Evaluation of Impedance based indices of cardiac contractility in dogs

Peng, Zhiyong; Critchley, Lester A. H.; Fok, Benny S. P.; James, Anthony E.

doi:10.1023/b:jocm.0000032720.02801.e6

Cited by 10 publications

(22 citation statements)

References 17 publications

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“…PEP, measured in milliseconds (ms), was computed as the time interval between maximum depolarization of left ventricular (R peak on EA ECG beat) and opening of the aortic valve (B point on EA ICG beat) (Seery et al, 2016). HI, measured as ( dZ/dt ) max /RC in ohm/sec 2 , was computed as ratio of maximum amplitude of ICG representing maximum blood velocity in aorta (amplitude of C point on EA ICG beat), and time interval between R peak and C point on EA ECG and ICG beats respectively (Peng et al, 2004). Figure 1b depicts the measurements of PEP and HI via synchronized ECG and ICG waveforms.…”

Section: Methodsmentioning

confidence: 99%

“…The HI approximates the blood acceleration in the aorta during systole, and is measured in units of ohm/sec 2 (Baker et al, 1983). More recently, HI has been measured as ( dZ / dt ) max /RC (Peng et al, 2004), which has the advantage of the ease in the detection of R peak on the ECG signal.…”

Section: Introductionmentioning

confidence: 99%

“…Laboratory experiments with animals have demonstrated that HI is correlated with the acceleration of blood through the aorta and represents the pumping ability of the heart. Reductions in HI values are 4 to 5 times more sensitive in detecting contractility than other measures like PEP and left ventricular ejection time (Baker et al, 1983; Peng et al, 2004). Low HI values were observed in patients with clinical evidence of heart failure as well (Hubbard et al, 1986).…”

Section: Introductionmentioning

confidence: 99%

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Association between PTSD and Impedance Cardiogram‐based contractility metrics during trauma recall: A controlled twin study

et al. 2022

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Post-traumatic stress disorder (PTSD) is an independent risk factor for incident heart failure, but the underlying cardiac mechanisms remained elusive.Impedance cardiography (ICG), especially when measured during stress, can help understand the underlying psychophysiological pathways linking PTSD with heart failure. We investigated the association between PTSD and ICG-based contractility metrics (pre-ejection period (PEP) and Heather index (HI)) using a controlled twin study design with a laboratory-based traumatic reminder stressor.PTSD status was assessed using structured clinical interviews. We acquired synchronized electrocardiograms and ICG data while playing personalized-trauma scripts. Using linear mixed-effects models, we examined twins as individuals and within PTSD-discordant pairs. We studied 137 male veterans (48 pairs, 41 unpaired singles) from Vietnam War Era with a mean (standard deviation) age of 68.5(2.5) years. HI during trauma stress was lower in the PTSD vs. non-PTSD individuals (7.2 vs. 9.3 [ohm/s 2 ], p = .003). PEP reactivity (trauma minus neutral) was also more negative in PTSD vs. non-PTSD individuals (−7.4 vs. −2.0 [ms], p = .009). The HI and PEP associations with PTSD persisted for adjusted models during trauma and reactivity, respectively. For within-pair analysis of eight PTSD-discordant twin pairs (out of 48 pairs), PTSD was associated with lower HI in neutral, trauma, and reactivity, whereas no association was found between PTSD and PEP. PTSD was associated with reduced HI and PEP, especially with

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Association between PTSD and Impedance Cardiogram‐based contractility metrics during trauma recall: A controlled twin study

et al. 2022

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“…Rather than using the differential of the transthoracic bioimpedance signal (dZ/dt) to derive stroke volume the Aesculon uses the second derivative. A study that used an animal flow probe model to investigate the bioimpedance method showed that the second differential of the bioimpedance waveform, or acceleration index (ACI), was better correlated to equivalent aortic flow probe variables than was cardiac output (n = 16 dogs) [14], providing some rational for the Aesculon's new approach to bioimpedance signal analysis. Wong and colleagues studied 35 children, 11 of whom needed prolonged critical asthma therapy.…”

Section: Evaluation Of Haemodynamic Alterations and Fluid Responsivenessmentioning

confidence: 99%

Year in review in journal of clinical monitoring and computing 2014: cardiovascular and hemodynamic monitoring

Bendjelid

Rex

Scheeren

et al. 2015

J Clin Monit Comput

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“…The electrical impedance cardiography, one of the plethysmography, has been extensively applied to assess cardiac parameters, because of its minimal invasiveness of nature. The stroke volume, cardiac output, diastolic filling, ventricular contractility, and so forth, have been evaluated using this impedance plethysmography in previous literature [1][2][3][4][5]. According to the electrode arrangement and location, there are three most popular electrical impedance technologies applied for non-invasively assessing cardiac pumping function.…”

Section: Introductionmentioning

confidence: 99%

Development of forearm impedance plethysmography for the minimally invasive monitoring of cardiac pumping function

Wang¹,

Hu²,

Kao³

et al. 2011

JBiSE

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It is essential to continuously and non-invasively monitor the cardiac pumping function in clinical setting. Thus, the study aimed to explore a regional impedance phethysmographic method to assess the changes in stroke volume. To do this, we developed a plethysmographic device that was capable of delivering a single-frequency current with constant amplitude and of recording electrical impedance signals of biological tissue. The electrical impedance plethy- smographic waveform form the lower arm was measured with the impedance plethysmographic device, and simultaneously the end-systolic and end- diastolic volumes of the left ventricle were obtained with a two-dimension echocardiographic system in fourteen healthy subjects before and immediately after a thirty-second breath-hold maneuver. For the 14 subjects, a linear correlation coefficient of 0.79 (p < 0.001) was obtained between the changes in peak amplitude of the forearm impedance waveform and the changes in stroke volume before and just after the breath-hold test. In addition, the changes in the mean area under the impedance curve and the change in stroke volume were also correlated linearly (r = 0.71, p < 0.005). In summary, the forearm impedance plethysmography may be employed to evaluate the beat-to-beat alteration in cardiac stroke volume, suggesting its potential for long-term monitoring cardiac pumping performance

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Evaluation of Impedance based indices of cardiac contractility in dogs

Abstract: ACI and the Heather index were the most reliable impedance derived indices of cardiac contractility.

Cited by 10 publications

References 17 publications

Association between PTSD and Impedance Cardiogram‐based contractility metrics during trauma recall: A controlled twin study

Association between PTSD and Impedance Cardiogram‐based contractility metrics during trauma recall: A controlled twin study

Year in review in journal of clinical monitoring and computing 2014: cardiovascular and hemodynamic monitoring

Development of forearm impedance plethysmography for the minimally invasive monitoring of cardiac pumping function

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