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Static-charge-sensitive bed ballistocardiography in cardiovascular monitoring
A Lindqvist1, K Pihlajamäki, J Jalonen
1Cardiorespiratory Research Unit, University of Turku, Finland.
Insights
Ballistocardiograms, a non-invasive cardiovascular monitoring tool, reflect autonomic nervous system influence on heart contractility and filling. This technology showed promise in assessing heart function during bypass surgery and exercise.
Area of Science:
- Cardiovascular Physiology
- Autonomic Nervous System Research
- Biomedical Engineering
Background:
- Cardiovascular monitoring is crucial for assessing heart function.
- Ballistocardiography (BCG) offers a non-invasive method for evaluating cardiac activity.
- Understanding autonomic nervous system (ANS) influence on BCG is vital for clinical applications.
Purpose of the Study:
- To evaluate the autonomic influence on BCG signals.
- To assess the clinical utility of BCG in cardiovascular monitoring, particularly during coronary bypass surgery.
- To correlate BCG parameters with ANS modulation and cardiac filling pressures.
Main Methods:
- BCG recordings using a static-charge-sensitive bed in healthy males and patients undergoing coronary bypass surgery.
- Pharmacological interventions (isoprenaline, atropine) and dynamic exercise to modulate ANS activity.
- Analysis of BCG amplitude and temporal waveform characteristics in relation to heart rate and electrocardiogram (ECG).
Main Results:
- BCG amplitude was significantly reduced and distorted during bypass surgery due to impaired cardiac filling, returning to baseline upon restoration of preload.
- Submaximal exercise and isoprenaline increased BCG amplitude threefold and shortened the R-wave to BCG peak interval, indicating sympathetic influence.
- Atropine increased heart rate but did not significantly alter BCG amplitude or temporal patterns, suggesting parasympathetic effects on contractility are less pronounced in BCG.
Conclusions:
- BCG effectively reflects sympathetic and parasympathetic influences on myocardial contractility.
- BCG is sensitive to changes in cardiac filling pressures, demonstrating clinical relevance during procedures like bypass surgery.
- Static-charge-sensitive bed BCG holds potential for non-invasive cardiovascular monitoring and assessment of autonomic function.
Abstract:
We evaluated the autonomic influence on balistocardiograms recorded by a static-charge-sensitive bed for cardiovascular monitoring in nine healthy males (20-44 years) and its clinical use in 11 patients who underwent coronary bypass surgery (51-59 years). The ballistocardiogram displayed a distorted low amplitude from the empty beating heart during bypass surgery, impaired by a reduced effective transmural filling pressure of the heart, and returned to its pre-bypass level when the preload to the heart and its pumping was restored. Submaximal dynamic exercise and isoprenaline caused the heart rate to rise to 90-114 beats min-1, and increased the ballistocardiographic amplitude threefold, while at the same time shortening the interval between the R-wave of the electrocardiogram and the peak of the ballistocardiographic waveform (P < 0.01). In contrast, atropine accelerated the heart rate to 96 beats min-1, but did not significantly change the amplitude or temporal pattern of the ballistocardiogram. Thus, the ballistocardiogram reflects sympathetic and parasympathetic influence on the contractility of the myocardium and the effect of cardiac filling (e.g. during bypass surgery).