A Comparison of Digital Algorithms Used in Computing the Derivative of Left Ventricular Pressure

Marble, A. E.; Intyre, C. Mark Mc; Hastings-James, R.; Hor, Chou W.

doi:10.1109/tbme.1981.324739

Cited by 89 publications

(25 citation statements)

References 2 publications

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“…Using a sliding second order polynomial fit (22), derivatives of the pressure and volume changes were calculated and appropriately divided point by point to yield the individual relative wall compliances and transfer functions. All compliance and transfer function data were reported at a "driving" ventricular pressure of 5.5 mm Hg in the preterm and newborn infants to describe diastolic ventricular interaction (23,24).…”

Section: Methodsmentioning

confidence: 99%

Developmental Changes in Diastolic Ventricular Interaction

et al. 1988

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ABSTRACT. Developmental changes in the myocardial diastolic ventricular interaction of hearts excised from 12 preterm (126 2 0.8 S E days gestation; term = 147 days) and eight newborn (2.5 2 0.2 SE days postnatal age) lambs were evaluated in vitro. The excised hearts were immersed in a cold cardioplegic solution during which time compliant balloon catheters were inserted into the right and left ventricles through the pulmonary artery and aorta, respectively. The catheters were alternately connected to an infusion pump and appropriate transducers in order to obtain simultaneous biventricular pressure and volume measurements as the volume of each ventricle was varied. Computerized analysis of the pressure and volume recordings was used to determine right and left ventricular free wall compliance, ventricular septal compliance, and pressure and volume transfer functions. Ventricular septal compliance was significantly less than the free wall compliances within both groups. Ventricular septal compliance ( p < 0.05) and transfer functions ( p < 0.05) in the preterm were significantly lower than in the newborn. No significant differences in ventricular free wall compliances were found between or within age groups. These findings demonstrate an increase in ventricular coupling and functional interaction with development, potentially attributable to an increase in septal compliance with development. (Pediatr Res 23: 466-469,1988) Abbreviation HW, heart weight The right and left myocardial ventricles are in direct anatomical apposition and share a common deformable wall, the interventricular septum. Because of this anatomical relationship it is possible for pressure-volume changes in one ventricle to effect pressure-volume changes in the contralateral ventricle. This phenomenon of transferring pressure and/or volume changes from one ventricle to the adjacent ventricle, directly through the myocardium, independent of neural, circulatory, or humoral effects is termed ventricular interaction (1-3). Ventricular interaction occurs during both diastole and systole.Ventricular interaction in the adult myocardium has been well described by theoretical (4, 5) and experimental models (5-7). Other studies have identified transeptal pressure gradients (8, 9) The current literature offers limited data with respect to ventricular interaction in the developing heart. The first objective herein was to compare developmental changes in myocardial compliance and diastolic ventricular interdependence in preterm and newborn lamb hearts. Developmental changes in ventricular interaction were also correlated with maturational changes in wall compliances. Finally, based on the data presented herein as well as force balance considerations across the interventricular septum and wall compliances, we have attempted to explain alterations in ventricular function that occur during development. METHODSAnimalpreparation. Two experimental groups were examined: the first was comprised of 12 preterm lambs (126 +. 0.8 SE days gestation; term = 147 days,...

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Section: Methodsmentioning

confidence: 99%

Developmental Changes in Diastolic Ventricular Interaction

et al. 1988

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“…dP/dt was calculated by computer from LV pressure with a smooth three-point Lagrange derivative, the preferable method for 12-bit digitized data. 24 …”

Section: Data Acquisition and Analysismentioning

confidence: 99%

Sensitivity of left ventricular end-systolic pressure-volume relation to type of loading intervention in dogs.

Baan

Velde

1988

Circulation Research

124

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The influence of different types of loading intervention on the resulting end-systolic pressure-volume relation (ESPVR) of the left ventricle in situ was investigated in anesthetized open-chest dogs. Left ventricular volume was measured by conductance catheter and pressure was measured by tip-micromanometer. Two loading interventions were applied: a pressure intervention (INp) by gradually occluding the descending aorta and a volume intervention (INv) by rapidly infusing 180 ml blood into the vena cava. The pressure-volume loops during an intervention always showed a linear ESPVR, the slope of which, Ees, was calculated. Possible method-related artifacts were assessed and could be excluded. Results from 16 dogs show that Ees(INp) was always larger (1.37 ±0.45 kPa/ml) than Ees(INv) (0.73 ± 0.32 kPa/ml) (p<0.001). This difference was enhanced by /3-blockade through metoprolol. The same phenomenon was found for the slope (SdPV) of the relation between d P / d t^ and end-diastolic volume: SdPV(INp) = 45.17±22.63 kPa/ml/sec and SdPV(INv) = 20.55±11.13 kPa/ml/ sec. In seven dogs, a right heart bypass was performed to study the influence of stroke volume on the ESPVR by applying a pressure intervention under three conditions: with constant end-diastolic volume (decreasing stroke volume), Ees = 2.27 ±0.79 kPa/ml; with constant stroke volume, Ees = 1.59 ±0.51 kPa/ml; and with increasing stroke volume (and increasing end-diastolic volume), Ees = 1.36 ± 0.49 kPa/ml. Analysis of variance revealed a statistically significant relation between Ees and stroke volume (/X0.01). From the right heart bypass experiments, we conclude that shorteningrelated deactivation plays a role in the observed behavior of the ESPVR. However, the results from the series with intact circulation indicate that aortic occlusion has an additional effect on the slope of the ESPVR, leading to increased myocardial inotropism, perhaps mediated through a peripheral stimulus in response to decreased perfusion. (Circulation Research 1988;62:1247-1258 D iastolic cardiac muscle length, reflected by I end-diastolic ventricular volume (EDV), has a strong influence on the mechanical function of the ventricle, whether expressed as stroke volume (SV), systolic pressure, or external work. This formulation, known as Starling's law of the heart, 1 is considered rather inadequate nowadays because other variables such as aortic pressure and heart rate have an even more profound influence on cardiac mechanical performance. A reduction in total vascular resistance, for example, brought on by vasodilator therapy, reduces aortic pressure and increases SV primarily by a reduction in end-systolic volume. Rather than using ventricular function curves or graphs representing the dependence of variables such as SV or work and ejection fraction on preload (EDV) or afterload [aortic pressure, systolic left ventricular (LV) pressure], it is useful to describe ventricular performance in the pressurevolume (PV) plane. The first to propose such methods to describe the work performed by ...

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“…This method of volume calculation gives consistent measures of LV volume despite changes in loading conditions and inotropic state (3). Calculated rate of increase of LV pressure over time (dP/dt) was derived from LV pressure by the five-point Lagrangian fit (11). The rate of LV relaxation was analyzed by determining the time constant of the isovolumic fall of LV pressure (tau) from the peak ϪdP/dt to 5 mmHg above LV enddiastolic pressure (EDP).…”

Section: Methodsmentioning

confidence: 99%

Actions of a novel synthetic natriuretic peptide on hemodynamics and ventricular function in the dog

Lainchbury

Lisý

Burnett

et al. 2002

American Journal of Physiology-Regulatory, Integrative and Comp

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is a recently discovered peptide with structural similarity to known natriuretic peptides. DNP has been shown to possess potent renal actions. Our objectives were to define the acute hemodynamic actions of DNP in normal anesthetized dogs and the acute effects of DNP on left ventricular (LV) function in conscious chronically instrumented dogs. In anesthetized dogs, DNP, but not placebo, decreased mean arterial pressure (141 Ϯ 6 to 109 Ϯ 7 mmHg, P Ͻ 0.05) and pulmonary capillary wedge pressure (5.8 Ϯ 0.3 to 3.4 Ϯ 0.2 mmHg, P Ͻ 0.05). Cardiac output decreased and systemic vascular resistance increased with DNP and placebo. DNP-like immunoreactivity and guanosine 3Ј,5Ј-cyclic monophosphate concentration increased without changes in other natriuretic peptides. In conscious dogs, DNP decreased LV end-systolic pressure (120 Ϯ 7 to 102 Ϯ 6 mmHg, P Ͻ 0.05) and volume (32 Ϯ 6 to 28 Ϯ 6 ml, P Ͻ 0.05) and LV end-diastolic volume (38 Ϯ 5 to 31 Ϯ 4 ml, P Ͻ 0.05) but not arterial elastance. LV end-systolic elastance increased (6.1 Ϯ 0.7 to 7.4 Ϯ 0.6 mmHg/ml, P Ͻ 0.05), and Tau decreased (31 Ϯ 2 to 27 Ϯ 1 ms, P Ͻ 0.05). The effects on hemodynamics, LV function, and second messenger generation suggest synthetic DNP may have a role as a cardiac unloading and lusitropic peptide. natriuretic peptides; systolic function; diastolic function DENDROASPIS NATRIURETIC PEPTIDE (DNP) is a recently discovered 38-amino acid peptide, isolated from the Dendroaspis augusticeps snake, with structural similarity to atrial, brain, and C-type natriuretic peptide (ANP, BNP, and CNP) (4, 18). DNP-like immunoreactivity has been reported in human atria and plasma and is increased in the plasma of patients with congestive heart failure (17). Recently, DNP-like immunoreactivity has been reported in canine plasma and myocardium, and synthetic DNP has been shown to be markedly natriuretic in dogs (10). Indeed, the potent renal actions of synthetic DNP suggest its potential use in the treatment of cardiovascular disease states such as congestive heart failure.The natriuretic peptides have natriuretic and vasodilating properties that are mediated by the second messenger guanosine 3Ј,5Ј-cyclic monophosphate (cGMP). Studies with synthetic DNP to date indicate that it, too, produces natriuresis, causes relaxation in rodent aorta and rodent and canine coronary arteries, and augments formation of cGMP from aortic endothelial cells (4,18). Most recently, we demonstrated that the natriuretic peptides possess direct inotropic and lusitropic myocardial actions in the dog (9, 24). However, the effects of synthetic DNP on systemic hemodynamics and left ventricular (LV) function in vivo are poorly defined.The aim of the current study was to observe the acute in vivo effects of synthetic DNP on systemic hemodynamics and LV function in normal dogs. We hypothesized that exogenously infused synthetic DNP would result in reductions in preload and afterload, together with improvements in ventricular systolic and diastolic function in normal dogs. METHODSExperiments were perfo...

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A Comparison of Digital Algorithms Used in Computing the Derivative of Left Ventricular Pressure

Cited by 89 publications

References 2 publications

Developmental Changes in Diastolic Ventricular Interaction

Developmental Changes in Diastolic Ventricular Interaction

Sensitivity of left ventricular end-systolic pressure-volume relation to type of loading intervention in dogs.

Actions of a novel synthetic natriuretic peptide on hemodynamics and ventricular function in the dog

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