Assessing Accuracy of Wrist-Worn Wearable Devices in Measurement of Paroxysmal Supraventricular Tachycardia Heart Rate

BACKGROUND AND OBJECTIVES: Wrist-worn wearable devices provide heart rate (HR) monitoring function via photoplethysmography technology. Recently, these devices have been used by patients to measure the HR when palpitation occurs, but few validation studies of these instruments have been conducted. We assessed the accuracy of these devices for measuring a HR. METHODS: This study enrolled 51 consecutive patients with a history of paroxysmal supraventricular tachyarrhythmia (SVT) or paroxysmal palpitations who were scheduled to undergo an electrophysiological study (EPS). Three devices were assessed: Apple Watch Series 2 (Apple), Samsung Galaxy Gear S3 (Galaxy), and Fitbit Charge 2 (Fitbit). Patients were randomly assigned to wear 2 different devices. The HR at baseline and induced SVT were measured during the EPS. After successful ablation of SVT, HR measurements was also done during atrial and ventricular pacing study. RESULTS: The mean patient age was 44.4±16.6 years and 27 patients were male (53%). The accuracy (within ±5 beats per minute [bpm] of an electrocardiogram [ECG] measurement) of the baseline HR measurements was 100%, 100%, and 94%, for Apple, Galaxy, and Fitbit, respectively. The HR during induced SVT ranged from 108 bpm to 228 bpm and the accuracy (within ±10 bpm of an ECG) was 100%, 90%, and 87% for the Apple, Galaxy, and Fitbit, respectively. During pacing study, accuracy of these devices was also acceptable but tended to decrease as the HR increased, and showed differences between the devices. CONCLUSIONS: Wrist-worn wearable devices accurately measure baseline and induced SVT HR. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0002282

Mass of Spiral Galaxies by Means of a Maximum Disc Model / Masa de galaxias espirales por medio de un modelo de disco máximo / Massa de galáxias espirais por meio de um modelo de disco máximo

Abstract Maximum disc mass models for a set of spiral galaxies from the Ursa Major Cluster are presented. We construct the models using the Hunther method and the particular solutions are chosen in such a way that the circular velocities are adjusted very accurately to the observed rotation curves of some specific spiral galaxies. Under the maximum disc hypothesis, we consider that the rotation curves of the analyzed galaxies can be modeled with only the contribution of the disc. This implies that it is not necessary to consider the contribution ot the dark matter halo in the inner part of the spiral. In this way, the models reproduce the global behavior of the rotation curves in the great majority of galaxies. Producing good adjustments to calculate the total mass of these galaxies, and yielding values of the order of 1O10 M ☉. Based on the vertical stability criterion presented by Viera & Ramos-caro (2016), we find that all the galaxies analyzed present a vertically stable behavior. On the other hand, from the analysis of the epicyclic frequency we find that all the models exhibit mainly a radial stable behaviour except at the edge of the disc.

Resumen Presentamos modelos de masa de disco máximo para un conjunto de galaxias espirales del Cluster Ursa Major. Los modelos se obtienen por medio del método de Hunter y las soluciones particulares se eligen de tal manera que las velocidades circulares se ajustan muy exactamente a las curvas de rotación observadas de algunas galaxias espirales específicas. Bajo la hipótesis del disco máximo, suponemos que la masa del disco es lo más grande posible, en consonancia con la curva de rotación de la galaxia. Por lo tanto, la contribución de la masa del halo de la materia oscura se considera insignificante en las partes internas de las espirales. Los modelos reproducen la estructura general de las curvas de rotación en la mayoría de las galaxias, proporcionando buenos ajustes para calcular la masa total de estas galaxias obteniendo valores del orden de 1010 M ☉. Basados en el criterio de estabilidad vertical presentado por Vieira and Ramos-Caro (2016), encontramos que todas las galaxias analizadas presentan un comportamiento verticalmente estable. Por otro lado, a partir del análisis de la frecuencia epicíclica se observa que todos los modelos presentaron mayormente un comportamiento estable radial excepto en el borde del disco.

Resumo Apresentamos modelos de massa de disco máximo para um conjunto de galáxias espirais do Cluster Ursa Major. Os modelos são obtidos por meio do método Hunter e as soluções particulares são escolhidas de tal forma que as velocidades circulares são ajustadas com muita precisão às curvas de rotação observadas de algumas galáxias espirais específicas. Sob a hipótese de disco máximo, supomos que a massa do disco é tão grande quanto possível, consistente com a curva de rotação da galáxia. A contribuição de massa do halo da matéria escura é, portanto, assumida como insignificante nas partes internas das espirais. Os modelos reproduzem a estrutura geral das curvas de rotação na maioria das galáxias, proporcionando bons ajustes para calcular a massa total dessas galáxias obtendo valores da ordem de 1010 M ☉. Com base no critério de estabilidade vertical apresentado por Vieira and Ramos-Caro (2016), descobrimos que todas as galáxias analisadas apresentam um comportamento verticalmente estável. Por outro lado, a partir da análise da frequência epicíclica, descobrimos que todos os modelos apresentaram principalmente um comportamento estável radial, exceto na borda do disco.

Analysis of Factors Affecting Output Levels and Frequencies of MP3 Players

Exposure to high levels of music that could lead to music induced hearing loss (MIHL) has been of recent interest especially for young adults, considering their excessive use of personal listening devices such as MP3 player. More attention should be drawn to MIHL for noting that early noise exposure leads to earlier onset of presbycusis. In search of appropriate and safe listening habits for young adults, this investigation was aimed to evaluate output levels and frequencies generated by the Samsung galaxy note MP3 player depending on two earphone types; ear-bud and over-the-ear earphones and three music genres; rock, hip-hop, ballade. A sound level meter was used to measure output level and frequency spectrum between 12.5 and 16000 Hz at all 1/3-octave bands. The following results can be summarized. 1) The earphone styles did not produce significant difference in output levels, but the music genres did. However, the results of music genres varied. 2) Neither earphone styles nor music genres produced significant difference in frequency response spectrum, except music genres at the volume settings we usually listen to. Additionally, volume levels should be lower than 50% for usual listening situation. Through this investigation, it was noted that the frequency range was substantial between 50 and 1000 Hz regardless of the styles of earphones and music genres, implying that we should be cautious of this frequency range when we listen to music. Researchers should give more attention to the effects of the mixture of output level and frequency spectrum, considering that the auditory system has frequency specificity from the periphery to the central to provide refined methods for protecting our ears from MIHL.