Effect of anemia on the frontal QRS-T angle.

BACKGROUND: Anemia is a common health problem worldwide and is associated with a poor prognosis for cardiovascular diseases. It can alter myocardial depolarization and repolarization by affecting the generation and propagation of electrical impulses. The frontal QRS-T angle is a novel marker of the absolute difference between myocardial depolarization and repolarization. This study investigated the effects of anemia on the frontal QRS-T angle. METHODS: The study included 66 anemic subjects with no cardiac disorders, and 50 age- and gender-matched controls. Twelve-lead electrocardiography (ECG) was obtained for all subjects, and the frontal QRS-T angle was calculated based on the automatic report of the ECG machine. RESULTS: Subjects with anemia had a significantly higher frontal QRS-T angle than subjects without anemia (28.9±14.1 vs. 22.5±11.8, P=0.011). In correlation analysis, the frontal QRS-T angle was positively correlated with the Body Mass Index (BMI; r=0.287, P=0.002), left ventricular mass (LVM; r=0.264, P=0.004), and heart rate (r=0.275, P=0.003) and negatively correlated with the hemoglobin level (r=-0.349, P<0.001). Multivariate regression analysis showed that the hemoglobin level (ß=-0.254, tß=-2.805, P=0.006), BMI (ß=0.240, t=2.770, P=0.007), and LVM (ß=0.201, t=2.303, P=0.023) were independently associated with the frontal QRS-T angle. CONCLUSIONS: The hemoglobin level was found to be an independent predictor of the frontal QRS-T angle.

Evaluation of thiol levels, thiol/disulfide homeostasis and their relation with inflammation in cardiac syndrome X.

OBJECTIVES: Cardiac syndrome X (CSX) is characterized by the presence of myocardial ischemia in the absence of coronary artery stenosis on angiograms. Its relation to oxidative stress and inflammation is well known. There are no data on thiols and their relation with inflammation in CSX. The aim of this study was to investigate thiol levels and thiol/disulfide homeostasis in CSX patients. MATERIALS AND METHODS: Fifty consecutive patients who had documented myocardial ischemia and normal coronary angiogram (CSX group), and 45 age-matched and sex-matched consecutive patients who had normal coronary angiogram without myocardial ischemia (control group) were enrolled in this study. C-reactive protein (CRP), neutrophil/lymphocyte ratio (NLR), native thiol, total thiol, and disulfide levels were measured and disulfide/thiol ratios were calculated in all patients. RESULTS: Demographic, clinical, basic laboratory, and echocardiographic characteristics were similar in the two groups (P>0.05). Serum total thiol, native thiol, and disulfide levels decreased significantly in the CSX group compared with the control group (P<0.001). CRP and NLR increased significantly in the CSX group compared with the control group (P<0.001). Although disulfide/native thiol levels increased in the CSX group, this reduction did not reach statistical significance (5.8 vs. 5.5, P>0.05). The reduction of thiols was correlated negatively with CRP and NLR (P<0.001). Although univariate logistic regression analyses showed that serum total and native thiol levels, CRP and NLR were independent predictors for CSX estimation, stepwise multivariate logistic regression analysis showed only total thiol levels as an independent predictor for CSX (odds ratio=0.966, 95% confidence interval: 0.950-0.982, P<0.001). Also, receiver operating characteristic curve analysis showed that serum total thiol values of 338.4 or below could predict the CSX with 86% sensitivity and 84% specificity (area under curve=0.903; 95% confidence interval: 0.842-0.965). CONCLUSION: Serum total thiol levels decreased significantly in CSX and this reduction independently predicted CSX with strong sensitivity and specificity. This suggests that the reduction in thiols along with increased inflammation may play a pathophysiological role in the development of CSX.

The association of serum prolidase activity with the presence and severity of coronary artery disease.

OBJECTIVES: Prolidase is a cytosolic exopeptidase that cleaves iminodipeptides with carboxy-terminal proline or hydroxyproline and plays major role in collagen turnover. Collagen is the essential content in atherosclerotic plaque playing a key role in the stability/instability of and progression of coronary artery disease (CAD). Consequently, in this study we sought to determine serum prolidase activity and markers of oxidative stress such as lipid hydroperoxide and total free sulfhydryl in CAD. DESIGN AND METHODS: We have evaluated 199 patients with CAD and 122 control cases with clinical, electrocardiographic, and laboratory investigation. We have measured serum prolidase activity and serum total free sulfhydryl levels spectrophotometrically. Serum lipid hydroperoxide levels were determined with ferrous ion oxidation-xylenol orange method. We assessed the association of serum prolidase activity with the presence and severity of CAD and clinical characteristics, and laboratory parameters. RESULTS: Serum prolidase activity (52.5+/-5.6 vs. 46.7+/-5.1 U/l, respectively, P<0.001) and serum lipid hydroperoxide levels were significantly increased in patients with CAD compared with control cases whereas, serum total free sulfhydryl levels were significantly decreased in patients with CAD compared with control cases. Serum prolidase activity and total free sulfhydryl levels were independent predictors of the presence of CAD [(chi=75.532, ss=0.212, P=0.003) and (chi=25.969, ss=-30.486, P=0.019), respectively] and Gensini score [(beta=0.276, P<0.001) and (beta=-0.274, P<0.001), respectively]. Independent predictors of serum prolidase activity were serum high-density lipoprotein cholesterol (beta=-0.138, P=0.023) and urea levels (beta=0.146, P=0.036), and Gensini score (beta=0.317, P<0.001). CONCLUSION: Findings of this study have shown that serum prolidase activity is significantly associated with the presence and severity of CAD, and elevated serum prolidase activity might be an independent predictor of coronary atherosclerosis.