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Dive into the research topics where Ferruh Korkut is active.

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Featured researches published by Ferruh Korkut.


American Journal of Cardiology | 2000

Effect of Valsalva maneuver on surface electrocardiographic P-wave dispersion in paroxysmal atrial fibrillation

Tufan Tükek; Vakur Akkaya; Şeref Demirel; Ahmet Bilge Sözen; Hasan Kudat; Dursun Atilgan; Mustafa Özcan; Özen Güven; Ferruh Korkut

The purpose of this study was to investigate the effect of the Valsalva maneuver on P-wave durations and dispersion. After the Valsalva maneuver, we found that maximum P-wave duration increased, minimum P-wave duration decreased, and P-wave dispersion increased in controls, whereas the opposite was true for unselected patients with paroxysmal AF. It was concluded that patients with paroxysmal AF performing the Valsalva maneuver normalized their P-wave dispersion, thereby correcting the inhomogeneous intra-atrial conduction.


International Journal of Cardiology | 2003

Effect of diurnal variability of heart rate on development of arrhythmia in patients with chronic obstructive pulmonary disease

Tufan Tükek; Pinar Yildiz; Dursun Atilgan; Volkan Tuzcu; Mehmet Eren; Osman Erk; Şeref Demirel; Vakur Akkaya; Murat Dilmener; Ferruh Korkut

We examined the possible effect of diurnal variability of heart rate on the development of arrhythmias in patients with chronic obstructive pulmonary disease (COPD). Forty-one COPD patients (M/F: 39/2, mean age: 59+/-8.5 years) and 32 (M/F: 27/5, mean age: 57+/-11 years) healthy controls were included. Twenty-four hour ECG recordings were analyzed for atrial fibrillation (AF) or ventricular premature beats (VPB), and circadian changes in heart rate variability (HRV) were assessed by dividing the 24-h period into day-time (08:00-24:00 h) and night-time (24:00-08:00 h) periods. Night-time total (TP), low frequency (LF) and high frequency (HF) powers were similarly lower from day-time parameters in AF(-) COPD patients (HF 3.91+/-1 vs. 4.43+/-1.04 ms(2), P=0.001) and controls (HF 3.95+/-0.72 vs. 4.82+/-0.66 ms(2), P<0.001). The LF/HF ratios were also significantly reduced in the same patient groups (AF(-) COPD 1.35+/-0.21 vs. 1.27+/-0.19, P=0.04, controls 1.43+/-0.14 vs. 1.24+/-0.09, P<0.001). Night-time TP and LF were increased, HF unchanged and LF/HF significantly increased (1.11+/-0.25 vs. 1.19+/-0.27, P<0.05) in AF(+) COPD patients. Frequency of VPB was correlated with corrected QT dispersion (QTc(d)) (r=0.52, P=0.001) and the day-time/night-time HF ratio (r=0.43, P=0.02). Patients with QTc(d)>or=60 ms did not have the expected increase in night-time HF and had a statistically insignificant increase in LF/HF ratio. In COPD patients with QTc(d)<60 ms, circadian changes in HRV parameters were parallel with the controls. We concluded that COPD patients with arrhythmia had circadian HRV disturbances such as unchanged night-time parasympathetic tone and disturbed sympatho-vagal balance in favor of the sympathetic system all day long, which may explain the increased frequency of arrhythmia.


Journal of The Autonomic Nervous System | 1998

Autonomic dysfunction in vitamin B12 deficiency: a heart rate variability study.

Ahmet Bilge Sözen; Şeref Demirel; Vakur Akkaya; Hasan Kudat; Tufan Tükek; Mustafa Yeneral; Mustafa Özcan; Özen Güven; Ferruh Korkut

This study was arranged to examine whether vitamin B12 deficiency may cause autonomic dysfunction. Time-domain and long-term frequency-domain heart rate variability parameters from 12 patients with pernicious anemia were compared to 12 age and sex matched controls. In B12 deficient patient group time-domain parameters; SDNN (100.4 +/- 37.86 vs. 131.91 +/- 26.94, P = 0.05), SDANN (87.00 +/- 37.77 vs. 118.83 +/- 26.22, P = 0.05) SD (39.41 +/- 13.32 vs. 53.41 +/- 15.39, P = 0.0221), rMSSD (21.41 +/- 10.00 vs. 28.5 +/- 8.42, P = 0.046) were significantly lower when compared to controls. Difference in pNN50 between groups were not statistically significant. In B12 deficient patients frequency-domain parameters; total power (23.08 +/- 9.89 vs. 34.75 +/- 9.56, P = 0.0078), low frequency power (13.5 +/- 6.57 vs. 22.75 +/- 7.25, P = 0.0069) and high frequency power (7.58 +/- 4.25 vs. 11.58 +/- 3.80, P = 0.0175) were significantly lower when compared to controls. It was concluded that B12 deficiency may cause autonomic dysfunction.


Life Sciences | 2002

Effects of losartan on the blood–brain barrier permeability in long-term nitric oxide blockade-induced hypertensive rats

Mutlu Kucuk; Mehmet Kaya; Rivaze Kalayci; Vedat Cimen; Hasan Kudat; Nadir Arican; Imdat Elmas; Ferruh Korkut

Hypertension is closely associated with vascular endothelial dysfunction. The aim of this study was to investigate the effects of Angiotensin II (ANG II) receptor antagonist losartan on the blood-brain barrier (BBB) permeability in L-NAME-induced hypertension and/or in ANG II-induced acute hypertension in normotensive and hypertensive rats. Systolic blood pressure was measured by tail cuff method before, during and following L-NAME treatment (1 g/L). Losartan (3 mg/kg) was given to the animal for five days. Acute hypertension was induced by ANG II (60 microg/kg). Arterial blood pressure was directly measured on the day of the experiment. BBB disruption was quantified according to the extravasation of the albumin-bound Evans blue dye. Losartan significantly reduced the mean arterial blood pressure from 169 +/- 3.9 mmHg to 82 +/- 2.9 mmHg in L-NAME and from 171 +/- 2.9 mmHg to 84 +/- 2.9 in L-NAME plus losartan plus ANG II groups (p < 0.05). The content of Evans blue dye in the cerebral cortex significantly increased in L-NAME (p < 0.01). Moreover, the content of Evans blue dye markedly increased in the cerebellum (p < 0.001) and slightly increased in diencephalon region (p < 0.05) in L-NAME plus ANG II. Losartan reduced the increased BBB permeability to Evans blue dye in L-NAME (p < 0.01) and L-NAME plus ANG II (p < 0.001). These results indicate that L-NAME and L-NAME plus ANG II both lead to an increase in microvascular Evans blue dye efflux to brain, and losartan treatment attenuates this protein-bound dye transport into brain tissue presumably due to its protective effect on endothelial cells of brain vessels.


Journal of The American Society of Echocardiography | 1996

Left ventricular hydatid cyst: An unusual location of Echinococcus granulosus with multiple organ involvement

Dursun Atilgan; Seref Demirel; Vakur Akkaya; Ferruh Korkut

Cardiac Echinococcus is rare but usually associated with fatal complications. An unusual case of cardiac hydatid cyst with multiple organ involvement is presented in which transesophageal echocardiography provided additional information and confirmed transthoracic echocardiographic findings.


International Journal of Cardiology | 2001

Assessment of left atrial appendage function and its relationship to pulmonary venous flow pattern by transesophageal echocardiography.

Tufan Tükek; Dursun Atilgan; Vakur Akkaya; Hasan Kudat; Seref Demirel; Mustafa Özcan; Ferruh Korkut

We evaluated left atrial appendage function and its relationship to pulmonary venous flow in 53 patients divided into four groups. Group 1 consisted of 10 normal subjects. Group 2 included 15 patients with significant pure mitral stenosis in sinus rhythm. In group 3, there were 13 patients with pure significant mitral stenosis and atrial fibrillation. Group 4 consisted of 15 patients with normal mitral valve and atrial fibrilltion. We found significant decrease in left atrial appendage ejection fraction and maximum emptying flow velocity, velocity time integral of systolic pulmonary venous flow in Groups 2, 3 and 4 in comparison with normal subjects. Systolic pulmonary venous flow velocity was significantly decreased in Groups 3 and 4. There was significant correlation between left atrial appendage ejection fraction and peak emptying flow velocity (r = 0.62, P < 0,001). Systolic peak pulmonary venous flow velocity was significantly correlated with left atrial appendage ejection fraction and maximum emptying flow velocity (r = 0.67, P = 0,01; r = 0.58, P < 0,001, respectively). There was also significant correlation between systolic pulmonary venous flow velocity time integral and left atrial appendage ejection fraction (r = 0.66, P = 0.001). When normals were excluded from analysis, all the correlations were still significant. We concluded that left atrial appendage is a contractile structure, and that systolic pulmonary venous flow velocity is influenced by left atrial appendage dysfunction. Therefore left atrial appendage function needs to be considered when interpreting Doppler transmitral and systolic pulmonary venous flow patterns.


Neurorehabilitation and Neural Repair | 1999

Cardiac Dysrhythmias and Autonomic Dysfunction in Chronic Spinal Cord Injury: A 24-Hour Holter Monitoring and Heart Rate Variability Study

Gülçin Demirel; Seref Demirel; Hürriyet Yilmaz; Vakur Akkaya; Dursun Atilgan; Ferruh Korkut

The purpose of this study is to evaluate chronic spinal cord injury (SCI) patients for the incidence of cardiac dysrhythmias and the level of autonomic nervous system (ANS) dysfunction using 24-hour Holter recordings and long-term time-domain and frequency-domain heart rate variability (HRV) analysis. There was no difference be tween groups for the frequency of ventricular or supraventricular ectopics, minimal and mean heart rate, and the longest RR intervals. Maximum heart rate was lower in the quadriplegic group compared with controls (124.1 ± 11.2 vs. 139.4 ± 10.9, p < 0.05). Frequency-domain spectral analysis of high, low, total frequency powers, and ratio LF/HF showed no significant difference between groups. On time-domain analy sis SDANN (94.5 ± 26.4 vs. 131.1 ± 15.1, p < 0.0 1) and SDNN (110.1 ± 29.2 vs. 143.6 ± 19. 1, p < 0.05) were significantly lower in quadriplegics compared with controls. SDANN (74.0 ± 17.9 vs. 115.0 ± 14.2 p < 0.01) and SDNN ( 90.2 ± 21.1 vs. 130.0 ± 22.0 p < 0.05) were significantly lower in complete quadriplegics com pared with incomplete quadriplegics. When the effect of wake (07-22)-sleep (23-07) cycle on frequency-domain parameters were assessed, HF (12.38 ± 5.1 vs. 21.18 ± 8.05, p = 0.001) and TP (35.93 ± 10.5 vs. 45.68 ± 12.68, p = 0.004) showed the physiologic increase during sleep in controls, but was unchanged in quadriplegics (10.48 ± 5.39 vs. 13.35 ± 8.03, p = 0.205 and 30.67 ± 10.61 vs. 37.01 ± 17.59, p = 0.208, respectively). In paraplegics a blunted increase in HF (14.61 ± 7.69 vs. 19.85 ± 14.13, p = 0.09) and TP (38.5 ± 12.77 vs. 47.13 ± 23.08, p = 0.08) was observed. LF showed no significant change in the three groups. Heart rate circadian rhythm was preserved in all three groups (p < 0.01). We concluded that chronic complete cer vical SCI may disrupt modulatory sympathetic flow and downregulates parasympa thetic activity but causes no major arrhythmias needing treatment. Key Words: Chronic spinal cord injury—Cardiac dysrhythmia—Autonomic dysfunction-Heart rate variability.


Current Therapeutic Research-clinical and Experimental | 1997

An open-label, uncontrolled trial of the angiotensin-converting enzyme inhibitor cilazapril in the treatment of patients with chronic congestive heart failure

Seref Demirel; Vakur Akkaya; Cengiz Dinç; Ahmet Bilge Sözen; Gökhan Metin; Hasan Kudat; Mehmet Unal; İlker Yücebir; Tufan Tükek; Ayten Yazici; Mehmet Beyaz; Abidin Kayserilioglu; Ferruh Korkut

Abstract We assessed cilazapril, an angiotensin-converting enzyme (ACE) inhibitor, in the treatment of patients with chronic congestive heart failure. A single 2.5-mg dose of cilazapril was given to 20 patients with chronic congestive heart failure rated as New York Heart Association functional Class II for 15 days according to our protocol. Exercise capacity, breath-by-breath oxygen analysis, and echocardiographic variables were assessed before and after treatment. Cilazapril improved peak exercise time statistically significantly (7.36 ± 3.48 minutes vs 9.45 ± 5.17 minutes), but peak oxygen consumption (17.45 ± 4.19 mL/kg per minute vs 18.65 ± 3.70 mL/kg per minute) and peak heart rate (145.5 ± 23.7 beats/min vs 149.9 ± 27.1 beats/min) did not increase significantly. Anaerobic threshold time (3.31 ± 2.38 minutes vs 4.54 ± 2.99 minutes), anaerobic threshold oxygen consumption (11.03 ± 2.52 mL/kg per minute vs 12.77 ± 2.92 mL/kg per minute), and anaerobic threshold ratio (63.35 ± 7.59% vs 68.10 ± 7.67%) were statistically significant increased with cilazapril treatment without a significant change in anaerobic threshold heart rate (123.3 ± 20.4 beats/min vs 122.1 ± 20.7 beats/min). Cilazapril treatment also decreased statistically significantly the resting heart rate (91.4 ± 20.1 beats/min vs 85.3 ± 17.6 beats/min) during follow-up. No patient decompensated, and diuretic and digoxin doses were not changed during the study. No adverse effects of cilazapril were observed in any patient; however, the effect of cilazapril treatment was not detected on echocardiographic variables. We conclude that the ACE inhibitor cilazapril may be useful in the treatment of patients with chronic congestive heart failure.


Nephrology | 2002

Systolic time intervals in haemodialysis patients with normal ejection fraction: an echocardiographic study

Tufan Tükek; Alaattin Yildiz; Vakur Akkaya; Bilal Görçtin; Mehmet Sukru Sever; Dursun Atilgan; Ferruh Korkut

SUMMARY: In this controlled study, systolic time intervals (STI) and diastolic functions were investigated in haemodialysis patients (HDp) with ejection fraction (EF) within normal limits. Echocardiographic findings in 86 HDp (M:F, 47:39, mean age 36 ± 13 years) and 51 healthy controls (M:F, 22:29, mean age 37±10 years) were compared for STI parameters (projection period (PEP), left ventricular ejection time (LVET) and STI index (PEP/LVET)) and diastolic dysfunction (isovolumetric relaxation time (IVRT) and E/A ratio and deceleration time). the pre‐ejection period (114±21 vs 94±4 msec, P < 0.001) and STI index (0.41 ±0.11 vs 0.34 ±0.02, P < 0.001) were higher in the HDp compared with controls. Increased STI index and prolonged PEP in HDp were independent of left ventricular (LV) hypertrophy and hypertension. Diastolic dysfunction was present in 61% of the patients. the IVRT were also found to be longer in HDp compared with controls (97±16 vs 75±16 msec, P < 0.001), independent of the presence of LV hypertrophy or hypertension. Diastolic dysfunction indicated by IVRT >100 msec and latent systolic dysfunction (STI index >0.4) were randomly distributed, with nearly half (48%) of the patients with prolonged IVRT having an STI index within the normal limits and the other half of the patients with deteriorated STI index having a normal IVRT. the combined systolic and diastolic dysfunction was observed in 30% of the patients. It was concluded that STI indexes deteriorate before an overt systolic dysfunction (normal EF), and that systolic and/or diastolic dysfunction of the myocardium may appear singly or simultaneously because of a common pathogenetic mechanism of myocardial fibrosis.


International Journal of Angiology | 2000

Percutaneous transluminal angioplasty for total coronary occlusion: The effect of restenosis on left ventricular function

Tufan Tükek; Vakur Akkaya; Ahmet Bilge Sözen; Şeref Demirel; Yilmaz Nisanci; Ferruh Korkut

The study was undertaken to evaluate the effect of restenosis on global and regional left ventricular function after percutaneous transluminal coronary angioplasty (PTCA) for total coronary occlusion. Thirty-one consecutive patients with total coronary occlusion treated successfully with PTCA and had follow-up angiography at 3–6 months formed the study group. Nineteen patients had restenosis (16 males, mean age 48±10 years) and 12 had no restenosis (11 males, mean age 53±10 years). In the LAD group there were increases in anterobasal (35.9±8.5% vs 43.1±5.7%, p=0.05) and apical (24.1±6.8% vs 31.7±2.9%, p=0.03) segment motion scores in patients without restenosis after PTCA. Global ejection fractions (63.1±14.5% vs 68.9±12.4%, p=0.09) and anterolateral (28.7±11.3% vs 39.7±10.2%, p=0.09) segment scores increased, but did not reach statistical significance. In the LAD restenosis group anterobasal (41.5±14.3% vs 34.3±12.6%, p=0.001), apical (21.1±15.0% vs 17.8±10.9%, p=0.05) and anterolateral (32.7±19.6% vs 26.6±13.8%, p=0.03) segment motion scores decreased but the decrease in the global ejection fraction (60.3±18.5% vs 58.6±17.4, p=0.38) was not significant. In the RCA+LCX group there was a significant increases in global ejection fraction (69.0±7.5% vs 74.2±7.6%, p=0.03) and posterobasal (23.8±7.8 vs 34.4±8.0, p=0.04) segment motion scores in patients without restenosis. The wall motion scores were unchanged in patients with restenosis in the RCA+LCX group. It was concluded that restenosis after a successful PTCA for total coronary occlusion may deteriorate segmental wall motion and treatment modalities with increased patency rates should be used for total coronary occlusions.

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