Browsing by Author "Güler, N."

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Aortic Valve Rupture Due To High-Voltage Electrical Injury: Case Report
(2004) Güler, N.; Özkara, C.; Tuncer, M.; Güntekin, Ü.; Kocabas, S.
In the heart, the most common sequelae after electrical injury are myocardial contusion and arrhythmias. A case is presented of segmental ventricular dysfunction and severe aortic regurgitation due to laceration of the right coronary cusp of the aortic valve caused by electrical injury. To the authors' knowledge, this is the first reported case of valvular rupture due to electrical injury. © Copyright by ICR Publishers 2004.
Comparison of Heart Rate Variability and Treadmill Exercise Score in Patients With Stable Coronary Artery Disease
(2001) Eryonucu, B.; Bilge, M.; Güler, N.
Depressed heart rate variability (HRV) is associated with increased mortality and morbidity with various forms of heart disease, and the Duke treadmill score (DTS) provides diagnostic and prognostic information for the evaluation of patients with coronary artery disease (CAD). Our study was aimed at assessing any possible correlation between HRV and DTS in stable CAD. We evaluated the correlation between the HRV assessed by using 24 hour ambulatory ECG monitoring, and treadmill exercise score in 37 patients with angiographically proven and clinically stable CAD. In univariate analysis, DTS showed a significant negative correlation with age (r = -0.89, p < 0.01) and a significant positive correlation with the square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD) (r = 0.67, P < 0.05), percent difference between adjacent normal R-R intervals >50 ms (PNN50) (r = 0.69, P < 0.05), and mean of the standard deviation of all R-R intervals in all the 5-minute intervals (HRVM) (r = 0.63, P < 0.05). There is no significant correlation between DTS and standard deviation of all R-R intervals (SDNN), standard deviation of the averages of R-R intervals in all 5-minute segments of the entire recordings (SDANN) and standard deviation of the SDNN in all the 5-minute intervals (HRVSD). In multiple regression analysis, age was the only independent significant predictor of DTS (p < 0.01). DTS decreased with advancing age. SDNN, SDANN, RMSSD, HRVM and HRVSD were not appearent predictors for detecting of DTS. Age was an independent predictor of DTS. Although DTS was correlated with RMSSD, PNN50 and HRVM in patients with stable CAD, time domain parameters of HRV were not appearent predictor for DTS.
Vasorelaxant Effect of Sildenafil on Aorta and Pulmonary Artery in Rabbits
(2006) Güler, N.; Özbek, H.; Eryonucu, B.
This in vitro study was designed to determine the direct vasorelaxant effect of the sildenafil on isolated rabbit pulmonary artery and compare it with the response of isolated rabbit aorta. Endothelium intact aortic and pulmonary artery rings from seven domestic rabbits were suspended in organ chambers containing 15 mL Krebs solution aerated with 95% O2, 5% CO2. In both phenylephrine and potassium chloride (KCl) precontracted vessels, relaxant responses of sildenafil were recorded by strain gauge transducers connected to a polygraph. Sildenafil (10-9 to 3×10-5 M) induced a dose-dependent vasodilation of phenylephrine precontracted aorta and pulmonary artery; 55 and 95% relaxations were obtained, respectively, at a concentration of 3×10-5 M. Sildenafil also caused a dose-dependent vasodilation of KCl-precontracted aorta and pulmonary artery, but this vasodilation was significantly lesser. Sildenafil-induced relaxations were higher in pulmonary arteries when compared to aortic rings precontracted with either phenylephrine or KCl. We concluded that sildenafil induces a dose-dependent vasodilation on phenylephrine and KCl-precontracted rabbit aorta and pulmonary artery. This vasodilatory effect is more potent in pulmonary arteries than in aortic rings. © 2006 Asian Network for Scientific Information.
Vasorelaxant Effects of Sildenafil and Verapamil on Isolated Rat Aorta With and Without Intact Endothelium
(2006) Özbek, H.; Güler, N.; Eryonucu, B.
This study was designed to compare vasorelaxant effects of the sildenafil and verapamil on isolated rat aorta. Endothelium intact and denuded aortic rings were suspended in organ chambers. Sildenafil (10-10 to 10-4 M) induced a dose-dependent vasodilation of phenylephrine precontracted aortic rings. Relaxation of endothelium intact and denuded aortic rings caused by 10-4 M sildenafil was about 96 and 79%, respectively. Verapamil (10-10 to 10-4 M) induced a dose-dependent vasodilation of phenylephrine precontracted aortic rings. Relaxation of endothelium intact and denuded aortic rings caused by 10-4 M verapamil was about 99 and 98%, respectively. In the phenylephrine precontracted aortic rings, pD2 values for sildenafil were 4.93±0.59 and 4.11±0.62 in the presence and absence of endothelium, respectively. The pD2 values for verapamil were not different in the presence and absence of endothelium (5.15±1.05 vs 4.96±1.14). Verapamil and sildenafil showed a similar degree of vasorelaxant effect in the intact aortic rings, although there was a significant difference in the degree of relaxation in the absence of endothelium (98 vs 79%). Sildenafil induced both endothelium-dependent and independent vasorelaxation on the aortic rings. Although, there was no significant difference in the degree of relaxation induced by verapamil and sildenafil in aortic rings with intact endothelium, verapamil has more relaxing effect in the denuded aortic rings. © 2006 Asian Network for Scientific Information.