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Inotropic and lusitropic effects of incremental doses of dobutamine in dogs with right ventricular apical pacing‐induced cardiac dysfunction
Author(s) -
Nakata Telma Mary,
Kaji Hideki,
Matsuura Naoya,
Shimizu Miki,
Tanaka Ryou
Publication year - 2019
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/jvp.12752
Subject(s) - lusitropy , dobutamine , inotrope , ventricle , medicine , cardiology , contractility , diastole , heart rate , hemodynamics , cardiac output , anesthesia , blood pressure
Abstract This study aimed to assess the effects of incremental doses of dobutamine on diastolic function in healthy and rapid ventricular apical pacing ( RVAP )‐induced cardiac dysfunction anesthetized dogs. Inotropic and lusitropic effects of dobutamine (2, 4, 8, and 12 μg kg −1 min −1 ) were assessed through left ventricle ( LV ) pressure–volume relation and Doppler echocardiography in six female dogs before and after 8 weeks of RVAP . Peak rate of LV pressure fall (− dP / dt min ) improved with doses >4 μg kg −1 min −1 in healthy (4,490 ± 970 vs. 3,265 ± 471 mmHg/s, p < 0.05) and >8 μg kg −1 min −1 in RVAP dogs (3,385 ± 1,122 vs. 1,864 ± 849 mmHg/s, p < 0.05) while the time constant of relaxation (tau) reduced with doses >4 μg kg −1 min −1 in both groups (healthy: 24.0 ± 3.7 vs. 28.2 ± 4.9 ms; RVAP : 32.6 ± 8.5 vs. 37.5 ± 11.4 ms, p < 0.05) comparing with baseline. Indices of relaxation (− dP / dt min and tau) suggested preserved lusitropic response in contrast with markedly reduced indices of contractility in the RVAP group compared with healthy group at same infusion rates. Doppler echocardiography showed significant reduction of elastic recoil in failing hearts. The results of this study demonstrated maximal positive lusitropic effects of dobutamine at a dose of 8 μg kg −1 min −1 in ventricular pacing‐induced cardiac dysfunction without further impairment of ventricular filling.