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    Effects of coronary revascularization and concomitant aneurysmectomy on QT interval duration and dispersion
    (Churchill Livingstone Inc Medical Publishers, 2006) Kosar, F; Nisanoglu, V; Aksoy, Y; Colak, C; Erdil, N; Battaloglu, B
    A reduction in QT dispersion (QTd) has been previously shown in patients receiving thrombolytics and undergoing coronary artery bypass grafting (CABG). The purpose of the present study was to investigate changes occurring in corrected QT intervals or QT dispersion after CABG and concomitant aneurysmectomy in the same session. The study population included 43 patients with coronary artery disease with left ventricular aneurysm (LVA). The control group included 32 patients with coronary artery disease without LVA. The study patients underwent CABG and aneurysmectomy in the same surgical session. Corrected maximum and minimum QT interval duration (QTcmax and QTcmm) and corrected QT dispersion (QTcd) were measured in the study patients before and after surgery. QTcmax and QTcd in the patients with LVA were significantly higher than in the patients without LVA (P < .001 and P < .001, respectively). QTcmax and QTcd in the patients with LVA were significantly shortened after surgery (P < .001 and P < .001, respectively). This study showed that QTcmax and QTcd values are significantly reduced after CABG and concomitant aneurysmectomy. We have suggested that coronary revascularization and left ventricular reconstruction in the same session have beneficial effects on QT interval duration and dispersion. (c) 2006 Elsevier Inc All rights reserved.
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    Identifying risk factors in a mostly overweight patient population with coronary artery disease
    (Westminster Publ Inc, 2003) Yologlu, S; Sezgin, AT; Ozdemir, R; Sezgin, N; Colak, C; Topal, E; Barutcu, I
    Overweight/obesity is a complex multifactorial chronic disorder, and the American Heart Association (ANA) has recently classified as a modifiable risk factor for coronary heart disease (CAD). This study (1) evaluates the association between CAD in a patient population mostly overweight (MOP) and conventional and novel coronary risk factors by using univariate and multivariate logistic regression analysis and (2) seeks to find the best model by comparing univariate and multivariate logistic regression analysis algorithms, which were systematically applied to risk factors by using Hosmer-Lemeshow statistic test. In univariate analysis, there were significant associations between CAD in MOP and conventional and novel risk factors. However, the model's sensitivity, specificity, and accuracy levels were weak. In multivariate analysis, although some risk factors were not found as predictors of coronary artery disease, the model showed good fit to data and had high sensitivity, specificity, and accuracy levels. This was also confirmed by using the Hosmer-Lemeshow goodness of fit test, more specifically.
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    Selective endothelin a (ETA) receptor antagonist (BQ-123) reduces both myocardial infarct size and oxidant injury
    (Elsevier Ireland Ltd, 2006) Ozdemir, R; Parlakpinar, H; Polat, A; Colak, C; Ermis, N; Acet, A
    Objective: Endothelins (ET) can be considered stress-responsive regulators working in paracrine and autocrine fashion. It has been suggested that elevated levels of ET may be responsible for the low coronary re-flow phenomena. Ischemia-reperfusion (I/R) was shown to stimulate ET release in rat heart; however, the mechanism(s) of this effect has not been clarified. Therefore, this study was focused to investigate the effect of BQ-123, selective ETA receptor antagonist, on three aspects of myocardial ischemia-reperfusion (MI/R) injury: hemodynamic parameters, infarct size and oxidant-antioxidant status in the absence and presence of ET-1 in an vivo rat model. Methods and results: To produce MI/R, a branch of the descending left coronary artery was occluded for 30 min followed by 2 h reperfusion. ECG changes, blood pressure (BP), and heart rate (HR) were measured before occlusion and continued both occlusion and reperfusion. Forty rats were randomly assigned to five groups equally: (1) sham-operated rats without coronary ligation, (2) I/R group, (3) I/R + BQ-123-treated group (10 mu g/kg/min i.v.), (4) I/R + ET-treated group (25 ng/kg/min i.v.), (5) I/R + ET + BQ-123-treated group. The results are expressed as mean +/- S.E.M. In the ET-1 plus I/R group, the ratio between the infarcted area and area at risk 56 +/- 1% was significantly higher than I/R group (49 +/- 1%). In the BQ-123 group with or without exogenous ET-1 treatment in I/R group, this ratio was significantly lower at 40 +/- 2 and 37 +/- 1%, respectively. As compared to sham group, I/R increased lipid peroxidation whereas decreased nitric oxide (NO), glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) contents. This decreased antioxidant enzymatic defense could result in aggravated oxidative damage in I/R group rat hearts. ET-1 administration group showed severe oxidative damage. BQ-123 administrations to I/R group with or without ET-1 caused significantly decrease in lipid peroxidation and increased in SOD, CAT activities and NO generation and GSH content when compared with I/R group alone. Conclusions: The most important finding of the present study is that the ET blockade reduced I/R-induced myocardial injury. The mechanism of this reduction was speculated to be a resistance to ischemic injury in the subcellular levels of the myocardium conferred by a reduction of vascular constriction and improvement of imbalance in the antioxidant status. (c) 2005 Elsevier Ireland Ltd. All rights reserved.