Comparison of Different Methods for Estimating Cardiac Timings: A Comprehensive Multimodal Echocardiography Investigation

Abstract

Cardiac time intervals are important hemodynamic indices and provide information about left ventricular performance. Phonocardiography (PCG), impedance cardiography (ICG), and recently, seismocardiography (SCG) have been unobtrusive methods of choice for detection of cardiac time intervals and have potentials to be integrated into wearable devices. The main purpose of this study was to investigate the accuracy and precision of beat-to-beat extraction of cardiac timings from the PCG, ICG and SCG recordings in comparison to multimodal echocardiography (Doppler, TDI, and M-mode) as the gold clinical standard. Recordings were obtained from 86 healthy adults and in total 2,120 cardiac cycles were analyzed. For estimation of the pre-ejection period (PEP), 43% of ICG annotations fell in the corresponding echocardiography ranges while this was 86% for SCG. For estimation of the total systolic time (TST), these numbers were 43, 80, and 90% for ICG, PCG, and SCG, respectively. In summary, SCG and PCG signals provided an acceptable accuracy and precision in estimating cardiac timings, as compared to ICG.

Wearable Cardiorespiratory Monitoring Employing a Multimodal Digital Patch Stethoscope: Estimation of ECG, PEP, LVET and Respiration Using a 55 mm Single-Lead ECG and Phonocardiogram

“…In addition, a range of respiratory frequencies and depths, as well as simulated apneas were part of the protocol. For the STI estimation, the reference system used an ECG-ICG approach, which is known to be less accurate than echocardiography [29], and in the presented case had a resolution of only 5 ms. Despite these limitations, the reference data stemmed from a clinically validated and approved medical device and should therefore be adequately reliable.…”

“…Several approaches to assessing STIs are available, including echocardiography, impedance cardiography (ICG), photoplethysmography, seismocardiography (SCG), and PCG. Considering echocardiography as the reference, the PCG approach outperforms other methods when PEP and LVET are to be estimated [28], and PCG and SCG deliver comparable results estimating total systolic time and the electromechanical delay [29]. Therefore, several approaches of estimating STI from ECG and PCG have been reported [30,31].…”

“…Therefore, several approaches of estimating STI from ECG and PCG have been reported [30,31]. Despite the work available on PEP estimation using the PCG, there seem to be diverging opinions about whether or not PCG can be used for PEP estimation in principle [29,32].…”

Gyrocardiography: A Review of the Definition, History, Waveform Description, and Applications

“…Gyrocardiography is defined in [ 22 ] as a local pulses signal, obtained by placing a gyroscope in the place of an accelerometer in seismocardiography [ 8 ]. The works published in 2019 on gyrocariography describe new topics and already known topics, such as the heart beat detection [ 9 ], detection of atrial fibrillation [ 64 , 65 ], hemodynamics analysis [ 42 , 66 , 67 ], pulse transit time measurement [ 68 ] and respiratory and cardiac gating [ 69 ]. The review of the state of seismocardiography by A. Taebi et al in 2019 reveals that the analysis of rotational vibrations may provide complementary information to the SCG signal analysis [ 70 ].…”

AI-Based Estimation of End-Systolic Elastance From Arm-Pressure and Systolic Time Intervals

“…From a wider perspective, the incorporation of STIs values as features to approximate E es has been a promising research direction. Several researchers have demonstrated the ability in acquiring these STIs measurements from more simplified modalities including electrocardiography (ECG), phonocardiography (PCG), or seismocardiography (SCG) (Dehkordi et al, 2019;Chung et al, 2020). Such methods provided unobtrusive detection of cardiac time intervals and offer the potential to be integrated into wearable devices.…”