Evaluation of Systolic Performance by Automated Impedance Cardiography

Scherhag, Armin; Stastny, J.; Pfleger, Stefan; Voelker, Wolfram; Heene, D. L.

doi:10.1111/j.1749-6632.1999.tb09464.x

Cited by 4 publications

(3 citation statements)

References 20 publications

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“…Both processes, however, can impact interoception in opposite ways if affected by alpha2-adrenergic blockade. On the one hand, peripheral sympathetic activation increases cardiac contractility (Scherhag, Stastny, Pfleger, Voelker, & Heene, 1999), which increases IAcc (Eichler & Katkin, 1994; Herbert et al, 2010; Moor et al, 2005; Schandry, Bestler, & Montoya, 1993). On the other hand, alpha2-antagonists facilitate alertness, but reduce capacity for focused and selective attention (Clark, Geffen, & Geffen, 1986, 1987; Hermans et al, 2011).…”

Section: Discussionmentioning

confidence: 99%

Noradrenergic activation induced by yohimbine decreases interoceptive accuracy in healthy individuals with childhood adversity

et al. 2021

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Acute stress affects interoception, but it remains unclear if this is due to activation of the sympatho-adreno-medullary (SAM) or hypothalamic–pituitary–adrenocortical axis. This study aimed to investigate the effect of SAM axis activation on interoceptive accuracy (IAcc). Central alpha2-adrenergic receptors represent a negative feedback mechanism of the SAM axis. Major depressive disorder and adverse childhood experiences (ACE) are associated with alterations in the biological stress systems, including central alpha2-adrenergic receptors. Here, healthy individuals with and without ACE as well as depressive patients with and without ACE (n = 114; all without antidepressant medication) were tested after yohimbine (alpha2-adrenergic antagonist) and placebo. We assessed IAcc and sensibility in a heartbeat counting task. Increases in systolic and diastolic blood pressure after yohimbine confirmed successful SAM axis activation. IAcc decreased after yohimbine only in the healthy group with ACE, but remained unchanged in all other groups (Group × Drug interaction). This effect may be due to selective upregulation of alpha2-adrenergic receptors after childhood trauma, which reduces capacity for attention focus on heartbeats. The sympathetic neural pathway including alpha2-adrenergic circuitries may be essential for mediating interoceptive signal transmission. Suppressed processing of physical sensations in stressful situations may represent an adaptive response in healthy individuals who experienced ACE.

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Section: Discussionmentioning

confidence: 99%

Noradrenergic activation induced by yohimbine decreases interoceptive accuracy in healthy individuals with childhood adversity

et al. 2021

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“…Possible artifacts were eliminated using signal‐averaging algorithms to avoid influences on cardiac output measurements. This impedance cardiography system has been shown to produce valid measures of cardiodynamic processes (Scherhag et al, 1997, 1999).…”

Section: Methodsmentioning

confidence: 99%

“…Exact positioning of the electrodes was maintained for the entire study to avoid effects on DZ and dZ/dt max (Sherwood et al, 1990). Correct identification of points B (opening of the aortic valve), P (maximum systolic flow), and X (closure of the aortic valve) on the ICG curves were automatically confirmed by marker channels (e.g., Scherhag et al, 1997;Scherhag, Stastny, Pfleger, Voelker, & Heene, 1999). Possible artifacts were eliminated using signal-averaging algorithms to avoid influences on cardiac output measurements.…”

Section: Assessment Of Respiration Heart Rate and Power Spectral Anamentioning

confidence: 99%

Cardiac awareness and autonomic cardiac reactivity during emotional picture viewing and mental stress

et al. 2010

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This study investigated the relationship between autonomic cardiovascular reactivity and cardiac awareness during the following conditions: baseline, emotional picture viewing, mental stress, and heartbeat tracking. Cardiac parameters were examined by using power spectrum analysis of heart rate variability and impedance cardiography. According to their performance in a heartbeat tracking task, 38 participants were classified as good (n=19) or poor (n=19) heartbeat perceivers. Neither group differed during baseline and heartbeat tracking, but good compared to poor heartbeat perceivers demonstrated greater sympathetic reactivity during mental stress and more vagal reactivity and subjective arousal during emotional picture viewing. The results suggest that cardiac awareness is related to greater responsivity of the autonomic nervous system during situations evoking autonomic reactivity.

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Multi‐site‐frequency electromechanocardiography for the prediction of ejection fraction and stroke volume in heart failure

Skrabal

Mayer

Hopfgartner

et al. 2005

European J of Heart Fail

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Background: Methods for stroke volume (SV) and ejection fraction (EF) measurements require the presence of qualified physicians and are not suited for continuous monitoring. Aim: To develop an automated non-invasive method for the measurement and continuous monitoring of SV and EF. Methods: We have designed a method for the measurement of EF and SV using multiple-site-impedance (z0) measurements, applying multiple frequencies of 5, 40 and 200 kHz whereby various segments of the human body, including volume changes within these segments, could be defined electrically. The obtained variables were used to train neuronal nets and related by multiple regression analyses to cardiac output (CO) as measured by a partial rebreathing Fick method (CO r-fick ) or EF as measured by echocardiography (EF echo ), respectively. A total of 129 subjects (48 with normal heart function and 81 with CHF, NYHA I-IV) were investigated. Results: The multiply derived values of z0 and of change of impedance (dz/dt) were shown, by multiple regression analysis, to be significantly related to CO r-fick and to EF echo , (total r=0.77, n=35, pb0.001, and r=0.81, n=47, pb0.001, respectively.). By training a neuronal net with the electrical data of 67 (out of 94) subjects, EF echo could be predicted in the remaining 27 subjects which were unknown to the neuronal net with a combined r=0.71 ( pb0.001,n=27). In contrast, conventional impedance cardiography (ICG) was unable to predict either CO r-fick or EF echo . Conclusion:The new method, which we call multi-site-frequency electromechanocardiography (msf-ELMC) appears promising for the automated electrical measurement of the mechanical heart action in patients with normal and reduced cardiac function.

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Evaluation of Systolic Performance by Automated Impedance Cardiography

Cited by 4 publications

References 20 publications

Noradrenergic activation induced by yohimbine decreases interoceptive accuracy in healthy individuals with childhood adversity

Noradrenergic activation induced by yohimbine decreases interoceptive accuracy in healthy individuals with childhood adversity

Cardiac awareness and autonomic cardiac reactivity during emotional picture viewing and mental stress

Multi‐site‐frequency electromechanocardiography for the prediction of ejection fraction and stroke volume in heart failure

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