IEEE J Biomed Health Inform. 2018 Jan;22(1):129-139. doi: 10.1109/JBHI.2017.2731790. Epub 2017 Jul 25.
The estimation of systolic time intervals (STIs) is done using continuous wave (CW) radar at 2.45 GHz with an on-body antenna.
In the state of the art, typically bioimpedance, heart sounds and/or ultrasound are used to measure STIs. All three methods suffer from insufficient accuracy of STI estimation due to various reasons. CW radar is investigated for its ability to overcome the deficiencies in the state of the art.
Ten healthy male subjects aged 25-45 were asked to lie down at a 30 incline. Recordings of 60 s were taken without breathing and with paced breathing. Heart sounds, electrocardiogram, respiration, and impedance cardiogram were measured simultaneously as reference. The radar antennas were placed at two positions on the chest. The antennas were placed directly on the body as well as with cotton textile in between. The beat to beat STIs have been determined from the reference signals as well as CW radar signals.
The results indicate that CW radar can be used to estimate STIs in ambulatory monitoring.
The results pave way to a potentially more compact method of estimating STIs, which can be integrated into a wearable device.
使用 2.45GHz 的连续波 (CW) 雷达和体上天线来估计收缩时间间隔 (STI)。
在现有技术中，通常使用生物阻抗、心音和/或超声来测量 STI。由于各种原因，这三种方法都存在 STI 估计精度不足的问题。CW 雷达因其能够克服现有技术的缺陷而受到研究。
要求 10 名年龄在 25-45 岁的健康男性受试者以 30 度的倾斜度躺下。在不呼吸和有节奏呼吸的情况下进行 60 秒的记录。同时测量心音、心电图、呼吸和阻抗心动图作为参考。雷达天线放置在胸部的两个位置。天线直接放在身体上，中间夹着棉纺织品。从参考信号和 CW 雷达信号中确定逐拍 STI。
结果表明 CW 雷达可用于在动态监测中估计 STI。
这些结果为估计 STI 的一种潜在更紧凑的方法铺平了道路，该方法可集成到可穿戴设备中。
