Castiglioni Paolo, Meriggi Paolo, Rizzo Francesco, Vaini Emanuele, Faini Andrea, Parati Gianfranco, Merati Giampiero, Di Rienzo Marco
Fondazione Don C. Gnocchi, Milan, Italy.
Annu Int Conf IEEE Eng Med Biol Soc. 2011;2011:4283-6. doi: 10.1109/IEMBS.2011.6091063.
Seismocardiography is the body-surface recording of vibrations produced by the beating heart. A high frequency (HF) accelerometric component of the seismocardiogram (SCG) is related to the heart sounds generated by the closure of atrio-ventricular and semilunar valves. This paper evaluates the feasibility of recording the SCG component associated to cardiac sounds by means of a wearable device originally designed for monitoring ECG, respiratory movements, body accelerations and posture in freely moving subjects. The method is based on the averaging of the HF component of the acceleration vector measured by the wearable system, and on the subsequent extraction of features from its envelope. The method is applied on data recorded in healthy volunteers in different postures and during sleep. Results indicate that it is possible to reliably identify the time of occurrence of the first and second heart sound within the cardiac cycle. They also show significant differences in the HF component of SCG between supine and standing postures. Analyzing the HF SCG in a volunteer sleeping at high altitude (4554 m asl) substantial differences were also found among three body positions (lying supine or on the left or right side). These differences are likely to reflect changes in cardiac mechanics induced by different postures of the body.
地震心音描记术是对心脏跳动产生的振动进行体表记录。地震心音图（SCG）的高频（HF）加速度计成分与房室瓣和半月瓣关闭产生的心音有关。本文评估了通过一种最初设计用于监测自由活动受试者的心电图、呼吸运动、身体加速度和姿势的可穿戴设备来记录与心音相关的SCG成分的可行性。该方法基于可穿戴系统测量的加速度矢量的高频成分的平均化，以及随后从其包络中提取特征。该方法应用于健康志愿者在不同姿势和睡眠期间记录的数据。结果表明，有可能在心动周期内可靠地识别第一心音和第二心音的出现时间。结果还显示，仰卧位和站立位之间SCG的高频成分存在显著差异。分析一名在高海拔（海拔4554米）睡眠的志愿者的高频SCG，发现三个身体姿势（仰卧或左侧或右侧卧位）之间也存在显著差异。这些差异可能反映了身体不同姿势引起的心脏力学变化。
