The Ultra Low Frequency Force Ballistocardiograph in Acute Cardiomyopathy
TL;DR: In this study, ultra low frequency force ballistocardiograms were recorded throughout the course of various types of acute cardiomyopathy, suggesting that this type of recording appears to offer a useful means of diagnosing and following the Course of such disease entities.
Abstract: In this study, ultra low frequency force ballistocardiograms were recorded throughout the course of various types of acute cardiomyopathy. Conditions studied included rheumatic carditis, lupus myocarditis, sarcoid carditis, viral myocarditis, acute glomerulonephritis, idiopathic myocarditis, and familial fibrous disease of the myocardium. The instrument used was characterized by an unusually light platform and a very high performance accelerometer. In 14 of the 15 cases studied, tracings were abnormal initially; the recorded force pattern subsequently manifested progressive change which appeared to parallel the clinical course of the disease. Changes included appearance of abnormal forces in early ventricular systole, progressive change in amplitude of acceleration and deceleration forces, appearance of abnormal high frequency components in various portions of the complex, and appearance of abnormal footward forces in late systole.
The alterations thus recorded appear to offer a useful means of diagnosing and following the course of such disease entities. In some cases, this type of recording appears to provide information not available through any other conventional means.
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14 Jan 2019
TL;DR: This paper reviews the recent advances in the field of SCG and focuses on developing proper signal processing algorithms for noise reduction, and SCG signal feature extraction and classification.
Abstract: Cardiovascular disease is a major cause of death worldwide. New diagnostic tools are needed to provide early detection and intervention to reduce mortality and increase both the duration and quality of life for patients with heart disease. Seismocardiography (SCG) is a technique for noninvasive evaluation of cardiac activity. However, the complexity of SCG signals introduced challenges in SCG studies. Renewed interest in investigating the utility of SCG accelerated in recent years and benefited from new advances in low-cost lightweight sensors, and signal processing and machine learning methods. Recent studies demonstrated the potential clinical utility of SCG signals for the detection and monitoring of certain cardiovascular conditions. While some studies focused on investigating the genesis of SCG signals and their clinical applications, others focused on developing proper signal processing algorithms for noise reduction, and SCG signal feature extraction and classification. This paper reviews the recent advances in the field of SCG.
145 citations
Cites background from "The Ultra Low Frequency Force Balli..."
...These signal patterns were also found to correlate with the strength of myocardial contractions [17,18] and contain detectable waveform changes during heart disease resolution [19]....
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TL;DR: Time-frequency distributions were often used to estimate the spectrotemporal signal features and appeared more suited for estimating IF of actual SCG signals, and STFT had lower error than CWT methods for most test signals and PCT had the most consistently accurate IF estimations.
Abstract: Accurate estimation of seismocardiographic (SCG) signal features can help successful signal characterization and classification in health and disease. This may lead to new methods for diagnosing and monitoring heart function. Time-frequency distributions (TFD) were often used to estimate the spectrotemporal signal features. In this study, the performance of different TFDs (e.g., short-time Fourier transform (STFT), polynomial chirplet transform (PCT), and continuous wavelet transform (CWT) with different mother functions) was assessed using simulated signals, and then utilized to analyze actual SCGs. The instantaneous frequency (IF) was determined from TFD and the error in estimating IF was calculated for simulated signals. Results suggested that the lowest IF error depended on the TFD and the test signal. STFT had lower error than CWT methods for most test signals. For a simulated SCG, Morlet CWT more accurately estimated IF than other CWTs, but Morlet did not provide noticeable advantages over STFT or PCT. PCT had the most consistently accurate IF estimations and appeared more suited for estimating IF of actual SCG signals. PCT analysis showed that actual SCGs from eight healthy subjects had multiple spectral peaks at 9.20 ± 0.48, 25.84 ± 0.77, 50.71 ± 1.83 Hz (mean ± SEM). These may prove useful features for SCG characterization and classification.
56 citations
Cites background from "The Ultra Low Frequency Force Balli..."
...These signals were also found to reflect the strength of myocardial contractions [21,22] and have detectable waveform changes with heart disease resolution [23]....
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TL;DR: A novel methodology for processing of a ballistocardiogram (BCG) is proposed in which the respiration signal is utilized to improve the averaging of the BCG signal and ultimately the annotation and interpretation of the signal.
Abstract: In this paper a novel methodology for processing of a ballistocardiogram (BCG) is proposed in which the respiration signal is utilized to improve the averaging of the BCG signal and ultimately the annotation and interpretation of the signal. Previous research works filtered out the respiration signal while the novelty of the current research is that, rather than removing the respiration effect from the signal, we utilize the respiration information to improve the averaging and thus analysis and interpretation of the BCG signal in diagnosis of cardiac malfunctions. This methodology is based on our investigation that BCG cycles corresponding to the inspiration and expiration phases of the respiration cycle are different in morphology. BCG cycles corresponding to the expiration phase of respiration have been proved to be more closely related to each other when compared to cycles corresponding to inspiration, and therefore expiration cycles are better candidates to be selected for the calculation of the averaged BCG signal. The new BCG average calculated based on this methodology is then considered as the representative and a template of the BCG signal for further processing. This template can be considered as the output of a clinical BCG instrument with higher reliability and accuracy compared to the previous processing methods.
55 citations
TL;DR: The present and future potential benefits of using BCG to measure cardiac cycle events and its application to clinical and applied research are reviewed.
Abstract: Ballistocardiography (BCG) is a non-invasive technology that has been used to record ultra-low-frequency vibrations of the heart allowing for the measurement of cardiac cycle events including timing and amplitudes of contraction. Recent developments in BCG have made this technology simple to use, as well as time- and cost-efficient in comparison with other more complicated and invasive techniques used to evaluate cardiac performance. Recent technological advances are considerably greater since the advent of microprocessors and laptop computers. Along with the history of BCG, this paper reviews the present and future potential benefits of using BCG to measure cardiac cycle events and its application to clinical and applied research.
32 citations
Cites background from "The Ultra Low Frequency Force Balli..."
...Through contraction of the myocardial wall, certain forces are generated which produce very powerful acceleration and deceleration forces (Phibbs et al., 1967)....
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...Common sense would indicate that any degeneration of the myocardium would likely result in a change of magnitude and characteristics of the forces generated (Phibbs et al., 1967)....
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...cate that any degeneration of the myocardium would likely result in a change of magnitude and characteristics of the forces generated (Phibbs et al., 1967)....
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TL;DR: It is concluded that prearrest hypoxic perfusion significantly contributes to the dysfunction of NHBD cardiac allografts and Pulmonary allogsrafts may be more amenable to procurement ofNHBDs.
31 citations
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TL;DR: Excerpt Acute disseminated lupus erythematosus is a disease of unknown etiology and of polyphasic symptomatology which quite frequently affects the heart.
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