We evaluated the accuracy of a 24-hr ambulatory blood pressure monitoring (ABPM) device with a new irregular heartbeat (IHB) algorithm for detecting atrial fibrillation (AF) during each BP ...measurement. Ninety patients with a history of elevated BP and some type of arrhythmia (mean age 63.2 ± 10.3 years; 94% with hypertension; 81% with previously diagnosed AF) simultaneously underwent evaluation by 24-hr ABPM with the IHB algorithm and 24-hr Holter electrocardiography (ECG). Among the 3,347 valid readings, 843 readings were considered to indicate an IHB. Among these IHB readings, 195 readings were found to have an AF rhythm by 24-hr Holter ECG. The IHB algorithm showed 100% sensitivity and 79.4% specificity for accurately detecting AF rhythm. An IHB was detected in 12.1% of the measurements during normal rhythm, 48.8% of those during atrial premature complex, and 54.4% of those during ventricular premature complex. The percentage of IHBs detected during normal rhythm was higher in the daytime than at nighttime (16.3% vs. 4.5%, respectively), suggesting that daytime physical activity sometimes induces a false detection of IHBs. The optimal IHB parameters for suggesting potential AF were (1) an IHB burden defined as a percentage of IHB-positive readings in total valid BP measurements >22.5% (84.6% sensitivity, 85.1% specificity; AUC 0.906, p < 0.0001) and (2) 2.5 or more consecutive IHBs during 24-hr ABPM (84.6% sensitivity, 83.0% specificity; AUC 0.881, p < 0.0001). The novel 24-hr ABPM device with the IHB algorithm assessed herein could contribute to the future comprehensive management of hypertensive patients, with the main goal of preventing cerebrovascular events.
Superconducting magnetic energy storage (SMES) can provide high efficiency, longevity, and instantaneous response with high power. However, its energy storage density is extremely low. To address ...this drawback, the use of a no-insulation (NI) REBCO coil has been considered. NI coils are expected to achieve high current density as well as high thermal stability, and the energy storage density can be improved by applying these coils to SMES. However, Joule loss occurs owing to the current flow in the radial direction through the contact electrical resistance between turns during charging and discharging. Because the amount of loss depends on the contact electrical resistance, it is necessary to adjust the resistance to an appropriate value to make the storage efficiency a practical value. In this study, we conduct experiments to investigate the behavior of small-scale NI-REBCO coils with different contact electrical resistances considering the charge/discharge current pattern for actual SMES operation. In addition, numerical simulations are performed using the partial element equivalent circuit (PEEC) model under the same conditions as those used in the experiment, and the reproducibility of the experimental results is confirmed. Finally, using the PEEC model, numerical simulations are performed assuming an m-class coil. The relationship between the storage efficiency and the contact electrical resistance, which is an important indicator for applying NI coil technology to SMES, is clarified by the results.
Superconducting magnetic energy storage (SMES) has the advantages of high efficiency, longevity, and excellent instantaneous response with high power. However, it has the disadvantage of having a ...very low energy storage density in comparison to other power storage devices. The no-insulation coil (NI coil) is expected to be a winding method capable of achieving both high current density and high thermal stability. It is predicted that if this NI coil technology can be used for SMES, it will be possible to improve energy storage density by achieving higher current density. Because the SMES is a power device, it is generally preferred for coils to be designed with high current and low inductance. Therefore, in this study, we considered adopting the winding method in which a bundle conductor using of multiple no-insulation REBCO tapes is wound without electrical insulation (hereinafter referred to as "bundle NI coil") for SMES coils. However, because the REBCO tapes in the bundle conductors are not electrically insulated from one another and the bundles also have no electrical insulation between one another, the time variation of the current distribution in the bundle NI coil becomes extremely complicated. Therefore, we developed a computer program that analyzes and evaluates the current distribution in a bundle NI coil, and for application to SMES, we numerically investigated the behavior during charge and discharge of a coil wound with a no-insulation bundle REBCO conductor. Furthermore, a small bundle NI coil was constructed and tested to confirm the validity of the developed computer program, and the time variation of the current distribution in the bundle conductor was based on the analysis results. In addition, the effect of the NI bundle coil on the storage efficiency when used to SMES was investigated experimentally and numerically.
Few data are available on gastric hypomotility (GH) after cryoballoon pulmonary vein isolation. Also, the use of esophageal temperature monitoring for the prevention of endoscopically detected ...esophageal lesions (EDELs) is not well established.
The purpose of this study was to investigate GH and the impact of an esophageal probe on EDELs during second-generation cryoballoon ablation.
One hundred four patients with paroxysmal atrial fibrillation undergoing second-generation cryoballoon ablation under conscious sedation followed by esophagogastroscopy were prospectively included. Temperature probes were used in the first 40 (38.5%) patients, but not in the latter 64 (61.5%). Pulmonary vein isolation was performed with one 28-mm balloon using single 3-minute freeze techniques.
Clinical and procedural characteristics were similar between the groups. Esophagogastroscopy 1.4 ± 0.5 days postablation demonstrated GH and EDELs in 18 (17.3%) and 9 (8.7%) patients. The incidence of GH was similar (7 of 40 vs 11 of 64; P = .967) between the groups, while that of EDELs was significantly higher in the former than in the latter group (8 of 40 vs 1 of 64; P < .0001). In multivariate analyses, the esophagus-right inferior pulmonary vein ostium distance (hazard ratio 0.870; 95% confidence interval 0.798-0.948; P = .002) was the sole predictor of GH, and the optimal cutoff for the prediction was 18.2 mm (sensitivity 88.1%; specificity 77.8%). The use of esophageal probes was the sole predictor of EDELs (hazard ratio 15.750; 95% confidence interval 1.887-131.471; P = .011). All collateral damage was asymptomatic and healed on repeat esophagogastroscopy at a mean of 2 ± 1 months postprocedure.
Second-generation cryoballoon ablation is associated with an increased incidence of silent periesophageal nerve injury even using short freeze times, and anatomical information aids identifying high-risk populations. The use of esophageal probes increases the risk of EDELs.
In order to achieve a high intensity and compact multifunctional air-core cyclotron, the behavior of non-circular coils in a high magnetic field at 4.2 K were investigated. Two types of isosceles ...triangle shaped double-pancake coils: a coil with reinforcement by Yoroi-coil (Y-based oxide superconductor and reinforcing outer integrated coil) structuring and a coil without reinforcement, were manufactured and their behaviors were observed when current was applied to each coil in a high magnetic field. The non-reinforcement coil showed in 10 T external magnetic field that the superconducting properties of the coil were partially lost and a voltage generated in the coil winding was observed when the applied current exceeded 160 A. After disassembling this coil, it was found that the superconducting tape in the coil winding was plastically deformed and permanently bent at the corners. The reinforced coil due to Yoroi-coil structuring was powered up to the coil current of 300 A in a magnetic field of 14 T. A voltage of 0.3 mV was observed when the coil current was 277 A, and the excitation was terminated when the voltage reached 0.6 mV at 300 A. The coil winding, after the current flowing up to 300 A in 14 T field, indicated that the deformation of it was significantly limited. It was confirmed that the Yoroi-coil type structural reinforcement, even for triangular coils, has sufficient mechanical strength under the conditions of our air-core cyclotron.
PDF
