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administered in a randomized order ( https://www.randomizer.org/ ). Baseline data were collected before dobutamine (DOBU baseline ), esmolol (ESMO baseline ), phenylephrine (PHEN baseline ), and high-dose isoflurane (highISO baseline ). Predetermined

Open access
in American Journal of Veterinary Research

the Graduate School of Veterinary Medicine at Hokkaido University. Study protocol Each dog was administered 1 cardiovascular drug (dobutamine hydrochloride, esmolol hydrochloride, milrinone lactate, or phenylephrine hydrochloride) on an

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in American Journal of Veterinary Research

cephalic vein. 4,5 Similarly, esmolol was infused at a rate of 50 or 100 μg/kg/min for 5 minutes via a cephalic vein. 1 Each dog received each of the 4 drug doses. Five minutes after administration of each dose of dobutamine or esmolol, measurements were

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in American Journal of Veterinary Research

-adrenoreceptor antagonist (esmolol) and ivabradine in healthy cats (controls) and in cats with subclinical HCM under general anesthesia. We hypothesized that ivabradine would have minimal effects on LV and LA function but would significantly blunt positive chronotropic

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in American Journal of Veterinary Research

heart rate control. Five boluses of esmolol hydrochloride f (each at 50 μg/kg [22.7 μg/lb]) were administered IV at 15-minute intervals until a heart rate < 200 bpm was attained. Then an esmolol CRI was initiated at a rate of 10 μg/kg/min (4.5 μg

Full access
in Journal of the American Veterinary Medical Association

; that analysis yielded an estimated power of 0.83 with a sample size of 6 dogs. The study was approved by the Oregon State University Institutional Animal Care and Use Committee. Anesthesia and infusion of esmolol Dogs were anesthetized for

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in American Journal of Veterinary Research

Abstract

Objective—To compare Doppler echocardiographic variables of left ventricular (LV) function with those obtained invasively via cardiac catheterization under a range of hemodynamic conditions.

Animals—7 healthy anesthetized cats (1 to 3 years of age).

Procedure—Cats were anesthetized and instrumented to measure the time constant of isovolumic relaxation (tau []), LV end-diastolic pressure (LVEDP), peak negative and positive rate of change of LV pressure, arterial blood pressure, and cardiac output. Echocardiographic variables of diastolic function (isovolumic relaxation time [IVRT], early LV flow propagation velocity [Vp], transmitral and pulmonary venous flow velocity indices, and LV tissue Doppler imaging indices) were measured simultaneously over a range of hemodynamic states induced by treatments with esmolol, dobutamine, cilobradine, and volume loading. Correlation between invasive and noninvasive measures of LV filling was determined by univariate and multivariate regression analyses.

Results—Significant correlations were found between and IVRT, peak Vp, peak late transmitral flow velocity, and peak systolic pulmonary venous flow velocity. A significant correlation was found between LVEDP and early diastolic transmitral flow velocity (peak E) and the ratio of peak E to peak Vp, but not between LVEDP and peak Vp.

Conclusion and Clinical Relevance—IVRT and Vp can be used as noninvasive indices of LV relaxation; Vp was independent of preload and heart rate in this study. The E:Vp ratio may be useful as an indicator of LV filling pressure. (Am J Vet Res 2003;64:93–103)

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in American Journal of Veterinary Research

Abstract

Objectives—To quantify direction and velocity of blood flow in hepatic veins in dogs under different hemodynamic conditions by use of pulsed-wave Doppler ultrasonography.

Animals—10 healthy dogs.

Procedure—Dogs were anesthetized, and venous flow velocities in the quadrate lobe were measured. Arterial blood pressure, right atrial pressure, pulmonary artery pressure, and cardiac output were measured simultaneously. The timing of each waveform during the cardiac cycle was used to identify velocity profiles. Peak waveform velocities were measured during conditions of light anesthesia with isoflurane (baseline; period 1), cardiovascular depression following administration of highdose isoflurane and esmolol IV (period 2), cardiovascular depression with crystalloid volume expansion (period 3), and high cardiac output induced with dobutamine (period 4). Hemodynamic measurements and maximum waveform velocities were compared among the 4 periods by use of an ANOVA and univariate and multivariate linear regression.

Results—During each study period, 4 distinct, lowvelocity waves were identified. Mean velocities recorded during period 1 were as follows: retrograde atrial contraction a-wave, 7.3 cm/s; antegrade systolic S-wave, 15.0 cm/s; retrograde venous return v-wave, 2.7 cm/s; and antegrade diastolic D-wave, 11.4 cm/s. Mean S:D ratio was 1.27. During periods 3 and 4, Swave velocity increased; D-wave velocity was highest during period 4.

Conclusions and Clinical Relevance—Consistent hepatic venous velocity profiles were observed in healthy dogs under different hemodynamic conditions. These findings provide baseline values that may be useful in evaluating clinical cases, but further study involving healthy, awake dogs and dogs with cardiac and hepatic diseases is required. (Am J Vet Res 2004;65:734–740)

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in American Journal of Veterinary Research

evaluated under 6 conditions as follows: baseline (consisting of a light plane of anesthesia [1% to 3% isoflurane]), infusion of a low dose of esmolol hydrochloride k (50 μg/kg/min) to create a condition of myocardial depression, infusion of a high dose of

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in American Journal of Veterinary Research

of approximately 270 beats/min ( Figure 1 ). The mechanism of the SVT could not be determined because p waves were not visible. Two boluses of esmolol (0.5 mg/kg [0.23 mg/lb]) were administered IV at a 10-minute interval with no effect. Administration

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in Journal of the American Veterinary Medical Association