Early detection of cardiac involvement in sarcoidosis is difficult but important to achieve optimal treatment. Signal-averaged electrocardiography（SAECG）can detect subtle cardiac electrical abnormalities known as late potentials（LPs）and would be useful for the early diagnosis of cardiac involvement. We prospectively studied 74 patients with pulmonary sarcoidosis without overt electrocardiographic abnormalities. All participants underwent SAECG, cardiac echocardiography, and 24-hour ambulatory Holter monitoring. Serum angiotensin-converting enzyme and B-type natriuretic peptide levels were also evalusated. We followed up these patients to evaluate the incidence of cardiac events including cardiac death, arrhythmias, and heart failure requiring hospital admission. Of the studied population, 29 patients（39.2％）had detectable LP. During a mean follow-up period of 9.8 years, 8 patients with LPs had cardiovascular events, including development of complete atrioventricular block（n＝4）, ventricular tachycardia（n＝2）, and heart failure（n＝2）. Only 1 of 45 patients without LP developed cardiac event（heart failure）. Multivariate analyses revealed that LPs were associated with an increased risk of developing cardiac events（hazard ratio 9.66 ; 95％ confidence interval 1.20-78.01 ; p＝.033）whereas age, sex, serum angiotensin-converting enzyme and B-type natriuretic peptide levels, number of premature ventricular contractions on 24-hour Holter monitoring, and echocardiographic parameters were not associated with subsequent cardiac events. SAECG may be useful for the early detection of cardiac sarcoidosis and could be used as a screening test for further risk stratification.

Background : Obesity, characterized by systemic low-grade inflammation, is considered a well-known risk for atrial fibrillation. In fact, interleukin 10（IL-10）, which is a potent anti-inflammatory cytokine, has been reported to decrease in obese and diabetic patients. We tested the hypothesis that genetic deletion of IL-10 exacerbates high-fat diet（HFD）–induced obesity-caused atrial inflammation, lipidosis, fibrosis, and fibrillation and that IL-10 therapy inhibits this pathology. Methods : Eight- to 10-week-old male CL57/B6（wild-type）mice and IL-10 knockout mice were divided into a 12-week HFD group and a 12-week normal-fat diet（NFD）group, respectively. The effect of IL-10 administration was also investigated. Results : HFD-induced obesity for 12 weeks significantly depressed serum levels of IL-10 but were found to increase several proinflammatory cytokines in wild-type mice. Adverse atrial remodeling, including atrial inflammation, lipidosis, and fibrosis, was induced in both wild-type and IL-10 knockout mice by HFD. Vulnerability to atrial fibrillation was also significantly increased by HFD. The total amount of epicardial adipose tissue＋pericardial adipose tissue volume was increased by HFD. Proinflammatory and profibrotic cytokines of epicardial adipose tissue＋pericardial adipose tissue were also upregulated. In contrast, the protein level of adiponectin was downregulated by HFD. These HFD-induced obesity-caused adverse effects were further exaggerated in IL-10 knockout mice in comparison to wild-type mice. Systemic IL-10 administration markedly ameliorated HFD-induced obesity-caused left atrial remodeling and vulnerability to atrial fibrillation, in addition to improving the quality of epicardial adipose tissue＋pericardial adipose tissue. Conclusions : Our results highlight IL-10 treatment as a potential therapeutic approach to limit the progression of HFD-induced obesity-caused atrial fibrillation.

Background : The recommended implantation site and direction of the Reveal LINQ Insertable cardiac monitor（Medtronic Inc, Minneapolis, Minnesota）is the left 4th intercostal space in an oblique direction. However, the feasibility of the recommended implantation site and direction has not been fully investigated. The purpose of this study was to investigate the optimal positioning of the Reveal LINQ. Methods : From September 2017 to June 2019, 25 patients scheduled to be implanted with a Reveal LINQ were studied. The QRS amplitudes of the body surface ECG at each site and direction were measured. Measurements sites were the 3rd, 4th, and 5th intercostal spaces. The measurements were in the vertical, horizontal, and oblique directions. Therefore, a total of nine QRS amplitudes were measured for each patient. After mapping, the Reveal LINQ was implanted in the maximum QRS amplitude site and direction. The preprocedural body surface QRS amplitude and postoperative QRS amplitude measured by the Reveal LINQ were compared. Results : The preprocedural body surface QRS amplitude and postoperative QRS amplitude were well correlated. The maximum QRS amplitude was obtained at the recommended implantation site and direction in only 13 patients（52％）. Conclusion : Preprocedural QRS amplitude mapping was useful to determine the optimal implantation site and direction. The recommended site and direction were not always the optimal site and direction.