Objective To analyse pulse transit time variability (PTTV) in frequency domain and to study the physiological interpretation of PTTV. Methods Pulse transit time (PTT) was obtained by ECG and PPG (photoplethysmography) from 187 subjects.是什么意思_Objective To analyse pulse transit time variability (PTTV) in frequency domain and to study the physiological interpretation of PTTV. Methods Pulse transit time (PTT) was obtained by ECG and PPG (photoplethysmography) from 187 subjects.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句