Prognostic Value Of The Frontal QRS-T Angle In The Patients With Acute Coronary Syndrome

Background QRS-T angle mainly responses the angle of ventricular depolarzationvector and repolarization vector.It represents a part of the cardiac electric activity,andchanges with the chang of the cardiac structure or function.It is divided into the spatialQRS-T angle and the planar QRS-T angle(that is,the frontal QRS-T angle).The spatialQRS-T angle is an indicator of three-dimension space,complicated calculationed,not easilyobtained from the routine12-lead electrocardiogram.The planar QRS-T angle mainly refersto the angle of the largest frontal QRS vector and the largest frontal T vector, easilyobtained from the routine12-lead electrocardiogram[1]. Many studies show that the frontalQRS-T angle is related with cardiac diseases.Coronary heart disease is the most commontype because of atherosclerosis, It is a kind of common disease that is harm for humanhealth[2], Acute coronary syndrome (ACS) is a severe type of coronary heart disease(CHD).Therefore, we want to collect the frontal QRS-T angle and the prognosis of patientswith acute coronary syndrome (ACS), and discuss the correlation between the two.Objective To explore a method of surface electrocardiogram for assessing thecharacteristics of the frontal QRS-T angle in the all patients with acute coronary syndromewhich are divided into unstable angina group、ST segment elevation myocardial infarctiongroup and non ST segment elevation myocardial infarction group,and the characteristics ofthe frontal QRS-T angle of all the ACS patients with different coronary artery lesionsseverity.To analysis the prognostic value of the frontal QRS-T angle in the patients withacute coronary syndrome.Methods To retrospective analysis828patients with acute coronary syndrome(ACS)in our hospital.The frontal QRS-T angle was calculated automatically according toQRS-wave and T-wave vectors by the electrocardiogram machine.(1)According to thefrontal QRS-T angle,We divide the frontal QRS-T angle《90°、the frontal QRS-Tangle>90°into A group(587cases)、B group(241cases),The clinical indexes of the two groups are analyzed;(2) All the ACS patients contain380cases of unstable angina、283cases of ST segment elevation myocardial infarction and165cases of non ST segmentelevation myocardial infarction, respectively defined as a group、b group、c group, Toanalysis clinical indicators and characteristics of the frontal QRS-T angle among the threegroups;(3)All ACS patients with coronary artery angiography, According to the severity ofcoronary artery lesions,we divide into <20points group,20to40points group,>40points group, To analysis clinical indicators and characteristics of the frontal QRS-T angleamong the three groups;(4)Follow up the prognosis of each ACS patient (such as angina、myocardial infarction recurrence、heart failure、ventricular arrhythmias、cardiac death,etc.),All the ACS patients have197cases with poor prognosis and631cases with non-poorprognosis defined as1group、2group.To take logistic regression analysis of all relatedfactors;(5)To calculate the boundary of the frontal QRS-T angle in diagnosising poorprognosis of the ACS patients.Results1.We divided all the patients into two groups,A group(the frontal QRS-Tangle≤90°,587cases）、B group(the frontal QRS-T angle＞90°，241cases）.Then we findthat the age、history of hypertension、diabetes mellitus、lipid profile、LVS、adverseprognostic was statistically significant between the two groups,And gender、BMI、smoking history、alcohol consumption、admission SBP、ALT、AST、Cr-s、EF、IVSdwas not statistically significant between the two groups.2.All acute coronary syndrome canbe divided into a group、b group、c group, Gender、age、BMI、smoking history、alcoholconsumption、history of hypertension、diabetes mellitus、SBP、TC、HDL-C、LDL-C、AST、ALT、Cr-S、LVS、EF、IVSd was not statistically significant among three groups(P>0.05)，The cases of poor prognosis were statistically significant between a group andb group with a group and c group(P<0.05),The cases of poor prognosis were notstatistically significant between b group with c group(P>0.05),The frontal QRS-T anglewas statistically significant between a group and b group with a group and cgroup(P<0.01),The frontal QRS-T angle was not statistically significant between b groupwith c group(P>0.05).3.According to the Gensini score, All the patients were divided into<20points group、20to40points group、>40points group.Gender、age、BMI、smokinghistory、alcohol consumption、history of hypertension、diabetes mellitus、TC、HDL-C、 LDL-C、IVSd was not statistically significant among three groups (P>0.05),The frontalQRS-T angle was statistically significant between <20points group and20to40pointsgroup with <20points group and>40points group(P<0.05),The frontal QRS-T angle wasnot statistically significant between20to40points group with>40points group(P>0.05),Obstructive CAD of2or3vessels was not statistically significant between <20pointsgroup with20to40points group (P>0.05),Obstructive CAD of2or3vessels wasstatistically significant between <20points group and>40points group with20to40points group and>40points group(P<0.01);4.The frontal QRS-T angle and the prognosisof ACS patients was positively correlated. According to the logistic regressionanalysis,Under the premise the other factors were unchanged,The risk of adverseprognostic of patients when the frontal QRS-T angle were additioned1°will1.018timesthan the original，The frontal QRS-T angle can be used independent predictor of theprognosis of ACS patients.5.The frontal QRS-T angle had optimal sensitivity andspectificity(60%,80%) in diagnosis of the adverse prognostic of ACS patients.Conclusion1. The prevalence of poor prognosis was significantly higher in patientswith the frontal QRS-T angle>90°than in patients with the frontal QRS-T angle≤90°；2.Degree of the frontal QRS-T angle in the myocardial infarction was larger than that inthe unstable angina；3.The larger degree of the frontal QRS-T angle was,The more severitycoronary artery lesions were,It is more likely in patients with multivessel disease;4.Thefrontal QRS-T angle and the prognosis of ACS patients was positively correlated.Thefrontal QRS-T angle can be used independent predictors of the prognosis of ACS patients.