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Biomedical subjects

A Oto

Publications and source records attributed to A Oto.

At least 19 recordsLinked to original sources

Effects of stent coating on platelets and endothelial cells after intracoronary stent implantation.

BACKGROUND: Adhesion molecules are known to be important in the regulation of endothelial cell and platelet functions. Increased platelets P-selectin expression is a marker of stent thrombosis after uncoated stent placement. HYPOTHESIS: The aim of this study was to compare the effects of intracoronary placement of phosphorylcholine (PC)-coated, versus heparin-coated, versus uncoated stents on platelets and endothelial activity. METHODS: Thirty patients (age 55 +/- 10, 27 men) with significant proximal left anterior descending coronary artery stenoses were randomized to elective implantation of PC-coated, versus heparin-coated, versus uncoated stents. Following stent placement, intravenous heparin and aspirin plus ticlopidine were administered. Venous plasma soluble E-selectin, sP-selectin, and intercellular adhesion molecule-l levels were measured before the procedure and 24 and 48 h thereafter as markers of platelet and endothelial cell activation. Patients were excluded if they had a disease known to influence platelet and endothelial cell function. RESULTS: Plasma sP-selectin levels decreased significantly after implantation of PC- and heparin-coated stents (p = 0.04), but remained unchanged in patients randomized to uncoated stents. Plasma sE-selectin levels increased significantly after uncoated stent placement (p = 0.04) and remained unchanged after coated stent implantation. CONCLUSION: In patients treated with combined antiplatelet therapy, implantation of PC- and heparin-coated stents decreased platelet activity without activating endothelial cells, whereas placement of uncoated stents led to endothelial activation without changing platelet activity. These results suggest that PC-coated and heparin-coated stents may be advantageous in limiting thrombotic complications.

Angioplasty, Balloon, Coronary↗

Soy protein diet significantly improves endothelial function and lipid parameters.

BACKGROUND: Replacement of animal protein with soy protein in the diet is associated with decreased cholesterol levels. However, the effects of soy protein diet on endothelial function are not well known. HYPOTHESIS: The aim of the study was to investigate the effects of soy protein diet on plasma lipids and endothelial function parameters assessed by two different methods. METHODS: Twenty hypercholesterolemic, nonsmoker male patients (age 50.1+/-11.8 years), with a normal body mass index, were included. After calculating their daily requirements, a diet with 25-30% of energy from fats. 10-12% from proteins, and the rest from carbohydrates was instituted. Sixty percent of the animal source proteins of the diet were substituted by soy. The anthropometric measures, lipid parameters, and endothelial functions of the subjects were assessed at baseline and 6 weeks after soy protein diet. Flow-mediated endothelium-dependent dilatation (EDD) and plasma thrombomodulin (TM) levels were evaluated as endothelial function parameters. RESULTS: After diet, plasma total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, and triglyceride levels decreased significantly (p <0.001, p < 0.001, p = 0.039, and p = 0.001, respectively). The mean plasma TM levels were also significantly reduced with diet (p = 0.004). Studies of the brachial artery indicated a borderline dilatation in baseline brachial artery diameter (p = 0.05), however the diameter at reactive hyperemia was significantly larger after diet (p<0.001), resulting in a significant improvement of EDD (p = 0.002). CONCLUSION: Soy protein diet significantly improves plasma lipid profile in patients with hypercholesterolemia. Furthermore, the endothelial function, as judged by two different methods (EDD and plasma TM levels), also improves with soy protein diet.

Adult↗

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↗

Diastolic dysfunction and increased serum homocysteine concentrations may contribute to increased cardiovascular risk in patients with polycystic ovary syndrome.

OBJECTIVE: To assess cardiac flow parameters in patients with polycystic ovary syndrome (PCOS). DESIGN: A prospective case-control study. SETTING: University-based hospital. PATIENT(S): Thirty consecutive patients with PCOS were enrolled. Thirty women with regular menstrual cycles served as the controls. INTERVENTION(S): Systolic and diastolic function parameters were assessed by standard two-dimensional and M-mode echocardiography. Insulin sensitivity was evaluated by a standard 75-g oral glucose tolerance test and area-under-curve insulin analysis. Serum hormones, lipid profile, homocysteine, vitamin B(12), folate, fibrinogen, uric acid, and plasminogen activator inhibitor-I concentrations were measured. MAIN OUTCOME MEASURE(S): Systolic and diastolic function parameters, insulin sensitivity and serum homocysteine levels. RESULT(S): The mean serum homocysteine and uric acid concentrations were significantly higher in the PCOS group. Patients with PCOS had significant hyperinsulinemia. All systolic function parameters were comparable between the two groups. However, patients with PCOS had significantly lower peak mitral flow velocity in early diastole and significantly lower ratio between the early and late peak mitral flow velocities and also had significantly longer isovolumic relaxation time, reflecting a trend for nonrestrictive-type diastolic dysfunction. The area-under-curve insulin correlated positively with peak mitral flow velocity in late diastole (r = 0.375). The mean cholesterol/high-density lipoprotein ratio correlated negatively with mean mitral flow velocity in early diastole (E) peak (r = -0.474). The mean fasting insulin level correlated negatively with mean E/A ratio (r = -0.387). CONCLUSION(S): Diastolic dysfunction and increased serum homocysteine concentrations may contribute to increased cardiovascular disease risk in patients with PCOS.

Adult↗

A retrospective review of 228 episodes of infective endocarditis where rheumatic valvular disease is still common.

Two hundred and twenty-eight episodes of infective endocarditis in adult patients (mean age 36 years) were reviewed retrospectively. There were 183 episodes (80%) of native valve, 15 (7%) early prosthetic valve and 30 (13%) late prosthetic valve endocarditis. The most common predisposing factor was rheumatic valvular disease (65%). None of the patients were intravenous drug users. According to the Duke criteria, the number of definite, probable and rejected episodes were 121 (53%), 94 (41%) and 13 (6%), respectively. Additional minor criteria increased the number of definite endocarditis to 82%. The Duke criteria are not primarily intended to influence treatment decisions but are helpful in standardising research activities. The choice of the level of sensitivity or specificity of the criteria may be adjusted according to the aim of the study and prevalence of disease in a particular area. More sensitive criteria may be valuable in those countries where the prevalence of rheumatic valvular disease is still high.

Adolescent↗

The effects of chronic carvedilol therapy on QT dispersion in patients with congestive heart failure.

BACKGROUND: Carvedilol therapy reduces mortality from sudden cardiac death and progressive pump failure in congestive heart failure (CHF). However, the effect(s) of carvedilol on ventricular repolarization characteristics is unclear. AIM: The aim of the study was to investigate the effects of chronic carvedilol therapy on ventricular repolarization characteristics as assessed by QT dispersion (QTd) in patients with CHF. METHOD: Nineteen patients (age 53+/-12 years; 16 male, three female) with CHF (eight ischemic, 11 non-ischemic dilated cardiomyopathy) were prospectively included in the study. Carvedilol was administered in addition to standard therapy for CHF at a dose of 3.125 mg bid and uptitrated biweekly to the maximum tolerated dose. From standard 12-lead electrocardiograms the maximum and minimum QT intervals (QTmax, QTmin), QTd, corrected QT intervals (QTcmax, QTcmin) and corrected QTd (QTcd) values were calculated at baseline, after the 2nd and the 16th month of carvedilol therapy. RESULTS: A significant reduction was noted in the QTd and QTcd values with carvedilol therapy after the 16th month (QTd: 81+/-22 ms vs. 40+/-4.3 ms P<0.001; QTcd: 91+/-25 ms vs. 51+/-7 ms P<0.001), but not after the 2nd month (P>0.05). The resting heart rate was also significantly reduced after a 16-month course of carvedilol therapy (78+/-13 bpm vs. 66+/-15 bpm, P<0.05). Carvedilol therapy did not alter QTmax and QTcmax intervals (P>0.05), however, QT min and QTcmin significantly increased with carvedilol at the 16th month (P<0.001 and P<0.01, respectively). CONCLUSION: Long-term carvedilol therapy was associated with a reduction in QTd, an effect that might contribute to the favorable effects of carvedilol in reducing sudden cardiac death in CHF.

Adrenergic beta-Antagonists↗

The World Survey of Cardiac Pacing and Implantable Cardioverter Defibrillators: calendar year 1997--Europe.

The registry of the European Working Group on Cardiac Pacing (EWGCP) is based on the European Pacemaker Identification Card originally designed in July 1978. National registration centers collect the local data and send aggregated annual data to the EWGCP. For 1997, data were obtained from 2,887 hospitals in 20 European countries representing a population of 568 million. Across all participating countries, the median value for all implanted pacemakers was 378 per million population. For initial pacemaker implants, the median value was 290 per million population. Single chamber atrial pacing was important in Denmark, the Netherlands, Poland, Slovak Republic, Spain, and Sweden for the treatment of sick sinus syndrome. Dual chamber pacing accounted for < 50% of initial implants in only 5 of 14 countries for atrioventricular block, and in only 3 of 15 countries for sick sinus syndrome. In 7 of 15 countries, unipolar ventricular leads were used in > or = 50% of cases. In 6 of 14 countries, there was > 15% use of unipolar atrial leads. Nine of 13 countries frequently used atrial active-fixation leads. For the 1997 survey, ICD data were obtained from 16 countries. The total number of ICDs per million population was a median value of 14. Initial ICD implants per million population was 11. Only 3 of 16 countries implanted a total of 30 or more ICDs per million population. Pacing and ICD practices were dependent on the availability of medical and technical resources and influenced by economic constraints inherent in health care administration and insurance coverage patterns.

Aged↗

Hormone replacement therapy shortens QT dispersion in healthy postmenopausal women.

BACKGROUND: The aim of the study was to investigate the effects of hormone replacement therapy (HRT) on myocardial repolarization characteristics in postmenopausal women without coronary artery disease. METHODS: Fifty-one consecutive healthy postmenopausal women (age 48 +/- 5) with negative exercise stress testing were prospectively enrolled into the study. Standard 12-lead electrocardiograms were obtained to evaluate the effects of 6 months of HRT on QT intervals, corrected QT intervals (QTcmax and QTcmin), QT dispersion (QTd), and corrected QTd (QTcd). Hormone regimens were continuous 0.625 mg/day conjugated equine estrogen (CEE) plus 2.5 mg/day medroxyprogesterone acetate (MPA) or 0.625 mg/day CEE alone depending on the hysterectomy status. RESULTS: Although not statistically significant, CEE alone or in combination with MPA increased QTmax and QTmin values. However, the increase in QTmin was greater than the increase in QTmax, which resulted in statistically significant shortening of QTd (P = 0.007 in CEE and P < 0.001 in CEE + MPA groups). There was a significant prolongation of QTcmin values after 6 months in patients assigned to the CEE group (P = 0.001). The QTcd values were significantly shortened by HRT with both regimens (for CEE group 49 +/- 13 ms vs 38 +/- 13 ms, P = 0.01; for CEE + MPA group 49 +/- 14 ms vs 36 +/- 13, P < 0.001). CONCLUSION: HRT significantly decreased the QTd and QTcd in postmenopausal women without coronary artery disease, independent of the addition of MPA to the regimen. This improvement in myocardial repolarization may be one of the mechanisms of the favorable effects of HRT on cardiovascular system. However, the clinical implications of the shortening of QTd in postmenopausal women with HRT must be clarified.

Adult↗

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↗

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↗

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↗

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↗

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↗