Objective: Microvolt T-wave Alternans (TWA) is associated with abnormal repolarization and predicts arrhythmic mortality in patients with previous myocardial infarction (MI). Infarct tissue size and heterogeneity characterized by cardiac magnetic resonance (CMR) has been shown to be associated with arrhythmogenic substrates and sudden cardiac death. Although both delayed enhancement-CMR (de-CMR) and TWA are useful in risk stratification of post-MI patients with preserved left ventricular function, the relationship between scar size and TWA has not studied yet. In this study, we aimed to study the relation between TWA and scar size and characteristics assessed with CMR in post-MI patients (pts) with relatively preserved systolic function presented with nonsustained VT. Methods: This observational cross-sectional study was enrolled 36 post-MI patients with mild-systolic dysfunction and non-sustained ventricular tachycardia. Eight pts were excluded. Both TWA and contrast enhanced CMR were performed. Left ventricular ejection fraction (LVEF), dense scar, peri-infarct zone and total scar masses were assessed and these values to left ventricular (LV) mass ratios were calculated. Infarct ratios and characteristics were determined and compared among patients with negative TWA and those with positive TWA. Results: For the positive (n=12) vs. negative (n=16) TWA patients there were no significant difference between LVEF (44.9±5.4% vs. 44.0±3.2%, p=NS) and LV masses (121.89±26.56 g vs. 106.14±21.16 g, p=NS). The ratio of scar core to LV mass (3.37±0.68% vs. 3.31±1.01%, p=NS), peri-infarct zone to LV mass (23.61±7.93% vs. 21.64±9.08%, p=NS), total scar to LV mass (26.98±7.86% vs. 24.96±9.62%, p=NS) were all similar. Conclusion: There were no association between scar size and infarct heterogeneity and prevelance of TWA in post-MI patients with relatively preserved LVEF with non-sustained VT. Our data suggest that these two modalities may reflect different arrhythmogenic mechanisms in this cohort. (Anadolu Kardiyol Derg 2014; 14: 442-7)
Objective:Viscum album L. has favorable cardiovascular effects including antihypertensive and vasorelaxant activity, and the nitric oxide (NO) pathway upregulation has been proposed to be the underlying mechanism. NO also plays an important role in the pathophysiology of heart failure. However, its effects on cardiac systolic function are unclear.Methods:A total of 30 male Wistar albino rats at 12 weeks of age were randomly divided into three groups: control, isoproterenol-induced heart failure group (ISO), and isoproterenol-induced heart failure + V. album treatment group (VA) groups (n=10 in each group). V. album was orally given at a dose of 250 mg/kg/day by gavage. Parameters of heart failure were compared among the groups. Tamhane’s T2 test, paired sample t-test, and Bonferroni methods were used for statistical analysis.Results:V. album resulted in an improvement in all parameters of heart failure including left ventricular diameters (6.34±0.23 mm, 6.98±0.35 mm, and 6.71±0.10 mm for left ventricular end-diastolic diameter in control, ISO, and VA groups, respectively, p<0.05), ejection fraction (73.3±3.1%, 56.7±2.6%, and 65.2±1.5% for control, ISO, and VA groups, respectively, p<0.05), serum NT-proBNP levels, and histopathological changes. V. album treatment resulted in a statistically significant attenuation of increased levels of NO and iNOS (p<0.0001). The levels of hs-CRP were also found to be lower in the VA group compared with the controls and ISO groups (p<0.01).Conclusion:V. album exerted favorable effects on left ventricular function in isoproterenol-induced heart failure rats. Upregulation of the NO pathway seems to be the possible pathophysiological mechanism. Favorable vascular outcomes can also be speculated considering the reduction in serum hs-CRP levels.
Interferon gamma (IFN-γ) is a multifunctional cytokine that plays an important role in modulating almost all phases of the immune response and may be responsible for the increased valvular fibrosis and calcification in the pathogenesis of rheumatic heart disease (RHD). The aim of this study was to investigate the possible relationship between the IFN-γ +874 T/A polymorphism and the severity of valvular damage in the Turkish population. The IFN-γ genotypes were determined in 152 RHD patients and 151 healthy controls by ARMS-PCR. Differences in genotype distribution between patients with RHD and control were evaluated by the χ test. All statistical analyses were performed with SPSS 15.0 Software program. Frequency of the AA genotype was found to be significantly lower and the TT genotype significantly higher in the RHD group compared to controls (p = 0.002 and p = 0.018, respectively). The TT genotype was found to be significantly higher (26.8% vs. 9.1%, p = 0.009) and the AA genotype significantly lower (29.1% vs. 8.2%, p = 0.001) in the severe valvular disease (SVD) group compared to mild valvular disease group. In the SVD group, 79 patients had mitral balloon valvotomy and/or mitral valve replacement and had significantly higher TT genotype compared to patients with medical follow-up (30.4% vs. 19%, p = 0.001). The data demonstrated that TT genotype is associated with both RHD and the severity of RHD.
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