Davidson Shaun, Pretty Chris, Pironet Antoine, Kamoi Shun, Balmer Joel, Desaive Thomas, Chase J Geoffrey
Department of Mechanical Engineering, University of Canterbury, Christchurch, New Zealand.
GIGA-Cardiovascular Sciences, University of Liège, Liège, Belgium.
Biomed Eng Online. 2017 Apr 13;16(1):42. doi: 10.1186/s12938-017-0338-7.
The aim of this paper was to establish a minimally invasive method for deriving the left ventricular time varying elastance (TVE) curve beat-by-beat, the monitoring of which's inter-beat evolution could add significant new data and insight to improve diagnosis and treatment. The method developed uses the clinically available inputs of aortic pressure, heart rate and baseline end-systolic volume (via echocardiography) to determine the outputs of left ventricular pressure, volume and dead space volume, and thus the TVE curve. This approach avoids directly assuming the shape of the TVE curve, allowing more effective capture of intra- and inter-patient variability.
The resulting TVE curve was experimentally validated against the TVE curve as derived from experimentally measured left ventricular pressure and volume in animal models, a data set encompassing 46,318 heartbeats across 5 Piétrain pigs. This simulated TVE curve was able to effectively approximate the measured TVE curve, with an overall median absolute error of 11.4% and overall median signed error of -2.5%.
The use of clinically available inputs means there is potential for real-time implementation of the method at the patient bedside. Thus the method could be used to provide additional, patient specific information on intra- and inter-beat variation in heart function.
本文的目的是建立一种微创方法，逐搏推导左心室时变弹性（TVE）曲线，监测其逐搏演变可为改善诊断和治疗提供重要的新数据和见解。所开发的方法利用临床上可获得的主动脉压力、心率和基线收缩末期容积（通过超声心动图）来确定左心室压力、容积和死腔容积的输出，从而得到TVE曲线。这种方法避免了直接假设TVE曲线的形状，能够更有效地捕捉患者内和患者间的变异性。
所得的TVE曲线通过与动物模型中实验测量的左心室压力和容积推导得到的TVE曲线进行实验验证，该数据集涵盖了5头皮特兰猪的46318次心跳。这种模拟的TVE曲线能够有效地逼近测量得到的TVE曲线，总体中位绝对误差为11.4%，总体中位符号误差为-2.5%。
使用临床上可获得的输入意味着该方法有可能在患者床边实时实施。因此，该方法可用于提供有关心功能患者内和逐搏变化的额外的、针对患者的信息。
