Ambulance Research Institute, Ambulance Service of New South Wales, Rozelle, Sydney, NSW 2039, Australia.
Physiol Meas. 2011 Aug;32(8):1181-92. doi: 10.1088/0967-3334/32/8/012. Epub 2011 Jun 27.
There is a need for robust techniques for early and accurate diagnosis of acute coronary syndromes (ACSs), to avoid inappropriate discharge of patients. This study examined the use of frequency spectrum analysis of heart rate variability (HRV) and photoplethysmogram (PPG) waveform variability for the identification of high-risk ACS patients defined by an elevated cardiac troponin level. The study cohort comprised a convenience sample of adult patients presenting to the emergency department of the Prince of Wales Hospital over a 4 month period complaining of non-traumatic chest pain. Valid electrocardiogram (ECG) and earlobe PPG waveforms together with troponin I test results were obtained from 52 patients at presentation, 4 of which were troponin I positive (Trop 0+). Frequency spectrum analysis was performed on the beat-to-beat HRV and PPG waveform variability (PPGV). The Trop 0+ were found to have significantly higher normalized mid-frequency power (MF(nu)) in HRV (P = 0.017), PPG amplitude variability (P = 0.009) and the cross-spectrum of HRV and PPGV (P = 0.001), which were attributed to reflex sympathetic response to myocardial ischemia. MF(nu) of PPG amplitude had the best overall performance in detecting Trop 0+, with ROC area under the curve of 0.93. The results demonstrate the potential use of ear PPG waveform to identify high-risk heart disease patients, and further highlight the utility of frequency spectrum analysis of PPGV in critical care.
需要稳健的技术来早期准确诊断急性冠状动脉综合征 (ACS)，以避免对患者进行不适当的出院处理。本研究探讨了心率变异性 (HRV) 和光体积描记图 (PPG) 波形变异性的频谱分析在识别因心肌钙蛋白水平升高而定义的高危 ACS 患者中的应用。研究队列由在 4 个月期间因非创伤性胸痛到威尔士亲王医院急诊科就诊的成年患者的方便样本组成。在就诊时从 52 名患者中获得了有效的心电图 (ECG) 和耳垂 PPG 波形以及肌钙蛋白 I 检测结果，其中 4 名患者的肌钙蛋白 I 呈阳性 (Trop 0+)。对逐拍 HRV 和 PPG 波形变异性 (PPGV) 进行了频谱分析。结果发现，Trop 0+患者的 HRV 中归一化中频功率 (MF(nu))（P=0.017）、PPG 幅度变异性（P=0.009）和 HRV 与 PPGV 的互谱（P=0.001）显著较高，这归因于对心肌缺血的反射性交感反应。PPG 幅度的 MF(nu) 在检测 Trop 0+方面表现出最佳的整体性能，ROC 曲线下面积为 0.93。结果表明，耳 PPG 波形有可能用于识别高危心脏病患者，并进一步强调了 PPGV 频谱分析在重症监护中的实用性。
