Correlation Of Planar QRS-T Angle With Left Ventricular Geometry And Prognosis In Patients With Essential Hypertension

Objective: Planar QRS-T angle is a non-invasive vectorcardiography index that has attracted people's attention in recent years.It reflects the changes of ventricular repolarization and depolarization,and it is related to coronary heart disease,diabetes and hypertension.The relationship between it and left ventricular geometry in patients with essential hypertension is rarely studied.Therefore,we want to collect planar QRST angle and prognosis of patients with essential hypertension,and to investigate whether or not there is a relationship between the planar QRS-T angle and left ventricular geometric patterns.Methods: Three hundred and sixty patients with essential hypertension who had been hospitalized in the First Affiliated Hospital of Dalian Medical University from September 2013 to August 2014 were enrolled in the study.Patients were required to provide medical history,clinical features,medication,etc.Then they underwent a series of medical tests,such as blood biochemical tests.The frontal QRS axis and T-wave axis were included in the reports of the automated ECG machine.The absolute difference between the frontal QRS axis and T-wave axis was defined as planar QRS-T angle.According to the planar QRS-T angle,patients were divided into planar QRS-T angle<45°group,planar QRS-T angle of 45-90° and planar QRS-T angle>90°group.The patients were followed up for an average of 50.5±12.5 months,the endpoint was mortality.The clinical data of the three groups were compared.Then the patients were divided into four left ventricular geometric pattern groups and the differences of planar QRS-T angle between the three groups were compared too.The correlation of planar QRS-T angle level with RWT and LVMI were analyzed.Survival curve and Cox regression were used to analyze the prognosis between different groups.The statistical software SPSS 23.0 was used for all analyses and when P<0.05,significance differences were considered.Results:1.The medical history and general data of the three groups were compared: 360 subjects [age 64(55,72)years,238(66.1%)male] met the inclusion criteria.Among them 157(43.6%)patients presented with planar QRS-T angle >45°,planar QRS-T angle>90° were seen in 21.4%(77/360).There are differences between groups in BMI,SBP,history of diabetes mellitus,diuretic utilization,Cre,QT interval,R axis,T axis,planar QRS-T angle,IVST,LAID,LVPWT,PWT,LVMI,LVEF.The BMI,SBP,history of diabetes mellitus,diuretic utilization,PR interval,QT interval,T axis,planar QRS-T angle,LVPWT,LVMI of planar QRS-T angle>90°group were all higher than those of planar QRS-T angle<45°group,P axis,R axis,LVEF were lower than those of planar QRS-T angle<45°group.Diuretic utilization,Cre,T axis,planar QRS-T angle,IVST,LAID,LVPWT,RWT,LVMI of planar QRS-T angle>90°group were all higher than those of planar QRS-T angle 45-90° group.SBP,T axis,planar QRS-T angle,IVST,LAID,LVPWT,LVMI of planar QRS-T angle 45-90°group were all higher than those of planar QRS-T angle<45°group.2.Comparison and correlation analysis of planar QRS-T angle between different left ventricular geometry groups: The planar QRS-T angle in both the concentric hypertrophy group and eccentric hypertrophy group were higher than that in the normal geometry group and concentric remodeling group(P<0.01).The level of planar QRS-T angle was positive correlated with LVMI(r = 0.231,P = 0.000),and was negative correlated with LVEF(r =-0.213,P = 0.000).Using ROC curve to estimate the predicting value for the left ventricular hypertrophy of essential hypertension of planar QRS-T angle,the area under the ROC curve was 0.652,P = 0.000,95% confidence interval 0.592-0.716.3.Comparison of prognosis among the three groups: 360 patients were followed up for 50.5±12.5 months.the number of death patients was 40 and cardiac death patients was 22.The survival curves of the three groups were statistically different(P= 0.035),Multiple factor COX regression analysis showed that planar QRS-T angle reminded significant(P=0.036)after adjusted by age,history of diabetes mellitus,geometric patterns which were filtrated from univariate regression analysis,and the hazard ratio risk was 2.070.Conclusions:1.The prevalence of planar QRS-T angle was high in patients with essential hypertension,indicating essential hypertension is likely a most common cause of planar QRS-T angle in general population.2.The planar QRS-T angle in both eccentric hypertrophy group and the concentric hypertrophy group were higher than that in the normal geometry group and concentric remodeling group,this findings suggest repolarization abnormalities secondary to the increased LVMI may be the major underlying cause of planar QRS-T angle enlargement in essential hypertension.3.The prevalence of poor prognosis was significantly higher in patients with the planar QRS-T angle>90° group than the planar QRS-T angle<45° group and planar QRS-T angle 45-90° group.