1. Association Between Atrial Fibrillation And Chronic Helicobacter Pylori Infection Or C-reactive Protein 2. Low-Dosage Epinephrine Effects On The Cardiac Repolarization In Chinese Normal Young Subjects And Patients With Syncope

Objective To investigate the relationship between atrial fibrillation (AF)and chronic Helicobacter pylori infection (HP) or C-reactive protein(CRP).Methods 66 atrial fibrillation patients as the experimental group and 67paroxysmal supraventricular tachycardia (PSVT) patients as the controlgroup were included in this study. Serum concentrations of the IgGantibodies of HP (HP-IgG) of the two groups were determined by theenzyme linked immunosorbent assay (ELISA) HP-IgG kit.Concentrations of CRP were measured with rate nephelometry. The HPIgG and CRP concentrations were compared between the experimentalgroup and the control one, and the associations were analyzed betweenHP infection and AF or other factors which may impact HP-IgG.Results No difference was shown in the positive rate (43.9% Vs 50.7%; P=0.432) and logarithm value (1.38±0.52Vs1.50±0.44; P=0.210) ofHP-IgG between AF group and the control one. All the 95% confidenceinterval of odds ratios for association between HP infection and AF orother factors contained 1.0, which means there is no significantassociation between them. The CRP concentration of AF group wassignificantly higher than that of the control one (median1.17 Vs 0.65 mg/d, P=0.029). But There was no significant difference in CRPconcentrations between the paroxysmal and chronic atrial fibrillation group(1.08mg/dl vs1.38mg/dl, P=0.217).Conclusions CRP in AF group was higher than that in the control one,which indicates that AF is related to some inflammation. We found norelationship between HP infection and AF. Objective To investigate low-dosage epinephrine effects on cardiacrepolarization in Chinese normal young subjects (20-30 years old) andpatients with syncope. And to assess the false positive rate of QT changein healthy subjects with long-QT syndrome diagnostic criteria currentlyrecommended of epinephrine stess test for future settlement of the criteriafor the test in Chinese people.Methods 50 healthy subjects as the normal group and 24 patients withsyncope without structural diseases as the syncope group were evaluatedduring an epinephrine stress test that involved a 25-minute infusionprotocol (0.025 to 0.15μg/kg/minute). 12-lead electrocardiogram (ECG),heart rate (HR) and blood pressure (BP) were recorded on resting time, atthe conclusion of each dose of epinephrine and 10 minutes after infusionwas stopped. Repolarization parameters (QT interval, rate adjusted QTinterval—QT_C interval, T-and U-wave amplitude) of the ECGs weremeasured. Positive rates of the paradoxical QT response were assessedwith criteria recommended abroad.Results Female normal group (female group) possessed longer baselineQT_C (422.5±19.2Vs411.0±21.3ms, P=0.049) and lower T-wave amplitude(0.58±0.21mv Vs 0.84±0.21mv, P＜0.001) than male one. During infusionnormal subjects exhibited shortening of QT intervals, lengthening of QT_Cintervals, various changes in T-wave morphology and notable U waves. The longest absolute QT, QT_C and greatest QT_C increase of female groupwere longer than those of male one (P=0.043, 0.000 and 0.040,respectively). No difference was shown in the greatest△QT, T-wavemorphology category between the two groups. The longest△QT duringinfusion of≤0.1μg·kg^-1·min^<sub>-1-dosed epinephrine of normal group wassignificantly shorter than 30ms (-1.61±11.52ms, P＜0.001), while that ofsyncope group was 15.39±25.92ms. The paradoxical QT response(defined as a≥30-ms increase in QT during infusion of＜0.1μg·kg^-1·min^-1 epinephrine) was observed in 6 (26.1%)patients withsyncope but none in normal subjects. A 65ms-QTc increase abovebaseline at any dose were found in more patients than normal subjects(39.1%Vs6.1%, P＜0.001). None was found with a QT_C more than600ms during infusion of any dose in the normal group, while two (8.7%)in the syncope group (P=0.034 for difference). None of the seriousadverse effects were observed in all the subjects obtained in this study.Conclusions Epinephrine is associated with QT_C prolongation, T-wavemorphology changes and amplification of the U-wave in young normalsubjects. The paradoxical QT response (△QT≥30ms at low-dosageepinephrine) or QT_C≥600 ms is highly specific in diagnosis of long-QTsyndrome. Clinical suspected long QT syndrome patients with syncopehad higher positive rate of the former two parametres, which couldprobably do help in the diagnosis of Long QT Syndrome. The graded low-dosage epinephrine stress test is safe and convenient for conduction.