Device-based impedance measurement is a useful and accurate tool for direct assessment of intrathoracic fluid accumulation in heart failure

Becher, Jan; Kaufmann, Susann G.; Paule, Stefan; Fahn, Bernhard; Skerl, Olaf; Bauer, Wolfgang R.; Ertl, Georg; Maier, Sebastian

doi:10.1093/europace/eup413

Cited by 20 publications

(12 citation statements)

References 30 publications

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“…For accuracy, is de-embedded to be by subtracting the input parasitic resistor and capacitor from measured . Then, substituting and into (12) can yield as (18) Once is determined, substituting and , which represents the de-embedded reflected resistance of obtained in the measurement mode, into (12) yields (19) Further, substituting given by (18) into (19) simplifies to (20) Finally, subtracting parasitic resistance and from obtained yields…”

Section: B Measuring Inductive Coupling Impedancementioning

confidence: 99%

In Situ Measurement of Tissue Impedance Using an Inductive Coupling Interface Circuit

Chiu

Chuang

et al. 2013

IEEE Trans. Biomed. Circuits Syst.

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In this work, a method of an inductive coupling impedance measurement (ICIM) is proposed for measuring the nerve impedance of a dorsal root ganglion (DRG) under PRF stimulation. ICIM provides a contactless interface for measuring the reflected impedance by an impedance analyzer with a low excitation voltage of 7 mV. The paper develops a calibration procedure involving a 50-Ω reference resistor to calibrate the reflected resistance for measuring resistance of the nerve in the test. A de-embedding technique to build the equivalent transformer circuit model for the ICIM circuit is also presented. A batteryless PRF stimulator with ICIM circuit demonstrated good accuracy for the acute measurement of DRG impedance both in situ and in vivo. Besides, an in vivo animal experiment was conducted to show that the effectiveness of pulsed radiofrequency (PRF) stimulation in relieving pain gradually declined as the impedance of the stimulated nerve increased. The experiment also revealed that the excitation voltage for measuring impedance below 25 mV can prevent the excitation of a nonlinear response of DRG.

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Section: B Measuring Inductive Coupling Impedancementioning

confidence: 99%

In Situ Measurement of Tissue Impedance Using an Inductive Coupling Interface Circuit

Chiu

Chuang

et al. 2013

IEEE Trans. Biomed. Circuits Syst.

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“…Besides, very recently, Becher et al [42] have published the results of an animal study in which implant-based impedance showed a strong inverse correlation with changes of directly measured intrathoracic fluid accumulation.…”

Section: Clinical Impact Of Hemodynamic Sensorsmentioning

confidence: 99%

Usefulness of Hemodynamic Sensors for Physiologic Cardiac Pacing in Heart Failure Patients

Occhetta

Bortnik

Marino

2011

Cardiology Research and Practice

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The rate adaptive sensors applied to cardiac pacing should respond as promptly as the normal sinus node with an highly specific and sensitive detection of the need of increasing heart rate. Sensors operating alone may not provide optimal heart responsiveness: central venous pH sensing, variations in the oxygen content of mixed venous blood, QT interval, breathing rate and pulmonary minute ventilation monitored by thoracic impedance variations, activity sensors. Using sensors that have different attributes but that work in a complementary manners offers distinct advantages. However, complicated sensors interactions may occur. Hemodynamic sensors detect changes in the hemodynamic performances of the heart, which partially depends on the autonomic nervous system-induced inotropic regulation of myocardial fibers. Specific hemodynamic sensors have been designed to measure different expression of the cardiac contraction strength: Peak Endocardial Acceleration (PEA), Closed Loop Stimulation (CLS) and TransValvular Impedance (TVI), guided by intraventricular impedance variations. Rate-responsive pacing is just one of the potential applications of hemodynamic sensors in implantable pacemakers. Other issues discussed in the paper include: hemodynamic monitoring for the optimal programmation and follow up of patients with cardiac resynchronization therapy; hemodynamic deterioration impact of tachyarrhythmias; hemodynamic upper rate limit control; monitoring and prevention of vasovagal malignant syncopes.

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“…Currently, the techniques for tracking decompensation or general fluid accumulation in HF patients includes daily measures of weight or other more complicated measures such as chest X-ray or CT scans of the lungs, however, it is expensive and/or the diagnostic sensitivity of these techniques is not high (Mahdyoon et al, 1989; Becher et al, 2010; Gupta et al, 2012). In addition, B-type natriuretic peptide (BNP) level, which often increases when HF symptoms are exacerbated, is still in question (Lewin et al, 2005; Becher et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…In addition, B-type natriuretic peptide (BNP) level, which often increases when HF symptoms are exacerbated, is still in question (Lewin et al, 2005; Becher et al, 2010). As fluid accumulation is one of the major predictors of decompensative events associated with HF, it is very important to develop more sensitive and cost-effective techniques.…”

Section: Introductionmentioning

confidence: 99%

“…Impedance, the measure of resistance to the flow of current, has been considered a novel technique for early detection of fluid retention and decompensation (Yu et al, 2005; Andriulli 2007; Yupenburg et al, 2007; Wang, 2007; Becher et al, 2010). Recently Medtronic Inc. (Minneapolis, MN) released the Optivol ™ software, as a unique way of providing preemptive data on disease status by measuring intrathoracic impedance changes from their implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy device (CRT-D).…”

Section: Introductionmentioning

confidence: 99%

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Influence of lung volume, fluid and capillary recruitment during positional changes and exercise on thoracic impedance in heart failure

Kim

Fuglestad

Richert

et al. 2014

Respiratory Physiology & Neurobiology

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It is unclear how dynamic changes in pulmonary-capillary blood volume (Vc), alveolar lung volume (derived from end-inspiratory lung volume, EILV) and interstitial fluid (ratio of alveolar capillary membrane conductance and pulmonary capillary blood volume, Dm/Vc) influence lung impedance (ZT). The purpose of this study was to investigate if positional change and exercise result in increased EILV, Vc and/or lung interstitial fluid, and if ZT tracks these variables. Methods 12 heart failure (HF) patients underwent measurements (ZT, EILV, Vc/Dm) at rest in the upright and supine positions, during exercise and into recovery. Inspiratory capacity was obtained to provide consistent measures of EILV while assessing ZT. Results ZT increased with lung volume during slow vital capacity maneuvers (p<0.05). Positional change (upright→supine) resulted in an increased ZT (p<0.01), while Vc increased and EILV and Dm/Vc decreased (p<0.05). Moreover, during exercise Vc and EILV increased and Dm/Vc decreased (p<0.05), whereas, ZT did not change significantly (p>0.05). Conclusion Impedance appears sensitive to changes in lung volume and body position which appear to generally overwhelm small acute changes in lung fluid when assed dynamically at rest or during exercise.

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Device-based impedance measurement is a useful and accurate tool for direct assessment of intrathoracic fluid accumulation in heart failure

Abstract: Changes of Z show a strong inverse correlation with changes of directly measured EVLWI. This allows the application of Z as a measure of intrathoracic fluid status and has the potential to optimize patient care, especially in the context of evolving telemedicine concepts.

Cited by 20 publications

References 30 publications

In Situ Measurement of Tissue Impedance Using an Inductive Coupling Interface Circuit

In Situ Measurement of Tissue Impedance Using an Inductive Coupling Interface Circuit

Usefulness of Hemodynamic Sensors for Physiologic Cardiac Pacing in Heart Failure Patients

Influence of lung volume, fluid and capillary recruitment during positional changes and exercise on thoracic impedance in heart failure

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