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Biomedical subjects

G Kabakci

Publications and source records attributed to G Kabakci.

At least 19 recordsLinked to original sources
PubMed2001

No evidence of cardiac autonomic involvement in ankylosing spondylitis, as assessed by heart rate variability.

The aim of this study was to investigate the involvement of autonomic nervous system (ANS) function by using power spectral analysis of heart rate variability (HRV) method in patients with ankylosing spondylitis (AS). The study included 94 AS patients all fulfilling the New York criteria for AS, and 49 healthy volunteers. Recordings for HRV were obtained with a PC-based high-resolution electrocardiographic system and analysed using power spectral analysis. The peak around 0.04-0.15 Hz was defined as low-frequency peak (LF) and the other, around 0. 15-0.40 Hz, was defined as high-frequency peak (HF), representing mostly the sympathetic and the parasympathetic components of the ANS, respectively. The following variables were calculated and compared between groups: the LF in absolute and normalised units (LF nU); the HF in absolute and normalised units (HF nU); and LF/HF ratio. The AS group included 47 male and 47 female subjects with a mean age of 33 +/- 11 years (range 16-64). In the control group there were 23 male and 26 female healthy subjects (mean age 33 +/- 8; range 19-60). None of the patients or control subjects had any cardiac or neurological symptoms. Both groups were similar with respect to age and sex characteristics (p > 0.05). The HRV analysis indicated that the peaks of LF, LF nU, HF, HF nU and LF/HF ratio were similar in both groups. Groups also did not differ with respect to heart rate at the time of examination. Our data demonstrated no evidence of ANS involvement as assessed by HRV analysis in AS patients.

Adolescent↗
PubMed2001

Hormone replacement therapy to improve left ventricular diastolic functions in healthy postmenopausal women.

OBJECTIVES: To investigate the effects of estrogen and estrogen plus progesterone replacement therapy on left ventricular systolic and diastolic function parameters in healthy postmenopausal women. METHODS: Forty-six healthy consecutive postmenopausal women were prospectively enrolled. Hormone replacement therapy (HRT), which was either 0.625 mg/day conjugated equine estrogen (CEE) alone, or with 2.5 mg/day medroxyprogesterone acetate (MPA) was administered depending on the hysterectomy status. Left ventricular systolic and diastolic function parameters were evaluated with echocardiography before and after 6 months of HRT. The paired t-test was used for statistical analysis. RESULTS: Estrogen or estrogen plus progesterone did not significantly alter the left ventricular dimensions and systolic function parameters. However, significant improvements were noted in several diastolic function parameters including late diastolic mitral flow velocity, ratio of early to late mitral flow velocity and isovolumic relaxation time (P=0.003, P=0.001 and P=0.005, respectively, for the CEE group; all P<0.001 for the CEE+MPA group). CONCLUSIONS: Estrogen or estrogen plus progesterone replacement therapy may significantly improve left ventricular diastolic functions in healthy postmenopausal women.

Blood Pressure↗
PubMed2001

The diagnostic value of 12-lead electrocardiogram in predicting infarct-related artery and right ventricular involvement in acute inferior myocardial infarction.

BACKGROUND: The aim of the present study was to investigate the predictive value of presentation and 24-hour electrocardiograms in defining the infarct-related artery (IRA), its lesion segment, and the right ventricular involvement in acute inferior myocardial infarction (MI). METHODS: One hundred forty-nine patients with acute inferior MI were included. Infarct-related artery, its lesion segment, and the validity of new ECG criteria for the diagnosis of right ventricular MI (RVMI) were investigated by means of criteria obtained from admission and 24- hour ECGs. RESULTS: The presence of ST-segment elevation in lead III > lead II criterion (Criterion 1) and ST-segment depression in lead I > lead aVL criterion (Criterion 2) from admission ECG defined the right coronary artery (RCA) as IRA with a sensitivity of 64% and a specificity of 100%. These two criteria also defined the proximal or mid lesions in RCA as culprit lesions (sensitivity of 99%, specificity of 96%). Absence of these two criteria indicated Cx as IRA with a sensitivity of 50% and a specificity of 97%. The depth of Q wave in lead III > lead II criterion (Criterion 3) had no value for discrimination of IRA, but the width of Q wave in lead III > lead II criterion (Criterion 4) supported the RCA to be IRA with a sensitivity of 60% and a specificity of 61% (Criteria 3 and 4 were obtained from 24-hour ECGs). The finding of Criterion 1 plus Criterion 5 (ST elevation in V(1) but no ST elevation in V2) on admission ECG had a sensitivity of 63% and a specificity of 99% in the diagnosis of RVMI. CONCLUSION: We concluded that 12-lead ECG is a cheap, easy, and readily obtainable diagnostic approach in discrimination of IRA and its culprit lesion segment. However, despite high specificity, due to moderate degree sensitivity, its value for the diagnosis of RVMI is questionable.

Adult↗
PubMed2001

Effects of hormone replacement therapy on heart rate variability in postmenopausal women.

BACKGROUND: Hormone replacement therapy (HRT) is associated with reduced cardiovascular risk, but the underlying mechanism(s) are not fully understood. This study investigated the effects of a 6-month course of HRT on cardiac autonomic function parameters assessed by heart rate variability (HRV) in postmenopausal women. METHODS: Forty-six healthy postmenopausal women (age 48 +/- 5, range 40-60) with normal baseline electrocardiogram and negative exercise testing were enrolled. HRT, which was either 0.625 mg/day conjugated equine estrogen (CEE) plus 2.5 mg/day medroxyprogesterone acetate or 0.625 mg/day CEE alone were administered depending on hysterectomy status. Power spectral analysis of HRV was performed to calculate the low frequency component in absolute (LF) and normalized units (LF nu), high frequency component in absolute (HF), and normalized units (HF nu), and the LF/HF ratio. The standard deviation of RR intervals (SDNN) was calculated from the time series of RR intervals. RESULTS: A 6-month course of HRT did not significantly alter resting heart rate (P > 0.05). The LF/HF ratio and LF nu significantly decreased after HRT (P = 0.022 and P = 0.032), whereas a significant increase was noted in the HF component of HRV (P = 0.043), indicating an improvement in cardiac autonomic function. The SDNN value, which was 28.8 +/- 11.8 ms before HRT significantly increased to 35.4 +/- 16.7 ms after 6 months (P = 0.011). CONCLUSION: Our results indicate that a 6-month course of HRT may significantly improve cardiac autonomic function parameters, a finding that could at least partly explain the potential cardioprotective effect(s) of HRT.

Adult↗
PubMed2001

Left ventricular septal aneurysm in association with bicuspid aortic valve--a case report.

Diverticula of the left ventricle are rare cardiac anomalies. Most cases arise from the apex of the left ventricle and are usually found in children. Only a few cases have been documented in adults. The authors report a case of a 38-year-old woman who presented with dyspnea and chest pain. She was found to have a septal left ventricular diverticulum associated with bicuspid aortic valve, aortic stenosis, and aortic regurgitation. The aortic valve was replaced with the resection of the diverticulum. Pathologic examination confirmed the diagnosis of fibrous diverticulum.

Adult↗
PubMed2001

A huge mitral valve tumor and its vascularity--a case report.

Primary cardiac tumors of the mitral valve are extremely rare; however, they present a major risk of embolization. Therefore, prompt diagnosis and urgent treatment is obligatory. The authors report the case of a 60-year-old man with a huge mitral valve mass and its vascularity, which was diagnosed by transthoracic echocardiography and selective coronary arteriography. Our patient's mitral valve tumor had a size of 5.9 x 2.9 cm, which was the largest size reported up to this time in this location. The patient died from a major cerebrovascular event before surgical excision could be performed.

Fatal Outcome↗
PubMed2001

What is the optimal evaluation time of the QT dispersion after acute myocardial infarction for the risk stratification?

The sequential changes of the corrected QT dispersion (QTcD) were studied in 136 patients 1 day to 30 days after a transmural acute myocardial infarction (AMI) to investigate the optimal measurement time of QT dispersion for risk stratification. The study group included 136 patients (89 men; mean age, 57+/-10 years) with transmural AMI who were treated with thrombolytics (Tr+ group, n = 73) or not (Tr- group, n = 63) and 65 healthy controls (43 men; mean age, 56+/-7 years). Fourteen patients in whom ventricular tachycardia (VT), ventricular fibrillation (VF), or sudden cardiac death developed during the 30-day period were also evaluated as major cardiac arrhythmia (MCA) group. ECGs were obtained for each patient on days 1, 3, 5, 10, 15, and 30 after AMI. QTc dispersion in patients with AMI (for every period of QTcD after MI) was significantly more prolonged than in normal controls (49.3+/-16.3 ms) (p<0.001). QTcD was significantly greater in patients without thrombolytics than in patients with thrombolytics for every period (days 1, 3, 5, 10, 15, and 30) of QTcD after MI (p<0.001). The mean of QTcD was significantly greater in patients with MCA than in patients without MCA group for every period (days 1, 3, 5, 10, 15, and 30) of QTcD after MI (p < 0.05). Maximal QTcD was seen on day 10 (p < 0.05 1st vs day 10 for each group) after myocardial infarction, and then reached a plateau for an each group. The ideal time to measure the QTD for risk stratification is at least 10 days after AMI.

Death↗
PubMed2001

Extent of coronary atherosclerosis and homocysteine affect endothelial markers.

The aim of the study was to evaluate the effects of the presence, extent, and clinical stability of coronary artery disease on endothelial function parameters, C-reactive protein and homocysteine levels. Fifty-eight patients with angiographically documented coronary artery disease and 25 patients with normal coronary arteries were evaluated for risk factors, plasma homocysteine, C-reactive protein, and soluble adhesion molecule levels. Vascular cell adhesion molecule-1 and sE-selectin were significantly higher in the group with coronary artery disease than in healthy subjects (p = 0.005 and p = 0.031, respectively). Patients with unstable angina had significantly higher C-reactive protein (p < 0.001), troponin I (p < 0.01), and leukocyte counts (p < 0.05) than those with stable angina. sE-selectin levels were correlated with the extent of coronary atherosclerosis (r = 0.444, p < 0.05), and plasma homocysteine levels were associated with vascular cell adhesion molecule-1 (r = 0.479, p < 0.05) in unstable cases. These results suggest that vascular cell adhesion molecule-1 and sE-selectin are useful for determining the presence of coronary atherosclerosis, whereas C-reactive protein, troponin 1, and leukocyte count are predictors of clinical stability.

Angina, Unstable↗
PubMed2000

Plasma big-endothelin levels, cardiac autonomic neuropathy, and cardiac functions in patients with insulin-dependent diabetes mellitus.

BACKGROUND: The alteration of endothelin (ET) levels in diabetic patients with cardiac autonomic neuropathy (CAN) has not been studied extensively and its correlation with cardiac function parameters has not been discussed. HYPOTHESIS: The aim of the present study was to discuss the correlation between the degree of cardiac autonomic neuropathy, plasma big-ET levels, and cardiac functions in diabetic patients who were clinically free of cardiovascular disease. METHODS: Twenty subjects (32.1 +/- 7.8 years, 11 men, 9 women) with insulin-dependent diabetes mellitus (IDDM) were studied to evaluate the relationship between circulating big-endothelin (big-ET1) levels, CAN, and cardiac functions. The severity of CAN was scored according to Ewing's criteria. Cardiac functions were assessed using Doppler echocardiography. RESULTS: Left ventricular systolic function in the patient group was within normal limits and comparable with the values of the control group (n = 10). The mean E/A values of diabetics with CAN (1.15 +/- 0.33, p = 0.004) and without CAN (1.34 +/- 0.17) were significantly lower than those of controls (1.57 +/- 0.27). Diabetics with CAN had significantly higher big-ET1 values (81.1 +/- 94 pg/ml) compared with others (12.4 +/- 5.9 and 21.1 +/- 17.7 pg/ml, p = 0.04). Circulating big-ET1 levels showed a significant correlation with E/A values in the control group (p = 0.01, r = -0.7) and with peak A values (p = 0.003, r = 0.64) in diabetics. The CAN score correlated negatively with E/A values (p = 0.01, r = 0.54). CONCLUSIONS: High big-ET levels might have an important role in the pathogenesis or consequences of diastolic dysfunction in diabetics with CAN. Their role in cardiac autonomic neuropathy and diastolic dysfunction should be investigated further.

Adult↗
PubMed2000

Is ventricular repolarization heterogeneity a cause of serious ventricular tachyarrhythmias in aortic valve stenosis?

BACKGROUND: It is well known that there is a close relation between sudden cardiac death and serious ventricular tachyarrhythmias in patients with aortic valve stenosis (AS). QT dispersion (QTd) reflects the ventricular repolarization heterogeneity and has been proposed as an indicator for ventricular arrhythmias. HYPOTHESIS: This study investigated the QTd and its relevance to the clinical and echocardiographic variables. METHODS: In all, 51 patients (33 men, 18 women, mean age 56 +/- 12) with isolated AS and 51 age- and gender-matched healthy controls comprised the study group. Left ventricular mass index (LVMI) was calculated by the Devereux formula, and we used continuous-wave Doppler (n = 15) and cardiac catheterization (n = 36) for the determination of the maximum aortic valve pressure gradient (PG). RESULTS: Corrected QTd (QTcd) (89 +/- 39 vs. 49 +/- 15 ms, p < 0.001) and LVMI (176 +/- 69 g/m2 vs. 101 +/- 28 g/m2, p < 0.001) in patients with AS were significantly different from those in the control group. The group of 21 patients had a significantly greater number of 24-h mean ventricular premature beats (VPB) and mean number of couplet VT episodes than did the control group (p < 0.05). QTcd also correlated significantly well with LVMI (r = 0.58, p < 0.001), PG (r = 0.41, p = 0.003), and number of 24-h VPB (r = 0.56, p = 0.008). With respect to symptoms (e.g., angina, syncope, and dyspnea) patients without symptoms (n = 19) displayed less QTcd (71 +/- 31 vs. 100 +/- 39 ms, p = 0.007) and less LVMI (144 +/- 80 g/m2 vs. 195 +/- 57 g/m2, p = 0.01) than patients with symptoms. Statistical analysis was similar for all variables with uncorrected QTd values. CONCLUSION: We found that ventricular repolarization heterogeneity was greater in patients with AS than in controls. Our findings also showed that QTd in the patient group correlates well with LVMI, severity of AS, and PG. The present results suggest that serious ventricular arrhythmias in patients with AS may be due to spatial ventricular repolarization abnormality.

Aged↗
PubMed2000

QT dispersion as a predictor of arrhythmic events in patients with ankylosing spondylitis.

OBJECTIVE: The aim of the study was to evaluate QT dispersion (QTd), an indicator of repolarization heterogeneity, and its relation to ventricular arrhythmias in patients with ankylosing spondylitis (AS). METHODS: A full history, clinical examination, electrocardiograms and 24-h Holter monitoring were performed in 88 AS patients and 31 volunteers of similar age and sex. Groups were compared based on electrocardiographic abnormality, QTd, arrhythmias and heart blocks. RESULTS: QTd and corrected QTd (QTcd) were significantly greater in AS patients than controls (QTd, 52.8 +/- 15.1 vs 35.5 +/- 8.9 ms, P: < 0.0001; QTcd, 60.3 +/- 16.1 vs 39.4 +/- 10.7 ms, P: < 0.0001). The magnitudes of these parameters were associated with the duration of the disease (QTd, r = 0.56, P: < 0.01; QTcd, r = 0.60, P: < 0.001). The frequency of ventricular extrasystoles was found to be correlated with QTd (r = 0.35, P: < 0.01) and QTcd (r = 0.33, P: < 0. 01). CONCLUSION: Involvement of the heart may be seen in AS during the early clinical course of the disease. QTd may give clues about the presence of arrhythmias and can be used as a new technique for the evaluation of asymptomatic patients. Earlier detection of cardiac involvement could alter the prognosis of the patients.

Adult↗
PubMed2000

Ruptured aneurysm of the sinus of Valsalva in association with persistent left superior vena cava--a case report.

A 58-year-old man presenting with chest pain and dyspnea was diagnosed by transesophageal echocardiography and cardiac catheterization to have the rare combination of ruptured aneurysm of noncoronary sinus of Valsalva into the right ventricle in association with persistent left superior vena cava. These defects were confirmed at cardiac surgery. This case shows the importance of complementary use of invasive and noninvasive methods together in the diagnosis of rare combinations of lesions.

Aortic Rupture↗
PubMed2000

Inappropriate shocks diagnosed by stored electrograms of implantable cardioverter defibrillators--two case reports.

An implantable cardioverter defibrillator is an important therapeutic option for patients with high risk of life-threatening ventricular arrhythmias. However, their use is also associated with several complications including inappropriate shock. Although the most frequent cause of inappropriate shock is supraventricular tachyarrhythmias, lead fracture can also be associated with inappropriate shock. Diagnosis of lead fracture can be made by chest x-ray radiography, fluoroscopic examination, interrogation of the device, and intracardiac electrograms. In this report, the authors present two cases of inappropriate shock due to lead fractures in the costoclavicular region that could only be diagnosed by the help of stored intracardiac electrograms. Methods for diagnosis of lead fractures and modalities to avoid recurrences are also discussed.

Artifacts↗
PubMed2000

T wave alternans can decrease after coronary revascularization.

Clinical observations and animal experiments indicate that T wave alternans (TWA) is associated with an increased propensity for ventricular fibrillation, and thus it may be considered as a noninvasive marker of life-threatening ventricular arrhythmias. There is substantial evidence indicating that TWA is an intrinsic property of ischemic myocardium. This study was performed to determine the role of percutaneous transluminal coronary angioplasty (PTCA)-induced myocardial ischemia in the development of TWA and the effects of revascularization. The authors recorded bipolar X, Y, and Z leads of 111 consecutive patients (mean age: 56 years) undergoing PTCA before, during, and 24 hours after the procedure. T wave alternans signal was calculated in 97 patients (43 left anterior descending, 26 right coronary artery, and 28 circumflex or major obtuse margin branch) by fast Fourier transformation technique after signal processing. Twenty-four hours after the procedure, the mean and peak X, Y, and Z values for TWA had all been significantly reduced from baseline and during balloon inflation (p<0.01). The findings point out that induced ischemia could be a trigger for T wave alternans, and successful revascularization can reduce alternans.

Angioplasty, Balloon, Coronary↗
PubMed1999

Circadian variations of QTc dispersion: is it a clue to morning increase of sudden cardiac death?

BACKGROUND: Several studies related to cardiac events including sudden death have shown a peak incidence in the early morning hours. It has also been known that acute ischemia is a potent stimulus to increased dispersion of repolarization and development of malignant arrhythmias. HYPOTHESIS: The purpose of the present study was to investigate diurnal variations of corrected QT dispersion (QTcD) in patients with coronary artery disease (CAD) (Group 1) compared with controls with normal coronary angiograms (Group 2). METHODS: We investigated a total of 110 patients who had been referred for coronary angiography, of whom 62 (42 men, 20 women; age 55 +/- 7 years) had double- or triple-vessel disease, and of whom 48 (31 men, 17 women; age 54 +/- 9 years) had normal coronary angiograms. QTcD measurements were calculated from a 12-lead resting electrocardiogram (ECG) during sinus rhythm. These ECGs were obtained for each patient in the morning, at noon, in the evening, and at night on the day after performance of coronary angiography. QTcD was significantly greater in patients with abnormal coronary angiograms (Group 1) than in patients with angiographically documented normal coronary arteries (Group 2). This difference appeared to be more prominent in the morning hours (p < 0.001) than at other times. QTcD in the evening and night hours was not statistically different (p > 0.05) between both groups. We also compared intragroup QTcD values: QTcD values were significantly increased in the morning hours and were more prominent in Group 1 than in Group 2. CONCLUSIONS: Our data suggest that QTcD has a circadian variation with an increase in the morning hours, especially in patients with coronary artery disease. This finding was thought to be an explanation for the role played by sympathetic nervous system in the occurrence of acute cardiac events and sudden death during these hours.

Acute Disease↗
PubMed1999

Relationship between endogenous sex hormone levels, lipoproteins and coronary atherosclerosis in men undergoing coronary angiography.

This study was carried out in order to investigate the relationship between endogenous sex steroid hormones and coronary artery disease (CAD). Three hundred and thirty-seven men undergoing coronary angiography were enrolled in the study. Total testosterone, estradiol, free testosterone levels in men with CAD (n = 213) were compared to those of men without CAD (n = 124). No significant differences were found in the serum concentrations of estradiol, total and free testosterone and serum lipid profile between the two groups. Total and free testosterone were negatively (p < 0.05 to p < 0.001) and estradiol was positively (p < 0.05) correlated with age in both groups. Total cholesterol and low-density-lipoprotein levels were positively correlated with the level of free testosterone (r = 0.221, p < 0.01; r = 0.173, p < 0.05, respectively), and high-density-lipoprotein levels were negatively correlated with total testosterone in patients with CAD (r = -0.166, p < 0.05). The results of this study do not support the role of sex steroid hormones in CAD. However, the relationship between sex steroids and serum lipids needs further clarification.

Adult↗