed up for 5 years.The deadline for follow-up was 31 December 2018.General information,past medical history and examination results within 24 hours of admission were collected.According to whether major cardiovascular endpoint events occurred during the follow-up period,the patients were divided into event group and non-event group,331 cases in event group and 91 cases in non-event group.Statistical analysis was performed.2.Subgroup analysis was performed in patients with atrial fibrillation,ventricular arrhythmia,complete left bundle branch block and complete right bundle branch block.Four groups,a,b,c and d,were used to analyze the diagnostic value of frontal QRS-T angle in the prognosis of patients with ischemic cardiomyopathy.Result: Among the selected patients,there were 251 males and 171 females.In the event group,male n = 196 cases(59.2%),female N = 135 cases(40.8%),non-event group,male n = 55 cases(60.4%),female N = 36 cases(39.6%)and P = 0.833 had no statistical significance;in terms of age,the total average age of the selected patients was 68.12 + 10.96 years old,and the average age of the event group(68.51 +±10.94 years old)was higher than that of the non-event group(66.71 ± 11.02 years old).There was no statistical significance(p > 0.05).There were 256 patients with hypertension,including 209 cases in the event group(63.1%)and 47 cases in the non-event group(51.6%).There was a significant difference between the two groups(p < 0.05).161 patients with diabetes mellitus,the event group(n = 135 cases,40.8%)was significantly more than the non-event group(n = 26 cases,28.6%,P = 0.034),there was a significant difference between the two groups.In the cardiac function classification,9 cases(2.7%)were in the event group of NYHA I patients,3 cases(3.3%)were in the non-event group,321 cases(97.0%)were in the event group of NYHA grade(> II)patients and 89 cases(97.8%)were in the non-event group.The difference was statistically significant(p < 0.05).There were 205 cases of concurrent arrhythmia,178 cases(53.9%)in event group and 27 cases(29.7%)in non-event group,respectively.The difference was statistically significant.The mean values of NT-pro BNP in event group and non-event group were 10437.15 ±17273.27)and 6891.51 ±9005.10,respectively.The results of event group were significantly higher than that of non-event group.The results of LVEF between two groups were 37.04% ±9.40% and 45.76% ±11.18%,respectively.The left ventricular ejection fraction of event group was significantly lower than that of non-event group.In event group,the frontal QRS-T angle was 69°(19°,109°),and non-event group.The index in the event group was 43 °(1 °,88 °),which was significantly higher than that in the non-event group.The left ventricular end-diastolic diameter was 60.60 mm ±6.90 mm in the event group and 57.47 mm ±8.37 mm in the non-event group.The p value between the two groups was 0.048(p<0.05).The QRS time limit was 104.46 ms± 25.56 ms in the event group and 102.73 ms± 19.19 ms in the non-event group.There was a significant difference between the two groups(p < 0.05).In the analysis of subgroups a,b,c and d,the difference of frontal QRS-T angle between event group and non-event group was statistically significant(p < 0.05).In group a,the frontal QRS-T angles of the event group and the non-event group were 84.00 °(11.50 °,116.00 °)and 12.00 °(0.00 °,72.00 °),respectively.It can be seen that the median of the event group was significantly higher than that of the non-event group.In the patients with MVA,the frontal QRS-T angle was 74.50°(36.75 °,121.50 °)in the event group and 43.50 °(3.00 °,72.25 °)in the non-event group.Among the patients with ischemic cardiomyopathy combined with LBBB and RBBB,the frontal QRS-T angles of the event group were 72.00 °(18.00 °,120.50 °),99.50 °(19.00°,125.00 °),13.00 °(0.00 °,70.50°)and 0.00 °(0.00°,46.50°)in the non-event group,respectively.It can be seen that the frontal QRS-T angle of the event group was significantly larger than that of the non-event group between the c and d groups.Both groups have an impact on the prognosis of patients with ischemic cardiomyopathy.When the four groups were analyzed by ROC curve,the results showed that the increased frontal QRS-T angle could be used as a diagnostic value for the prognosis of ischemic heart disease with AF,MVA,LBBB and RBBB.The sensitivity of RBBB was the best(p=0.019,95% CI 0.677-1.000),and the specificity of LBBB was the best(p=0.022,95% CI 0.652-0.857).Among the four subgroups,patients with LBBB and MVA had higher specificity of frontal QRS-T angle in the diagnosis of prognosis(LBBB group: sensitivity 48.9%,specificity 92.3%,MVA group: sensitivity 48.5%,specificity 90.9%)while patients with RBBB had higher sensitivity(sensitivity 81.3%,specificity 80.0%).Only when frontal QRS-T angle > 15.5 °,it had higher specificity for these patients.Diagnostic value.Conclusion: 1.Frontal QRS-T angle is significantly different between event group and non-event group.Frontal QRS-T angle is independent risk factors for ischemic cardiomyopathy.2.With the increase of frontal QRS-T angle,the probability of occurrence of events increases and the prognosis becomes worse.The frontal QRS-T angle has certain predictive value for the prognosis of patients with ischemic cardiomyopathy.3.When patients with ischemic cardiomyopathy combined with AF,MVA,LBBB and RBBB,the frontal QRS-T angle has a higher diagnostic value for their prognosis.The frontal QRS-T angle of patients with RBBB is more sensitive to them,and the frontal QRS-T angle with LBBB is more specific.