The “Heather index” in impedance cardiography

Linde, M; Ohnhaus, E. E.; Kirch, Wilhelm

doi:10.1016/0167-5273(88)90248-3

Cited by 4 publications

(2 citation statements)

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“…A modi®ed Heather Index (HI) was calculated as the ratio of (dZ/dt) min , normalized with respect to Z 0 , to the time interval between the ECG R-wave and the occurrence of (dZ/dt) min (Sherwood et al 1990). The HI is considered to re¯ect general myocardial performance, encompassing mechanical factors (preload, afterload) as well as cardiac contractility (Linde et al 1988).…”

Section: Materials and Measurementsmentioning

confidence: 99%

Blood distribution adaptations in paraplegics during posture changes: peripheral and central reflex responses

Theisen

Vanlandewijck

Sturbois

et al. 2000

European Journal of Applied Physiology

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The veno-arteriolar reflex (VAR) in spinal-cord-injured subjects (SCI) has been attributed little interest, although it might contribute substantially to their blood redistribution. This peripheral reflex response, which is based on an axon reflex, consists of a reduction in limb blood flow following an increase in venal transmural pressure. The purpose of the present investigation was to assess the peripheral and central cardiovascular adaptations of paraplegics with high (HP) and low (LP) spinal lesions to subsequent, passive posture changes involving leg dependency and upright sitting, and to compare them to able-bodied (AB) subjects. Lower-limb cutaneous vascular conductance (CVC) was evaluated from skin blood flow measurements (laser Doppler flowmetry) taken from the dorsal foot, and from ankle blood pressure. Cardiac stroke volume, heart rate and myocardial performance were assessed using impedance cardiography and brachial blood pressure. During leg dependency, a significant vasoconstriction was noted in all three groups. The initial decrease in CVC was higher in HP (-76.82%) than in AB (-45.82%), the values for LP (-67.08%) lying in between these two (significant group x time interaction: F = 2.832; P = 0.042). There were no differences for parameters of central hemodynamics. No between-group differences were noted in any parameter tested during upright sitting. CVC remained at a similar low level as compared to leg dependency, stroke volume decreased, heart rate and blood pressure increased, and myocardial performance remained constant. The present results suggest that paraplegics have a peripheral VAR in their paralyzed lower limbs, and that this contributes to their cardiovascular stability.

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Section: Materials and Measurementsmentioning

confidence: 99%

Blood distribution adaptations in paraplegics during posture changes: peripheral and central reflex responses

Theisen

Vanlandewijck

Sturbois

et al. 2000

European Journal of Applied Physiology

View full text Add to dashboard Cite

show abstract

“…Limited bedside echocardiography to evaluate wall motion and ejection fraction, performed by emergency physicians, has been shown to be feasible and to correlate well with definitive testing, but has not found widespread acceptance 9 10. Impedance cardiography has been evaluated as a means to measure cardiac output, thoracic fluid content and systemic vascular resistance non-invasively 11 12. Although large-scale studies on its diagnostic accuracy have yet to be performed, preliminary research suggests it may have an impact on ED physician decision-making and medication administration in dyspnoeic ED patients 13.…”

Section: Discussionmentioning

confidence: 99%