Study Protocol for the Pleiotropic Effects of Sodium-Glucose Cotransporter 2 Inhibitor on Organ-Specific Sympathetic Nerve Activity and Insulin Sensitivity in Participants with Type 2 Diabetes.

INTRODUCTION: Hyperinsulinemia and hyperglycemia are associated with exaggerated systemic sympathetic nerve activity (SNA) in patients with type 2 diabetes. Sodium-glucose cotransporter 2 (SGLT2) inhibitors lower insulin levels, whereas sulfonylureas increase insulin levels. We will test whether these two classes of antidiabetic agents have different effects on SNA. METHODS: The present study is an ongoing, 24-week, one-center (only Kanazawa University Hospital), open-label, randomized, parallel trial (jRCTs 041200035). Participants with type 2 diabetes with multiple atherosclerosis risk factors are randomly assigned in a 1:1 manner to receive 2.5 mg luseogliflozin or 0.5 mg glimepiride once daily. The sample size was calculated to be 14 in each group, with a significance level of 0.05 and a power of 0.80. The design required 40 evaluable study participants. Our primary endpoint will be the change in muscle SNA (MSNA). The secondary endpoints included organ-specific insulin sensitivity measured by a hyperinsulinemic-euglycemic clamp study using an artificial pancreas combined with a stable isotope-labeled glucose infusion, bioelectrical impedance analysis, and organ-specific (cardiac, renal, and hepatic) 123I-meta-iodobenzylguanidine (MIBG) innervation imaging. PLANNED OUTCOMES: Study recruitment started in April 2020 and will end in June 2024, with 40 participants randomized into the two groups. The treatment follow-up of the participants is currently ongoing and is due to finish by March 2025. TRIAL REGISTRATION: The study protocol has been approved by the Certified Review Board, Kanazawa University, Ishikawa, Japan, in accordance with the guidelines stipulated in the Declaration of Helsinki (CRB4180005, 2019-001). This trial is registered with the Japan Registry of Clinical Trials, jRCTs 041200035.

Non-Iatrogenic Localized-Reentrant Figure of Eight Atrial Tachycardias in the Superior Vena Cava.

Introduction: The superior vena cava (SVC) is an important non-pulmonary venous foci of atrial fibrillation (AF) and is known as the arrhythmogenic site of scar-related atrial tachycardia (AT). Scar-related ATs may occur after catheter ablation and open heart surgery; however, idiopathic AT rarely occurs. Case Presentation. A 77-year-old male with terminal diabetic nephropathy complained of dialysis-induced hypotension due to AF and was admitted to our hospital for catheter ablation. Here, we report a case of non-iatrogenic localized-reentrant figure of eight AT in the SVC. Conclusion: SVC has the arrhythmogenic potential for re-entrant tachycardia, and the development of mapping technology can reveal arrhythmogenic mechanisms.

Efficacy and safety of tolvaptan in acute heart failure patients during long-distance transportation.

AIMS: Treating patients with acute heart failure is difficult at the local hospitals in medically depopulated areas where cardiologists are generally absent. These patients require long-distance and time-consuming transportation to the intensive care units. It is well known that tolvaptan is effective for the treatment of congestive heart failure, but the effect of prehospital tolvaptan use in patients is not well evaluated. The aim of this study was to evaluate the efficacy and safety of prehospital tolvaptan use in patients with acute congestive heart failure who require long-distance and time-consuming transportation. METHODS: This retrospective study included 30 patients who were newly diagnosed with acute heart failure at Wakkanai City Hospital and transported to Nayoro City General Hospital between January 2013 and May 2020. The patients were classified into those who received tolvaptan (tolvaptan group, n = 18) and did not receive tolvaptan (control group, n = 12). RESULTS: The percentage of patient survival at discharge did not show a statistically significant difference between the groups (100% [tolvaptan] vs. 91% [control], p = 0.414). During transportation, the percentage of patients in the tolvaptan group who required increased oxygen doses was statistically significantly lower than that in the control group (0% vs. 36%, p = 0.0181). Patients in the tolvaptan group had statistically significantly shorter intensive care unit stays (median: 2 days vs. 6 days, p = 0.0376), less days to discontinuation of oxygen (median: 2.8 days vs. 6.9 days, p < 0.00125), and less days to ambulation (median: 1.5 days vs. 7.5 days, p = 0.0362) compared with the control group. In the tolvaptan group, blood pressure was not different; however, heart rate was statistically significantly reduced (99 ± 21 vs. 88 ± 21 beats per minute, p = 0.016) during transportation. CONCLUSION: The use of tolvaptan in patients with acute heart failure requiring long-distance transport is safe and may show better clinical course compared with conventional therapies.