Jong Il Choi

Total and interatrial epicardial adipose tissues are independently associated with left atrial remodeling in patients with atrial fibrillation.

Epicardial Adipose Tissue in Atrial Fibrillation. Introduction: As epicardial adipose tissue (EAT) is a metabolically active visceral fat, potential interaction between EAT and myocardium is strongly suggested. The aims of this study were to determine whether the amount and regional distribution of EAT are related to the chronicity of atrial fibrillation (AF) and left atrial (LA) remodeling.

Safety and Convenience of Continuous Warfarin Strategy During the Periprocedural Period in Patients Who Underwent Catheter Ablation of Atrial Fibrillation

Continuous Warfarin Before AF Ablation. Background: We investigated the efficiency and convenience of a continuous warfarinization (CW) strategy during the periprocedural period of radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) in comparison with the classic strategy of switching to heparin (SH).

Effect of fucoidan on aspirin-induced stomach ulceration in rats

In this study, the effects of fucoidan on aspirin-induced ulcers in rats were evaluated: both biochemical and immunological parameters were taken into consideration. The status of stomach tissue glycogen storage and histological changes were also examined. Examination of basic biochemical parameters showed significant (p<0.01) alterations in aspartate (AST) and alanine (ALT) transaminases in ulcer-induced rats. Also, moderate alterations (p<0.05) were observed in the levels of cholesterol and blood urea nitrogen (BUN). Histopathological examination showed neutrophil infiltration and inflammation in oxyntic cells with altered glycogen storage. Analysis of serum cytokines of aspirin-induced rats showed a moderate decrease in interleukin-10 (IL-10) with considerable increase of interleukin-6 (IL-6) and interferon-gamma (INF-gamma) when compared with control. Administration of fucoidan showed considerable (p<0.05) protection against ulceration by inhibiting the acute alterations of AST, ALT, cytokines and stomach glycogen. However, aggravated serum INF-gamma was observed in the fucoidan-pretreated group. These findings suggest that the anti-ulcer property of fucoidan might contribute in protecting the inflammatory cytokine-mediated oxidative damage to gastric mucosa.

Electrocardiographic and electrophysiological characteristics of premature ventricular complexes associated with left ventricular dysfunction in patients without structural heart disease

AIMS The mechanism responsible for premature ventricular complex (PVC)-mediated left ventricular (LV) dysfunction remains unclear. We sought to determine the electrocardiographic and electrophysiological characteristics of PVC-mediated LV dysfunction. METHODS AND RESULTS One hundred and twenty-seven patients who underwent radiofrequency catheter ablation (RFCA) for frequent PVCs (PVCs burden ≥10%/24 h) and had no significant structural heart disease were investigated. Left ventricular dysfunction (ejection fraction < 50%) was present in 28 of 127 patients (22.0%). The mean PVC burden (31 ± 11 vs. 22 ± 10%, P < 0.001), the presence of non-sustained ventricular tachycardia (53.6 vs. 33.3%, P = 0.05), and the presence of a retrograde P-wave following a PVC (64.3 vs. 30.3%, P = 0.001) were significantly greater in those with LV dysfunction than in those with normal LV function. The cut-off PVC burden related to LV dysfunction was 26%/day, with a sensitivity of 70% and a specificity of 78%. The PVC morphology, QRS axis, QRS width, coupling interval, the presence of interpolation, and PVC emergence pattern during exercise electrocardiogram were not significantly different between the two groups. The origin sites of PVCs, the acute success rate, and the recurrence rate during follow-up after RFCA were similar. In a multivariate analysis, the PVC burden (odds ratio 2.94, 95% confidence interval 0.90-3.19, P = 0.006) and the presence of retrograde P-waves (odds ratio 2.79, 95% confidence interval 1.08-7.19, P = 0.034) were independently associated with PVC-mediated LV dysfunction. CONCLUSION A higher PVC burden (>26%/day) and the presence of retrograde P-waves were independently associated with PVC-mediated LV dysfunction.

Structural feature and antioxidant activity of low molecular weight laminarin degraded by gamma irradiation

Recently, it has been reported that low molecular weight laminarin had enhanced biological activities. In this study, laminarin was degraded by gamma irradiation, and the changes in its structure and antioxidant property were investigated. Gel permeation chromatography data showed that the average molecular weight of the irradiated laminarin decreased significantly as the irradiation dose increased. The absorbance at 290nm, from UV spectra, was increased, depending on the irradiation dose and caused by the formation of carbonyl groups. From the NMR analysis, the ratio of β-1,3- to β-1,6-linkages was not changed, indicating the random scission of chains by gamma irradiation. The antioxidative activities, measured by Rancimat test, were all increased in the gamma-irradiated laminarin, depending on the absorbed dose, presumably due to the carbonyl groups formed by gamma irradiation. Therefore, gamma irradiation could be a promising method for preparing low molecular weight laminarin with enhanced biological activities.

Improved endothelial function in patients with atrial fibrillation through maintenance of sinus rhythm by successful catheter ablation.

Effect of Ablation on Endothelial Function. Background: Although atrial fibrillation (AF) is a risk factor for endothelial dysfunction (ED), the effect of catheter ablation (CA) on AF‐associated ED has not been evaluated. The aims of this study are to determine if the degree of ED predicts the outcome of AF ablation and to evaluate whether ED can be improved through restoring sinus rhythm (SR) by successful CA.

The relationship between endocardial voltage and regional volume in electroanatomical remodeled left atria in patients with atrial fibrillation: comparison of three-dimensional computed tomographic images and voltage mapping.

Background: Long‐standing atrial fibrillation (AF) changes left atrial (LA) morphology, and the LA size is related to recurrence after radiofrequency catheter ablation (RFCA). We hypothesize that LA morphology, based on embryological origin, affects the outcome of RFCA.

Clinical Significance of Early Recurrences of Atrial Tachycardia After Atrial Fibrillation Ablation

Early Recurrence After AF Ablation. Background: Atrial tachycardia (AT) commonly recurs within 3 months after radiofrequency catheter ablation for atrial fibrillation (AF). However, it remains unclear whether early recurrence of atrial tachycardia (ERAT) predicts late recurrence of AF or AT.

Application of gamma irradiation for the enhanced physiological properties of polysaccharides from seaweeds.

Polysaccharides from seaweeds, fucoidan and laminarin, were irradiated with gamma rays, and their structural changes and anti-oxidative activities were investigated. The gamma irradiation decreased the average molecular weights of polysaccharides, and UV spectra of irradiated polysaccharides showed increases in the numbers of carboxyl and carbonyl groups and double bonds. DPPH radical scavenging ability and reducing power of the gamma irradiated polysaccharides were significantly higher than those non-irradiated.

Left Atrial Electromechanical Conduction Time Can Predict Six-Month Maintenance of Sinus Rhythm After Electrical Cardioversion in Persistent Atrial Fibrillation by Doppler Tissue Echocardiography

BACKGROUND The purpose of this study was to determine whether atrial electromechanical conduction time (EMT) measured by echocardiography can predict 6-month maintenance of sinus rhythm (SR) after electrical cardioversion in patients with atrial fibrillation (AF). METHODS Fifty-three patients with persistent AF (>1 month) who had successful cardioversion and 30 controls with SR were prospectively enrolled. SR maintenance was assessed during 6-month follow-up. EMT was measured as the time interval from the onset of the P wave on electrocardiography to the peak of the late diastolic wave from the septal and lateral mitral annulus (EMT-S and EMT-L, respectively) and the lateral tricuspid annulus (EMT-T) on tissue Doppler echocardiography. RESULTS Compared with controls, left atrial (LA) volume index, P-wave duration, and EMT were significantly larger in patients with AF (all P values<.001). In patients with AF, the duration of AF (P=.71) and P-wave duration (P=.24) were not different between the SR maintenance group (n=23) and the AF recurrence group (n=30), and there was a trend toward increased LA volume index in the AF recurrence group (47.0+/-12.4 vs 45.3+/-12.6 mL/m2, P=.07). EMT-S and EMT-L were significantly larger in the AF recurrence group (131.4+/-20.9 vs 116.3+/-15.5 ms, P=.005, and 152.2+/-15.7 vs 128.9+/-13.8 ms, P<.001, respectively), but not EMT-T. EMT-S and EMT-L were related to LA volume index (r=.36, P=.008, and r=.33, P=.02, respectively). On multivariate logistic regression analysis, only EMT-L was an independent predictor of identifying patients who remained in SR (P<.001), and the sensitivity and specificity for the prediction of 6-month maintenance of restored SR were 82.6% and 83.3% using a cutoff value of EMT-L<or=138.0 ms (odds ratio, 0.862; 95% confidence interval, 0.788-0.942; P=.001). CONCLUSION LA EMT was significantly prolonged in patients with recurring AF, indicating significantly depressed atrial conduction in enlarged LA, and can predict 6-month maintenance of SR after electrical cardioversion.