The Changes Of Thyroid Hormone In Patients With Cardiac Dysfunction And Its Clinical Significance

Objective: To discuss the relationship between changes of thyroidhormones and cardiac function and explore the clinical significance of thyroidhormones in patients with cardiac dysfunction, we had those patients takenmeasure on serum thyroid hormone correlated levels, including triiodo thyroidthyroxine（TT₃）, the thyroxine（TT₄）, free three-triiodothyronine（FT₃）, serumfree thyroxine（FT₄）, thyroid stimulating hormone（TSH） and anti-thyroidperoxidase antibody（TPO-Ab），and cardiac function related factor, includingleft ventricular ejection fraction（LVEF）, Left ventricular end diastolicdiameter（LVEDD） and plasma Brain-type natriuretic peptide（BNP）.Methods:160patients hospitalized in Cardiology Department of theSecond Hospital of Hebei Medical University from July2011to July2012,were enrolled. Inclusion criteria: According to the1994New York HeartAssociation （NYHA） functional classification standard divided into: controlgroup （grade Ⅰ）,the experimental group （grade â…¡, â…¡, Ⅱ）.Gradeâ… , dailyphysical activity is not limited, Gradeâ…¡, daily activities will be fatigue,difficulty breathing, palpitations or angina, mild physical activity is limited,Grade â…¡, lighter than daily activities will be fatigue, difficulty breathing,palpitations or angina, physical activity was limited, Grade â…¡, feel symptomssuch as fatigue, difficulty breathing, palpitations or angina ventriculardysfunction while rest and any physical activity can’t be engaged. Exclusioncriteria:â‘ Medical history of thyroid function hypothyroidism （including subclinical hypothyroidism）, thyroid hyper function psychosis thyroid disease andrecently （2weeks） taking drugs that affect thyroid hormone secretion andmetabolism.â‘¡Medical history of Cancer or malignant tumors, liver or kidneydysfunction, seriously infected, etc. All patients’ fasting serum were taken measure of thyroid function（including TT₃, TT₄, FT₃, FT₄, TSH, TPO-Ab） bymeans of chemiluminescence’s detection, the plasma BNP by means of microparticle immunoassay, meanwhile LVEF, LVEDD were measured by means ofechocardiography. All the data were dealt with spss19.0statistical softwareanalysis, P<0.05was considered to be statistically significant difference.Results:1The comparison of General information among four groups of differentcardiac function grade160subjects were divided into four groups and40people in each group.the results of sex ratio, age, and BMI among the four groups showed nostatistical significance （P>0.05）.2The comparison of thyroid related hormones TT₃, TT₄, FT₃, FT₄, TSH,TPO-Ab in the four groups of different cardiac function gradeTT₃in Experimental group showed statistical significance （P <0.05）, soas FT₃. The values of them in experimental group （gradeâ…¡, â…¡, Ⅱ） comparedto the control group （grade I） were statistical significance. And they declinedas the cardiac dysfunction aggravated progressively. The values of TT₄andTPO-Ab in experimental groups were compared with the control group, thedifference showed no statistical significance（P>0.05）, and among theexperimental groups, the differences showed no statistical significance （P>0.05）. FT₄, TSH value in experimental groups was significantly lower than thecontrol group value, and showed a decreasing trend with the severity ofcardiac dysfunction, but the difference showed no statistical significance（P>0.05）.3The comparison of cardiac function related indicator LVEF, LVEDDand BNP in the four groups of different cardiac function gradeThe values of LVEF in experimental groups were compared with thecontrol group declined as the cardiac dysfunction aggravated progressively,and the difference showed statistical significance（P<0.05）. Otherwise, thevalues of LVEDD and BNP in experimental groups were compared with the control group climbed as the cardiac dysfunction aggravated progressively,and the difference showed statistical significance（P<0.05）. BNP levels werenegatively correlated with LVEF values while positively correlated withLVEDD value.4Correlation analysis of thyroid hormone related indicators of cardiacfunction related indicatorsWith the deterioration of cardiac dysfunction, T₃, FT₃and LVEF declinedgradually, LVEDD and BNP levels increased successively. Those differencewere statistically significant （P <0.05）. TT₃and FT₃compared with LVEFshowed a significant positive correlation. TT₃and FT₃compared with LVEDDshowed a significant negative correlation. TT₃and FT₃compared with BNPwas significantly negatively correlated. FT₄and TSH compared with LVEF,LVEDD and BNP showed no correlation （P>0.05）.Conclusion:1The severity of cardiac dysfunction and thyroid hormone level areclosely related. As cardiac dysfunction, TT₃, FT₃obviously change. The serumFT₃level will be descend as the cardiac function dropping.2The Phenomenon of descend of TT₃and FT₃was called "low T₃syndrome ".3TT₃, FT₃have some correlation with LVEF, LVEDD and BNP.Positively correlated with LVEF, and negatively correlated with LVEDD andBNP. Thus, TT₃and FT₃can better reflect the left ventricular function, andthey could be considered as important risk factors in judgment of cardiacfunction seriousness, treatment and prognosis.