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Biomedical subjects

Mehmet Uzun

Publications and source records attributed to Mehmet Uzun.

At least 19 recordsLinked to original sources
PubMed2006

Bisoprolol improves echocardiographic parameters of left ventricular diastolic function in patients with systemic hypertension.

Left ventricular (LV) diastolic dysfunction (LVD) is a common complication secondary to hypertension. It has been reported that bisoprolol is effective in reducing blood pressure and has beneficial cardiac effects in patients with hypertension. However, its effect on LV diastolic function has not been studied in detail. In this study, we sought to determine bisoprolol's effect on left ventricle diastolic function. Data from 25 patients were statistically analyzed. Peaks E and A wave, E/A ratio, isovolumetric relaxation time and E wave deceleration time were measured echocardiographically. Doppler echocardiography measurements after bisoprolol treatment revealed an improvement in LV diastolic function. In conclusion, our results show that treatment with bisoprolol, improves echocardiographic parameters of LV diastolic function after 3 months of treatment.

Antihypertensive Agents↗
PubMed2006

[The value of augmentation index and myocardial performance index obtained from cardiac catheterization pressure recordings in predicting coronary artery disease].

OBJECTIVE: The aim of the study was to determine the relation between some parameters, which can be obtained from cardiac catheterization pressure records, and coronary artery disease. METHODS: The study included 65 patients, in whom coronary angiography was performed by the cardiologists of the study. The parameters could be obtained in 40 patients (59+/-6 years; 28 male), and statistical analysis included the data of these patients. From the pressure recordings, myocardial performance index (MPI), isovolumetric relaxation time (IVRT), isovolumetric contraction time (IVCT), ejection time (ET), augmentation wave amplitude (AW), augmentation wave time (AWT) and augmentation index (AI) were measured manually. Coronary artery disease was defined as the presence of any lesion, without regarding the degree of narrowing. The parameters were evaluated with respect to relation with presence of coronary artery disease (Mann-Whitney U test), relation with risk factors for atherosclerosis (Mann-Whitney U test and Chi square test) and capability of predicting coronary artery disease (area under ROC curve, AUC). Statistical significance was set at 0.05. RESULTS: The presence of coronary artery was significantly related to AI, AWT, AW, IVCT and MPI (p<0.001 for all). The most sensitive parameters for coronary artery disease were AI (sensitivity 94%, AUC -0.846, p<0.001) and AW (sensitivity 94%, AUC -0.848, p<0.001), while the most specific one was AWT (specificity 82%, AUC -0.833, p<0.001). The MPI and IVCT were weakly related with risk factors, while IVRT had stronger relation. The parameters of augmentation wave were significantly related with high density lipoprotein cholesterol, whereas the relation with low density lipoprotein cholesterol was weak. CONCLUSION: The parameters, which are obtained from cardiac catheterization pressure recordings, are related with coronary artery disease. They may be useful for predicting future coronary artery disease especially in patients with normal coronary angiogram. It is useful to add these parameters into the reports of coronary angiograms.

Cardiac Catheterization↗
PubMed2006

[Relationship between coronary risk calculation and distribution of the coronary artery lesions and risk factors].

OBJECTIVES: Early diagnosis and treatment of coronary artery disease is gaining more importance because of its increasing incidence. The calculation of coronary risk score is one of the most important approaches. The aim of the study is to find out the relation between coronary risk score and vessel distribution of the coronary heart disease. METHODS: The study included 49 patients (mean age = 63+/-8 years; 36 males) whose coronary disease was proven by coronary angiography. The severity of the disease is established according to the number of the vessels with >50% stenosis. RESULTS: According to the results; age (p=0.548), gender (p=0.116), uric acid (p=0.091), and smoking (p=0.718) are not effective on diseased vessel distribution. Similarly, total coronary risk score and vessel involvement was not correlated (p=0.115). The ten year coronary risk and vessel involvement was not in good correlation, too (p=0.523). Low-density lipoprotein (LDL)-cholesterol levels were lower in patients with multiple vessel disease but the statistical significance was borderline (p=0.051). High-density lipoprotein (HDL)-cholesterol levels were lower in multiple vessel disease (p=0.004). Both LDL-cholesterol and HDL-cholesterol scores were decreasing with increased number of involved vessels (p=0.035, p=0.001). Multivariate analysis revealed that blood pressure score, and HDL cholesterol score were directly related and LDL-score were inversely related to the number of the involved vessels. The height and vessel involvement was also in good correlation (p=0.024). CONCLUSION: The LDL-cholesterol, HDL-cholesterol, diastolic blood pressure and height are affective on the number of the involved vessels. The total coronary risk scores are not correlated with the severity and distribution of the disease.

Aged↗
PubMed2005

The prevention of myocardial ultrastructural changes by perindopril, atenolol and amlodipine in chronic alcohol administered rats.

The effects of perindopril, an angiotensin converting enzyme inhibitor, atenolol, a beta adrenergic receptor blocker and amlodipine, a calcium channel blocker were investigated in chronic alcohol administered rats. Adult male Wistar rats (240-320 g) were used in the present study. Alcohol was given to rats by a modified liquid diet for 21 days. Perindopril (2.5 and 5 mgkg(-1)), atenolol (5 and 10 mg kg(-1)) and amlodipine (5 and 10 mg kg(-1)) were injected to rats in different groups intraperitoneally for 21 days. Control rats were pair fed by an isocaloric liquid diet containing sucrose as a caloric substitute for alcohol. Saline was injected to control rats for 21 days. Rats were anesthetized with ether. Their hearts were removed and 1 mm3 samples from left ventricles were fixed. Five fields per heart were examined and photographed with transmission electron microscope. Blood alcohol levels were also measured spectrophotometrically. Daily alcohol consumption of the rats was in a range of 12.09-15.5 g kg(-1). Blood alcohol concentrations were found as 145.63 mg dl(-1) at 21st day of alcohol consumption. Chronic alcohol consumption caused some marked myocardial injuries. Perindopril and atenolol but not amlodipine produced some significant beneficial effects on alcohol-induced myocardial damages. Our results imply that perindopril and atenolol but not amlodipine have protective effects on heavy chronic alcohol consumption-induced myocardial injury in rats.

Adrenergic beta-Antagonists↗
PubMed2005

Left atrial functions after myocardial infarction.

Acute myocardial infarction results in not only left ventricular but also left atrial dysfunction. Left atrial function is important for optimal filling of the left ventricle. In this study, we aimed at evaluating left atrial functions 6 months after acute myocardial infarction in three different patient groups (thrombolytic therapy, primary percutaneous intervention, or no reperfusion strategies). Between October 2002 and May 2003, 48 patients with ST elevation myocardial infarction who were either administered thrombolytic therapy (group T, n=16), underwent primary angioplasty (group A, n=20), or underwent no reperfusion therapy (group C, n=12) at our unit were enrolled into the study. Echocardiography was performed in these patients 6 months after acute myocardial infarction. Left atrial contractility was assessed by atrial ejection force. Left atrial contribution was assessed by atrial fractional shortening and left atrial volume was calculated. The left atrial volume was significantly higher in group C (P<0.05), but there was no significant difference between groups A and T (P>0.05). Patients in group C had significantly lower atrial ejection force values compared with the other groups (P<0.05). Atrial fractional shortening was not significantly different among the three groups (P>0.05). Atrial ejection force, which is an indicator of left atrial contractility, is better with either angioplasty or thrombolysis. Left atrial volume is higher in patients who were not treated with reperfusion strategies. Further studies are needed to explain the mechanism involved.

Aged↗
PubMed2005

Univentricular heart and supramitral ring: an unusual association.

Univentricular heart, which is rarely seen cardiac anomaly, is associated with various cardiac anomalies. The presence of supramitral ring and univentricular heart in the same patient is very interesting association which, to the best of our knowledge, was not reported previously.

Abnormalities, Multiple↗
PubMed2005

A simple different method to use proximal isovelocity surface area (PISA) for measuring mitral valve area.

BACKGROUND: Angle-correction is an important limiting factor for using proximal isovelocity surface area (PISA) method in measuring mitral valve area (MVA). In this study, we derived a novel formula, which simplifies the angle-correction, and tested its use in patients with mitral stenosis (MS). METHODS: The study included 30 MS patients without concomitant aortic or mitral regurgitation. We used mathematical equations and established a relation between the angle and its corresponding border, 'a', by using linear regression analysis. It was found that MVA is equal to [(1.11*a2 + 0.95)* r2 (Val/Vmax)]. We compared this formula with plain angle-corrected and solid angle-corrected PISA methods, planimetry (reference method) and pressure-half time method by linear regression analysis. RESULTS: All methods were in significant relation with the reference method, two-dimensional planimetry. We found that there is a good relation between our method and planimetry (r = 0.79, p < 0.001), pressure half-time method (r = 0.85, p < 0.001), angle-corrected PISA method (r = 0.99, p < 0.001), and solid angle-corrected PISA method (r = 0.88, p < 0.001). The time duration of the new method was shorter (p < 0.001). CONCLUSION: Our method is an easy way for applying angle-corrected PISA method to mitral valve area measurement in patients with mitral stenosis. Absence of the need for estimating the angle is the major advantage.

Adult↗
PubMed2005

Testosterone relaxes human internal mammary artery in vitro.

Preliminary clinical studies of testosterone therapy in male patients with coronary artery disease raised promising results. However, there is no study on in vitro effects of testosterone in human isolated arteries. We investigated the effect of testosterone on contractile tone of human isolated internal mammary artery. The responses in human internal mammary artery (IMA) were recorded isometrically by a force-displacement transducer in isolated organ baths. Testosterone (10 nM to 100 microM) was added cumulatively to organ baths either at rest or after precontraction with KCl (68 mM) and PGF2alpha (10 microM). Testosterone-induced relaxations were tested in the presence of cyclooxygenase inhibitor indomethacin (10 microM), nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME, 1 microM), nonselective large-conductance Ca2+-activated and voltage-sensitive K+ channel inhibitor tetraethylammonium (TEA, 1 mM), ATP-sensitive K+ channel inhibitor glibenclamide (GLI, 100 microM), and voltage-sensitive K+ channel inhibitor 4-aminopyridine (4-AP, 1 mM). Testosterone produced relaxation in human IMA (Emax 33% and 41% of KCl- and PGF2alpha-induced contraction, respectively). Vehicle had no significant relaxant effect. Except for TEA, the relaxation at low concentrations is not affected by either K+ channel inhibitors (GLI and 4-AP) or L-NAME and indomethacin. We report for the first time that supraphysiological concentrations of testosterone induce relaxation in IMA. This response may occur in part via large-conductance Ca2+-activated K+ channel-opening action.

Humans↗
PubMed2005

A giant dissecting aneurysm of ascending aorta.

Aortic aneurysm is a serious clinical challenge for the cardiologist. Aneurysm expansion frequently associated with significant dissection and rupture risk. Currently available diagnostic modalities make earlier diagnosis and therapy possible hence giant aneurysm with dissection is relatively rare. In this case report, we present a patient with giant aortic aneurysm with dissection.

Aortic Dissection↗
PubMed2005

Detection of the defibrillation threshold using the upper limit of vulnerability following defibrillator implantation.

OBJECTIVE: This study was designed to test defibrillation threshold (DFT) with the least number of fibrillation inductions using upper limit of vulnerability (ULV) and to describe the most practical set of ICD during DFT following implantation. BACKGROUND: Although the correlation between ULV and DFT has been well described, there has been no uniform DFT testing protocol taking the advantage of ULV after defibrillator (ICD) implantation. METHODS: A total of 26 patients undergoing a new ICD implantation had a DFT induced with scanned T wave shock. The hypothesis that ventricular fibrillation (VF) could be defibrillated with 5 J higher than the highest T wave shock needed to induce VF or with 10 J if the T wave shock needed to induce VF was less than 5 J, was tested and 20 patients fulfilled these criteria. The methodology is improved by detecting peak T wave with 12-lead ECG, applying biphasic T wave shock and scanning the T wave shock in a wider window. RESULTS: Five patients in the first group (n = 15) and one patient in the second group (n = 11) did not fulfill the above hypothesis. The common features of six patients who did not fulfill the hypothesis were that T wave shock needed to induce VF was either under 5 J (5 patients) or high (1 patient). CONCLUSION: This study revealed the importance of methodology in studies regarding ULV and DFT. Following ICD implantation, we propose the first biphasic T wave detected by 12-lead ECG and rescue shock set at 10 and 15 J, respectively. If any of the scanned T wave (40 ms before and 40 ms after the peak T wave with decrements and increments of 20 ms) shocks could not induce VF, then the T wave and the first rescue shock should be set at 5 and 10 J, respectively. If the induction of VF has been unsuccessful with T wave shock at 5 J, then a safe defibrillation with 10 J should be expected in majority.

Adult↗
PubMed2005

Elongation index as a new index determining the severity of left ventricular systolic dysfunction and mitral regurgitation in patients with congestive heart failure.

The shape of the left ventricle is an important echocardiographic feature of left ventricular dysfunction. Progression of the mitral regurgitation and consequent left ventricular remodeling is unpredictable in heart failure. Elongation index is an index of left ventricular sphericity. The surface area of the elongated ventricle is larger than that of a spherical one. The objective of this study was to assess the relation between elongation index and the degree of mitral regurgitation along with noninvasive indices of left ventricular function. Thirty-two patients (21 male, 11 female, mean age: 57 +/- 6 yrs) with congestive heart failure and mitral regurgitation were included. Patients were stratified into three groups according to vena contracta width as having mild (n = 11), moderate (n = 11) and severe mitral regurgitation (n = 10). The elongation index (EI) was considered as equal to {[(left ventricular internal area-measured) - (theoretical area of the sphere with measured left ventricular volume)]/(theoretical area of the sphere with measured left ventricular volume)}. Ejection fractions by the modified Simpson rule, dP/dt and sphericity index (SI) were also recorded. The relationship between (EI), ejection fraction, dP/dt and SI reached modest statistical significance (p < 0.05). When the EI and SI were compared, the correlation was also significant (p < 0.01). The areas under the receiver operator curve of EI and SI for discriminating dP/dt < 1000 mm Hg/s were 0.833 and 0.733, respectively. In conclusion, the elongation, which defines the shape of the left ventricle, might be related to the systolic function of the left ventricle and the degree of the mitral regurgitation. Further studies are needed to demonstrate its use in other clinical entities.

Adult↗
PubMed2005

The effect of tirofiban and clopidogrel pretreatment on outcome of old saphenous vein graft stenting in patients with acute coronary syndromes.

In spite of developments in interventional cardiology, the success rate of saphenous vein graft stenting is still low in patients with acute coronary syndromes. In this study, we aimed at finding out the effect of pretreatment with Tirofiban, a glycoprotein IIb/IIIa inhibitor, and clopidogrel, an adenosine diphosphate antagonist, on the outcome of saphenous vein graft stenting in patients with acute coronary syndrome. A total of 47 patients, who had lesions in saphenous vein grafts and acute coronary syndrome, could be randomized to treated group (n = 24), who received Tirofiban and clopidogrel for 48 hours before the intervention, and untreated group (n = 23), who did not receive Tirofiban and clopidogrel. In the untreated group, the intervention was performed just after the coronary angiography. All patients underwent stenting as the standard intervention. The groups were compared by Mann-Whitney's U-test or Chi-Square test. The level of statistical significance was set at 0.05. There were no significant differences regarding age, gender, and atherosclerotic risk factors between the two groups. In treated group, precutaneous coronary intervention was successful in all patients and no-reflow phenomenon occurred in only one patient. The rate of no-reflow or slow-flow phenomenon was significantly lower in treated group (one patient vs 9 patients, p = 0.004). One patient in untreated group experienced ventricular fibrillation, which was converted to sinus rhythm after defibrillation. During short-term follow-up, there were no acute myocardial infarction, coronary bypass surgery or death in both groups. There was no major bleeding. Minor bleeding was more frequent in treated group, but it did not achieve statistical significance (3 vs 1; p = 0.322). In conclusion, pretreatment with tirofiban and clopidogrel before percutaneous coronary intervention might result in better immediate outcomes in old saphenous vein grafts without any significant increase in bleeding complications.

Acute Disease↗
PubMed2005

Chronic heavy ethanol consumption is associated with decreased platelet aggregation in rats.

Although moderate alcohol consumption seems to be protective against atherosclerosis, coronary artery disease rate increases with its higher doses. Platelet aggregation is an important process which contributes to the atherosclerosis. The aim of this study was to determine whether heavy ethanol consumption stimulates or inhibits platelet aggregation. Fourteen adult male Wistar rats were used. Ethanol (7.2%, v/v) in a modified liquid diet was given to eight rats for 21 days, which mimicked characteristics similar to human chronic alcoholism. Six rats constituted the control group. Adenosine diphophate (ADP) and collagen-induced platelet aggregation was measured in whole blood. We found reduced ADP-induced mean maximal aggregation in the alcoholic rat group compared to the control group at dose of 5 microM (p < 0.005). We also found decreased platelet aggregation responses to collagen in the alcoholic group (p < 0.006 for 2 microg/ml collagen, and p < 0.05 for 5 microg/ml collagen). In conclusion, chronic heavy ethanol consumption results in the decreased platelet aggregation in a rat model of alcoholism. Therefore, increased mortality from coronary artery disease in chronic alcoholism may be explained by other factors such as dietary imbalances and coexisting conditions, which include hypertension and depression.

Adenosine Diphosphate↗