Objective: The purpose of this study was to investigate the effects of hyperglycemia on atrial interstitial fibrosis, ionic remodeling and vulnerability to atrial fibrillation (AF) in alloxan-induced diabetic rabbits. Methods: Sixty Japanese rabbits were randomly assigned to alloxan-induced diabetic group (n=30) and control group (n=30). Ten rabbits in each group were respectively used to electrophysiological and histological study, patch-clamp study and Western blotting analysis. Langendorff perfusion was used to record inter-atrial conduction time (IACT), atrial effective refractory period (AERP) and dispersion (AERPD) and vulnerability to AF. Histological study was measured by Sirius-red stain. Patch-clamp technique was used to measure action potential duration (APD) and atrial ionic currents (INa and ICaL). Western blotting was applied to assess atrial protein expression of transforming growth factor beta 1 (TGFβ1). Results: Compared with control group, electrophysiological studies showed IACT was prolonged (37.91±6.81 vs. 27.43±1.63ms, p<0.01), AERPD was increased (30.37±8.33 vs. 14.70±5.16ms, p<0.01) in diabetic group. Inducibility of AF in diabetic group was significantly higher than in controls (8/10 vs. 1/10 of animals, p<0.01). Collagen volume fraction was increased (6.20±0.64% vs. 2.15±0.21%, p<0.01) in diabetic group. Patch-clamp studies demonstrated APD90 and APD50 were prolonged in diabetic rabbits (p<0.05 vs. control). The densities of INa were reduced and the densities of ICaL were increased (p<0.01 vs. control). Protein expression of TGFβ1 was increased in diabetic group (p<0.001 vs. control). Conclusion: Our study suggests that hyperglycemia contributes to atrial interstitial fibrosis, ionic remodeling and vulnerability to AF in diabetic rabbits, resulting in atrial structural remodeling and electrical remodeling for the development and perpetuation of AF.

Objective: Flow-mediated dilation (FMD) is used to evaluate endothelial functions. Computer-assisted analysis utilizing edge detection permits continuous measurements along the vessel wall. We have developed a new fully automated software program to allow accurate and reproducible measurement. Methods: FMD has been measured and analyzed in 18 coronary artery disease (CAD) patients and 17 controls both by manually and by the software developed (computer supported) methods. The agreement between methods was assessed by Bland-Altman analysis. Results: The mean age, body mass index and cardiovascular risk factors were higher in CAD group. Automated FMD% measurement for the control subjects was 18.3±8.5 and 6.8±6.5 for the CAD group (p=0.0001). The intraobserver and interobserver correlation for automated measurement was high (r=0.974, r=0.981, r=0.937, r=0.918, respectively). Manual FMD% at 60th second was correlated with automated FMD % (r=0.471, p=0.004). Conclusions: The new fully automated software© can be used to precise measurement of FMD with low intra- and interobserver variability than manual assessment.

Objective: In this prospective study, we aimed to investigate acute effect of nasal continuous positive airway pressure (CPAP) therapy on the endothelial function of patients with obstructive sleep apnea syndrome (OSA) by using brachial artery flow mediated dilatation (FMD) method. Methods: Newly diagnosed thirty OSA patients with ages between 29 and 72 years were included in this study. FMD and high sensitivity C-reactive protein (hsCRP) values of patients obtained before and after CPAP dose titration test were compared with paired samples t test or Wilcoxon signed ranks test. Results: With CPAP therapy apnea hypopnea indices were reduced (60.6±24.9/h vs. 9.6±7.9/h; p<0.001) and oxygen desaturation indices recovered (50±27/h vs. 6±7/h; p<0.001). Heart rates of patients decreased after CPAP therapy (80±10/min vs. 73±8/min; p=0.003). FMD values significantly increased after CPAP (8.55±5.82 percent vs. 12.08±7.17 percent; p=0.003). HsCRP values after CPAP were not different from baseline values Conclusion: Acute improvement of the endothelial function with one night CPAP therapy suggests endothelial dysfunction in OSA patients to be result of acute pathophysiologic factors. In intermediate and severe OSA patients, CPAP therapy may be considered in acute treatment of diseases associated with endothelial dysfunction.

Objective: Endothelial dysfunction is considered the first stage in the development of atherosclerosis and assessed by flow-mediated dilatation (FMD) and aortic flow velocity propagation (AVP). Ankle-brachial index (ABI) is used to assess peripheral arterial disease and is associated with FMD but the relationship between ABI and AVP is unknown. In this study, we aimed to search the association between AVP, and ABI in patients with newly diagnosed hypertension. Methods: Sixty-eight patients with newly diagnosed hypertension and 34 healthy subjects were enrolled in the cross-sectional observational study. The maximum ankle arterial pres-sures were divided by the maximum of the brachial arterial pressures to calculate the ABI. AVP was calculated from dividing the distance between points corresponding to the begin-ning and end of the propagation slope, to the duration between corresponding time points proximally descending aorta. Statistical analysis was performed using Student t-test, Chi-square test, Pearson correlation and linear regression analyses. Results: Age and gender of both groups were similar. Compared to control group E decelera-tion time of early diastolic flow velocity (184.0±32.2 vs. 217.1±38.6, p<0.001), isovolumic relaxation time (95.5±19.4 vs. 105.7±18.1, p<0.001) and body mass index (25.6±5.1 vs. 27.5±3.8, p=0.044) values were significantly higher, while ABI (1.08±0.07 vs. 1.14±0.07, p=0.001) and AVP (54.97±9.3 vs. 69.17±10.8 cm/sec, p=0.001) values were significantly lower in hypertensive patients. There was a significant correlation between AVP and ABI (r=0.279, p=0.005). Both ABI and AVP were independent predictors of hypertension (OR - 0.353, 95%CI 0.151-0.826, p=0.02 and OR - 0.133, 95%CI 0.0502-0.35, p=0.001, respectively). Conclusion: Our data indicate that in patients with isolated hypertension AVP and ABI decrease. We also conclude that AVP is directly associated with ABI.

Objective: Fragmented QRS complexes (fQRS) are defined as various RSR′ patterns in 2 contiguous leads corresponding to a major coronary artery territory. Although the reason of association between fQRS and cardiac events was documented as cardiac fibrosis, the predictive role of fQRS was not studied for postoperative atrial fibrillation (POAF) which is a frequent and serious complication in patients undergoing isolated coronary artery bypass graft (CABG) surgery. Therefore, this issue was investigated in the present study. Methods: The current study has a prospective observational design. Two hundred and seventy two eligible patients who underwent isolated CABG surgery were enrolled consecutively. The patients were divided in two groups with post-op atrial fibrillation (AF) and non-AF. The occurrence of new-onset AF following CABG and the relationship with fQRS were searched. The logistic regression analysis was used to determine independent predictors for POAF. The sensitivity and specificity of study variables in predicting POAF were calculated using a receiver-operating characteristic curve (ROC). Results: POAF occurred in 62 of 272 patients (22.8%). Patients with POAF were generally older (p<0.001) and female (p=0.006), with preexisting hypertension (p=0.008), lower hemoglobin levels (p=0.011), chronic obstructive lung disease (p=0.003), prolonged QRS time (p=0.004), and higher EUROSCORE (p<0.001) compared to non-AF patients. Patients with POAF had lower left ventricular ejection fraction (p<0.001) and high fQRS rate (p<0.001), but similar left atrial size (LA, p=NS). Interestingly, LA size was significantly enlarged in patients with fQRS (3.8±0.6 vs. 4.1±0.5 cm, p=0.002). In addition, the patients with POAF had prolonged stay in the cardiac surgery intensive-care unit (p<0.001) and extended in-hospital care (p=0.001). New-onset POAF was significantly related to the presence and number of fQRS. In the logistic regression analysis, only age (OR: 1.044, 95% CI: 1.008-1.082, p=0.016), female gender (OR: 2.347, 95% CI: 1.079-5.106, p=0.031), the presence and number of fQRS (OR: 6.020, 95% CI: 3.152-11.5 and OR: 1.522, 95% CI: 1.282-1.807, both of, p<0.001) were independent predictors of POAF. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and the diagnostic accuracy (DA) of presence of fQRS on pre-op electrocardiogram to predict POAF were 66%, 76%, 45%, 88% and 74%, respectively. The area under ROC was found as 0.733 (p<0.001, 95% CI: 0.657-0.810). Conclusion: In our study, we found that new-onset POAF was independently related to the presence and number of fQRS in patients undergoing CABG surgery. In addition, fQRS on pre-op surface ECG had high predictive values for new-onset POAF.

Objective: The aim of this prospective study was to evaluate the diagnostic value of heart-type fatty acid binding protein (H-FABP) determined by qualitative immunoassay method for the detection of minor myocardial damage (MMD) in patients with non-ST elevation acute coronary syndrome (NSTE-ACS). Methods: The study consisted of 62 patients with NSTE-ACS. Cardiac troponin I (cTnI) and creatine kinase MB isoenzyme (CK-MB) values were measured at arrival. Myoglobin and H-FABP were obtained if cTnI level was found to be elevated. A control group included 20 subjects with normal cTnI and CK-MB values. H-FABP was determined by a rapid qualitative immunochromatographic test. Patients were classified as MMD-ACS group if they had abnormal cTnI and normal CK-MB (n=24) and as NSTEMI-ACS group if they had elevated both cTnI and CK-MB (n=38). The diagnostic accuracy of H-FABP for minor myocardial damage was determined using ROC analysis. Results: The sensitivity of the H-FABP was significantly higher for NSTEMI-ACS than for MMD-ACS (44.7% vs 0%, p<0.001) and its specificity was 95% for both groups. The diagnostic efficacy rates for myoglobin and H-FABP were 75% and 43% for MMD-ACS, 74% and 62% for NSTEMI-ACS. Positive predictive value for H-FABP and myoglobin were found to be 0% and 80.8% in MMD-ACS, 94% and 87% in NSTEMI-ACS and negative predictive value was 44% and 69.5% in MMD-ACS, 47.5% and 59% in NSTEMI-ACS, respectively. AUC for myoglobin was significantly greater than that for H-FABP in MMD-ACS group (0.754 vs 0.525, p=0.027). The sensitivity of the H-FABP was significantly higher in patients with >3-fold increase in cTnI than those with <3-fold increase in cTnI (46.8% vs. 6.7%, p< 0.001). A positive correlation was found between the magnitude of cTnI rise and H-FABP results (r=0.45, p<0.001). Conclusions: H-FABP determined by the rapid qualitative immunochromatographic test has almost similar diagnostic value to that of myoglobin for identifying NSTEMI-ACS, however, does not seem to represent diagnostic potential for the detection of MMD.

Objective: The aim of this study is to investigate the relationship between serum thyroid hormone levels that are within the normal range and the presence and severity of coronary artery disease (CAD) in patients referred for coronary angiography. Methods: In this observational study, we enrolled 119 consecutive patients (77 men, mean age 60.7±13.8 years) who underwent coronary angiography. Blood samples were tested for thyroid stimulating hormone (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) concentrations. Additionally, risk factors, clinical characteristics and angiographic results were obtained. The patients were separated into two groups according to the Gensini score as those with mild or severe atherosclerosis. Statistical analysis was performed using the Chi-square, Mann-Whitney U, correlation and logistic regression tests, and ROC analysis. Results: FT3 levels were significantly lower in subjects with CAD (4.0±0.7 vs. 4.6±0.6 pmol/L; p<0.001). Moreover, lower FT3 levels were found in patients with severe atherosclerosis (3.9±0.7 vs. 4.5±0.6 pmol/L; p<0.001). Logistic regression analysis demonstrated that the lower FT3 levels were associated with the presence (OR =0.266, 95% CI: 0.097-0.731, p=0.01) and severity (OR=0.238, 95% CI: 0.083-0.685, p=0.008) of CAD. In the ROC analysis, a level of FT3 ≤4.2 pmol/L was found to predict the presence of CAD with 69% sensitivity and 71% specificity (AUC: 0.744, 95% CI: 0.653-0.834, p<0.001); and the severity of CAD with 75% sensitivity and 67% specificity (AUC: 0.733, 95% CI: 0.642-0.824, p<0.001). Conclusions: FT3 levels within the normal range were inversely correlated with the presence and severity of CAD. Moreover, lower FT3 concentrations were correlated with the Gensini score and independently predicted the presence and severity of CAD. Thus, the FT3 levels may be used as the indicator of increased risk for CAD.