Assessment of autonomic nervous system modulation after novel catheter ablation techniques for atrial fibrillation using multiple short-term electrocardiogram recordings

Purpose

The effect of novel catheter ablation techniques for atrial fibrillation (AF) on the autonomic nervous system (ANS) is unclear. This study aimed to assess the ANS after three novel catheter ablation techniques for paroxysmal AF by evaluating heart rate variability (HRV) parameters using a 3-min electrocardiogram recording.

Methods

Two hundred and thirty-five patients who underwent catheter ablation for paroxysmal AF (119 in irrigated-tip, 51 in contact-force sensing-guided, and 65 patients in second-generation cryoballoon ablation) were included. HRV analysis was performed at baseline and 1, 3, 6, and 12 months after the ablation.

Results

The three ablation groups had similarly decreased HRV parameters after the ablation, and this change was maintained > 1 year. A reduction in parasympathetic nervous function was more apparent after the ablation, compared to changes in the sympathetic nervous function. Of the total population, 45 patients had recurrence. Ln high frequency (HF) 12 months after the ablation was significantly higher in the recurrence group than in the non-recurrence group (1.52 ± 0.47 vs. 1.26 ± 0.57 ms², p = 0.007). Multivariate analysis demonstrated that AF duration (hazards ratio 1.09, 95% confidence interval 1.04–1.15, p = 0.001) and ln HF 12 months after ablation (hazards ratio 1.91, 95% confidence interval 1.12–3.25, p = 0.017) were independent predictors of AF recurrence after the ablation.

Conclusions

ANS modulation after the three catheter ablation methods was similar and maintained > 1 year after the procedure. Higher parasympathetic nervous function at 1 year after ablation was associated with AF recurrence after the ablation.

     

Clinical characteristics of autoimmune hepatitis in older aged patients.

BACKGROUND AND AIMS: Autoimmune hepatitis (AIH) is an inflammatory disease of the liver that usually develops in middle-aged women. However, due to the increasing aging of the population and better diagnostic facilities, AIH is now diagnosed in older patients as well. This analysis compared the clinical and pathologic characteristics of older and middle-aged patients with AIH. PATIENTS AND METHODS: Thirteen older patients with AIH (mean age, 75.0+/-5.3 years; range, 70-89 years) and 27 middle-aged patients (mean age, 51.3+/-5.8 years; range, 41-60 years) were included in this study. In addition, the use of different treatment regimens, including prednisolone therapy and ursodeoxycholic acid (UDCA), was examined. RESULTS: There were no significant differences in gender, complications of other autoimmune diseases, and liver function tests between groups. However, the degree of hepatic fibrosis was significantly higher in older patients compared with middle-aged patients (P<0.05). Four patients with AIH in the older age group were successfully managed by UDCA alone. CONCLUSION: This study shows that older patients with abnormal liver function should be checked for AIH. In addition, UDCA may be an effective drug for management of older patients with AIH.     

Surgical technique influences bowel function after low anterior resection and sigmoid colectomy

BACKGROUND/AIMS: Since June 1996, we have changed surgical strategies to preserve the pelvic autonomic nerve and abandon high ligation of the inferior mesenteric artery. The aim of this study was to clarify the influence of this surgical technique on subjective bowel function of patients with low anterior resection and sigmoid colectomy for cancer. METHODOLOGY: Forty-eight patients who underwent low anterior resection or sigmoid colectomy for cancer during June 1996 and February 2000 replied to the questionnaire which consisted of eight categories of bowel symptoms. Subjective bowel function and operative data of these patients were compared with those obtained from 84 patients with low anterior resection or sigmoid colectomy during April 1984 and May 1996. RESULTS: When recent series were compared with previous series, the frequency of bowel movement at night (21% vs. 60%, p < 0.01) and patient's own judgment as fair or poor (0% vs. 29%, p < 0.01) was decreased in patients with low anterior resection; whereas the frequency of defecation > 2 per day (5% vs. 34%, p < 0.01), difficulty in emptying (32% vs. 71%, p < 0.01), and incomplete evacuation (32% vs. 66%, p < 0.05) was decreased in patients with sigmoid colectomy. Patient judged as poor bowel function was less frequent in the recent group after low anterior resection (25% vs. 71%, p < 0.01) and sigmoid colectomy (18% vs. 42%, p < 0.05) compared with the previous group. Operative data including volume of blood loss, frequency of transfusion, and length of resected specimen were also different between the two groups. CONCLUSIONS: Surgical technique had a significant impact on bowel function following low anterior resection and sigmoid colectomy for cancer. When high ligation of the inferior mesenteric artery is abandoned and the pelvic autonomic nerve is preserved by careful technique, postoperative bowel dysfunction in patients with rectosigmoid colon cancer can be minimized.     

Lipoprotein lipase activator NO-1886 (ibrolipim) accelerates the mRNA expression of fatty acid oxidation-related enzymes in rat liver

The lipoprotein lipase (LPL) activator NO-1886 (ibrolipim) has been shown to have potential benefits for the treatment of obesity in rats. However, the anti-obesity mechanism of NO-1886 has not been clearly understood. To address this, we studied the effects of NO-1886 on the mRNA expression of fatty acid oxidation-related enzymes in rats. The respiratory quotient (RQ) in rats administered a single oral dose of NO-1886 was significantly lower than control rats under both fed and fasted conditions. NO-1886 orally administered to rats for 7 days caused 1.54-fold increase in carnitine palmitoyl transferase II (CPTII) mRNA in the carnitine palmitoyl transferase system. Furthermore, NO-1886 caused a 1.47-fold increase in long-chain acyl-CoA dehydrogenase (LCAD) mRNA, a 1.49-fold increase in acetyl-CoA acyltransferase 2 (ACAA2) mRNA, and a 1.24-fold increase in enoyl-CoA hydratase (ECH) mRNA in rats, all which are liver beta-oxidation enzymes. NO-1886 also increased uncoupling protein-2 (UCP2) mRNA levels in liver by 1.42-fold when compared to the control group. These results suggest that the LPL activator NO-1886 may accelerate the expression of fatty acid oxidation-related enzymes, resulting in a reduction of RQ.     

Diagnostic implications of modified treadmill and head-up tilt tests in exercise-related syncope: comparative studies with situational and/or vasovagal syncope

BACKGROUND: The precise pathophysiological basis of exercise-related vasodepressor syncope is not well understood. Purpose: The diagnostic values of head-up tilt and modified treadmill tests with abrupt termination were tested in patients with exercise-related syncope and compared with those of patients with situational or vasovagal syncope. PATIENTS AND METHODS: Diagnostic accuracies of head-up tilt and modified treadmill exercise tests were examined in 44 patients with unexplained syncope (26 men, 18 women, aged 46 19 years) and in 20 control subjects. Results for 18 patients with syncope during exercise (short-distance dash [n=7], jogging [n=3], going up stairs [n=6], swimming [n=1] or cycling [n=1]), defined as exercise-related syncope, were compared with those for 26 patients with exercise-unrelated syncope (including situational [n=7] and vasovagal [n=14] syncope). RESULTS: No differences were found between the clinical backgrounds of subjects with and those without exercise-related syncope. Head-up tilt testing had good diagnostic sensitivities, specificities and accuracies in both exercise-related and exercise-unrelated groups (84% versus 77%, 84% versus 85%, 84% versus 80%, respectively). The corresponding values of modified treadmill tests in the two groups were 78% versus 19% (P<0.05), 95% versus 95% and 86% versus 52% (P<0.05), respectively. The results of exercise tests were of limited diagnostic value for exercise-unrelated syncope. Beta-blockade had good short term efficacy in subjects with exercise-related syncope (nine of 15, 60%) as well as in subjects with exercise-unrelated syncope (seven of 10, 70%). CONCLUSIONS: Modified treadmill exercise testing is thought to be useful for diagnosing exercise-related syncope.     

Comparison of prevalence of apical hypertrophic cardiomyopathy in Japan and the United States

The morphologic apical form of hypertrophic cardiomyopathy (HC), in which left ventricular (LV) wall thickening is confined to the most distal region at the apex, has been regarded as a phenotypic expression of nonobstructive HC largely unique to Japanese patients. To investigate this question further, we directly compared unselected and regional hospital-based cohorts of adult patients with HC ( > or =18 years of age) from Japan (Kochi; n=100) and from the United States (US) (Minneapolis; n=361). Japanese and American patients with HC had similar clinical features and did not differ significantly with regard to the severity of symptoms and frequency of outflow obstruction. Although Japanese and American patients also showed similar maximum LV thickness, they differed significantly with respect to the distribution of LV hypertrophy. In particular, the segmental form of HC, with hypertrophy confined to the LV apex, was more frequent in Japanese patients (i.e., apical HC, 15% in Japan vs 3% in US, p<0.0001). Giant negative T waves were also more common in Japanese patients with HC (26% vs 2%, p<0.001), including those with the apical form (64% vs. 30%, p<0.05). Each patient with apical HC had either no or only mild symptoms, and all survived. The morphologic form of nonobstructive HC with hypertrophy limited to the LV apex (apical form of HC) was 5 times more common in an unselected Japanese population. These findings document variability in the phenotypic expression of HC between countries and races, which may be due to differences in environmental factors or genetic background. Patients with the apical form of HC had a benign clinical course.     

Inhibition of glucose-stimulated insulin secretion by KCNJ15, a newly identified susceptibility gene for type 2 diabetes

Potassium inwardly rectifying channel, subfamily J, member 15 (KCNJ15) is a type 2 diabetes-associated risk gene, and Kcnj15 overexpression suppresses insulin secretion in rat insulinoma (INS1) cells. The aim of the current study was to characterize the role of Kcnj15 by knockdown of this gene in vitro and in vivo. Human islet cells were used to determine the expression of KCNJ15. Expression of KCNJ15 mRNA in islets was higher in subjects with type 2 diabetes. In INS1 cells, Kcnj15 expression was induced by high glucose-containing medium. Regulation of Kcnj15 by glucose and its effect on insulin secretion were analyzed in INS1 cells and in normal mice and diabetic mice by the inactivation of Kcnj15 using small interfering RNA. Knockdown of Kcnj15 increased the insulin secretion in vitro and in vivo. KCNJ15 and Ca(2+)-sensing receptor (CsR) interact in the kidney. Binding of Kcnj15 with CsR was also detected in INS1 cells. In conclusion, downregulation of Kcnj15 leads to increased insulin secretion in vitro and in vivo. The mechanism to regulate insulin secretion involves KCNJ15 and CsR.