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Pichayapaiboon P, Tantisuwat L, Boonpala P, Saengklub N, Boonyarattanasoonthorn T, Khemawoot P, Kijtawornrat A. Pharmacodynamics and Pharmacokinetics of Injectable Pimobendan and Its Metabolite, O-Desmethyl-Pimobendan, in Healthy Dogs. Front Vet Sci 2021; 8:656902. [PMID: 34490386 PMCID: PMC8417876 DOI: 10.3389/fvets.2021.656902] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 07/30/2021] [Indexed: 11/13/2022] Open
Abstract
Objectives: This study was designed to thoroughly evaluate the effects of bolus pimobendan at a dose of 0.15 mg/kg on cardiac functions, hemodynamics, and electrocardiographic parameters together with the pharmacokinetic profile of pimobendan and its active metabolite, o-desmethyl-pimobendan (ODMP), in anesthetized dogs. Methods: Nine beagle dogs were anesthetized and instrumented to obtain left ventricular pressures, aortic pressures, cardiac outputs, right atrial pressures, pulmonary arterial pressures, pulmonary capillary wedge pressures, electrocardiograms. After baseline data were collected, dogs were given a single bolus of pimobendan, and the pharmacodynamic parameters were obtained at 10, 20, 30, 60, and 120 min. Meanwhile, the venous blood was collected at baseline and 2, 5, 10, 20, 30, 60, 120, 180, 360, and 1,440 min after administration for the determination of pharmacokinetic parameters. Results: Compared with baseline measurements, the left ventricular inotropic indices significantly increased in response to intravenous pimobendan, as inferred from the maximum rate of rise in the left ventricular pressure and the contractility index. Conversely, the left ventricular lusitropic parameters significantly decreased, as inferred from the maximum rate of fall in the left ventricular pressure and the left ventricular relaxation time constant. Significant increases were also noted in cardiac output and systolic blood pressure. Decreases were observed in the systemic vascular resistance, pulmonary vascular resistance, left ventricular end-diastolic pressure, pulmonary capillary wedge pressure, right atrial pressure, and pulmonary arterial pressure. The heart rate increased, but the PQ interval decreased. There was no arrhythmia during the observed period (2 h). The mean maximum plasma concentration (in μg/L) for ODMP was 30.0 ± 8.8. Pimobendan exerted large volume of distribution ~9 L/kg. Conclusions: Intravenous pimobendan at the recommended dose for dogs increased cardiac contraction and cardiac output, accelerated cardiac relaxation but decreased both vascular resistances. These mechanisms support the use of injectable pimobendan in acute heart failure.
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Affiliation(s)
- Poonavit Pichayapaiboon
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Lalida Tantisuwat
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Pakit Boonpala
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Nakkawee Saengklub
- Department of Physiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | | | - Phisit Khemawoot
- Faculty of Medicine Ramathibodi Hospital, Chakri Naruebodindra Medical Institute, Mahidol University, Bangkok, Thailand
| | - Anusak Kijtawornrat
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
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Hwang I, Jin Z, Park JW, Kwon OS, Lim B, Hong M, Kim M, Yu HT, Kim TH, Uhm JS, Joung B, Lee MH, Pak HN. Computational Modeling for Antiarrhythmic Drugs for Atrial Fibrillation According to Genotype. Front Physiol 2021; 12:650449. [PMID: 34054570 PMCID: PMC8155488 DOI: 10.3389/fphys.2021.650449] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/22/2021] [Indexed: 01/11/2023] Open
Abstract
Background: The efficacy of antiarrhythmic drugs (AAD) can vary in patients with atrial fibrillation (AF), and the PITX2 gene affects the responsiveness of AADs. We explored the virtual AAD (V-AAD) responses between wild-type and PITX2 +/--deficient AF conditions by realistic in silico AF modeling. Methods: We tested the V-AADs in AF modeling integrated with patients' 3D-computed tomography and 3D-electroanatomical mapping, acquired in 25 patients (68% male, 59.8 ± 9.8 years old, 32.0% paroxysmal type). The ion currents for the PITX2 +/- deficiency and each AAD (amiodarone, sotalol, dronedarone, flecainide, and propafenone) were defined based on previous publications. Results: We compared the wild-type and PITX2 +/- deficiency in terms of the action potential duration (APD90), conduction velocity (CV), maximal slope of restitution (Smax), and wave-dynamic parameters, such as the dominant frequency (DF), phase singularities (PS), and AF termination rates according to the V-AADs. The PITX2 +/--deficient model exhibited a shorter APD90 (p < 0.001), a lower Smax (p < 0.001), mean DF (p = 0.012), PS number (p < 0.001), and a longer AF cycle length (AFCL, p = 0.011). Five V-AADs changed the electrophysiology in a dose-dependent manner. AAD-induced AFCL lengthening (p < 0.001) and reductions in the CV (p = 0.033), peak DF (p < 0.001), and PS number (p < 0.001) were more significant in PITX2 +/--deficient than wild-type AF. PITX2 +/--deficient AF was easier to terminate with class IC AADs than the wild-type AF (p = 0.018). Conclusions: The computational modeling-guided AAD test was feasible for evaluating the efficacy of multiple AADs in patients with AF. AF wave-dynamic and electrophysiological characteristics are different among the PITX2-deficient and the wild-type genotype models.
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Menciotti G, Abbott JA, Aherne M, Lahmers SM, Borgarelli M. Accuracy of echocardiographically estimated pulmonary artery pressure in dogs with myxomatous mitral valve disease. J Vet Cardiol 2021; 35:90-100. [PMID: 33895627 DOI: 10.1016/j.jvc.2021.03.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Echocardiographically identified pulmonary hypertension is an independent predictor of poor outcome in dogs affected by myxomatous valvular degeneration (MMVD). Systolic pulmonary arterial pressure is routinely estimated based on its relationship with the Doppler-determined velocity of tricuspid regurgitation as defined by the simplified Bernoulli equation (sPAP_D). Experimental studies suggest that the method is imperfect, but its accuracy in dogs with MMVD is not known. ANIMALS Twenty dogs affected by MMVD that had cardiac remodeling and measurable tricuspid regurgitation. METHODS A flow-directed thermodilution monitoring catheter was percutaneously placed in the right external jugular vein and advanced to the main pulmonary artery. Pulmonary arterial systolic pressure was recorded (systolic pulmonary arterial pressure obtained by right heart catheterization [sPAP_C]). A second operator contemporaneously acquired tricuspid regurgitant velocity spectra to calculate sPAP_D. Each operator was blinded to the result of the other techniques. RESULTS Technical difficulties prevented the analysis of catheterization data in two dogs. Eighteen measurement pairs were therefore used for comparison of sPAP_C and sPAP_D through correlation and Bland-Altman analysis. A statistically significant bias between sPAP_C and sPAP_D (mean difference = 0.5 mmHg; confidence interval = -6.5 mmHg, +7.5 mmHg) was not detected. The interval of agreement between the techniques was wide (-27.3 mmHg, +28.2 mmHg). A significant linear association between the two techniques was not identified (r = 0.11, p=0.17). CONCLUSION Echocardiographically estimated pulmonary artery pressure poorly agrees with sPAP_C measurement in dogs affected by MMVD and cardiac remodeling with or without previously diagnosed congestive heart failure. In these dogs, sPAP_D could under- or over-estimate sPAP_C by more than 20 mmHg, and therefore caution should be used when interpreting sPAP_D.
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Affiliation(s)
- G Menciotti
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA, 24061, USA.
| | - J A Abbott
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA, 24061, USA
| | - M Aherne
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA, 24061, USA
| | - S M Lahmers
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA, 24061, USA
| | - M Borgarelli
- Department of Small Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA, 24061, USA
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Diagnosis and management of canine atrial fibrillation. Vet J 2020; 265:105549. [PMID: 33129554 DOI: 10.1016/j.tvjl.2020.105549] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 09/21/2020] [Indexed: 11/24/2022]
Abstract
Atrial fibrillation (AF) is the most common non-physiological arrhythmia in dogs and humans. Its high prevalence in both species and the impact it has on survival time and quality of life of affected patients, makes it a very relevant topic for medical research. In dogs, the diagnosis of AF is usually fairly straightforward, but optimal management can be complicated. Rate control is the most commonly used strategy; rhythm control can also be considered in very specific cases. Concurrent congestive heart failure is frequently identified, which represents an extra challenge for the clinicians. This article reviews the current recommendations for the diagnosis and management considerations of AF in dogs. Future perspectives, focusing on new drugs that may prevent development of AF based on recent discoveries, will also be discussed.
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Saengklub N, Limprasutr V, Sawangkoon S, Hamlin RL, Kijtawornrat A. Dronedarone attenuates the duration of atrial fibrillation in a dog model of sustained atrial fibrillation. Exp Anim 2017; 66:251-258. [PMID: 28381818 PMCID: PMC5543246 DOI: 10.1538/expanim.17-0002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Atrial fibrillation (AF) is a supraventricular arrhythmia that leads to a decrease in
cardiac output and impairs cardiac function and quality of life. Dronedarone has an
atrial-selective property and has been used for management of AF in humans, but limited
information is available in dogs. This study was designed to evaluate efficacy of
dronedarone in attenuating the duration of AF in dog model of sustained AF. Six beagle
dogs were anesthetized with isoflurane and instrumented to measure atrial action potential
duration (aAPD) and atrial effective refractory period (AERP). Then AF was induced by
rapid right atrial pacing (20 V, 40 Hz) simultaneously with infusion of phenylephrine (2
µg/kg/min, intravenously) for 20 min. The duration of sustained AF was
recorded, and the animals were allowed to recover. Dronedarone was given at a dose of 20
mg/kg, BID, orally for 7 days. On the last day, the dogs were anesthetized again to record
aAPD and AERP, and AF was induced with the same procedure as described above. The results
showed that after dronedarone administration the aAPD was lengthened significantly from
76.4 ± 4.2 ms to 91.2 ± 3.9 ms (P<0.05) and AERP was prolonged
significantly from 97.5 ± 2.8 ms to 120 ± 4.8 ms (P<0.05). The
duration of sustained AF was also significantly attenuated after receipt of dronedarone
(P<0.05). It can be suggested that oral dronedarone attenuates the
duration of sustained AF in a dog model of AF by extending the AERP more than the aAPD,
causing post-repolarization refractoriness. Hence, dronedarone may be useful for
management of AF in dogs.
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Affiliation(s)
- Nakkawee Saengklub
- Animal Physiology Program, Faculty of Veterinary Science, Chulalongkorn University, 39 Henri Dunant Road, Pathumwan, Bangkok 10330, Thailand
| | - Vudhiporn Limprasutr
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, 39 Henri Dunant Road, Pathumwan, Bangkok 10330, Thailand
| | - Suwanakiet Sawangkoon
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, 39 Henri Dunant Road, Pathumwan, Bangkok 10330, Thailand
| | - Robert L Hamlin
- QTest Labs, Ltd., 6456 Fiesta Drive, Columbus, Ohio 43235, USA
| | - Anusak Kijtawornrat
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, 39 Henri Dunant Road, Pathumwan, Bangkok 10330, Thailand.,Research clusters: research study and testing of drug's effect related to cardiovascular system in laboratory animal, Chulalongkorn University, 39 Henri Dunant Road, Pathumwan, Bangkok 10330, Thailand
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The inflammatory state provokes sexual dimorphism in left ventricular and electrocardiographic effects of chronic cyclosporine in rats. Sci Rep 2017; 7:42457. [PMID: 28211883 PMCID: PMC5304161 DOI: 10.1038/srep42457] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 01/11/2017] [Indexed: 01/22/2023] Open
Abstract
Although cardiotoxicity has been recognized as an adverse effect of cyclosporine A (CSA), no information exists regarding sex specificity of CSA cardiotoxicity. We tested the hypothesis that left ventricular (LV) and electrocardiographic (ECG) effects of CSA and related inflammatory/histopathological derangements are sex related. CSA reduced the LV slope of end-systolic pressure volume relationship and increased isovolumic relaxation constant. These effects were more pronounced in male compared to female rats, suggesting LV systolic and diastolic dysfunction. ECG recordings showed elevated ST segments and increased QTc and T peak trend intervals in CSA-treated male rats, markers of LV ischemia and arrhythmogenesis. In female rats, CSA delayed AV conduction, as reflected by prolonged PR interval. Other sex-related effects for CSA included (i) increased blood cholesterol, and reduced rates of rise and fall in LV pressure and nuclear factor kappa B and angiotensin receptors type 1 expressions in male rats, and (ii) increased LV adiponectin in females. Histopatholgically, CSA caused vascular congestion, blood extravasation, and pyknotic or even absent nuclei in both sexes. In conclusion, rats exhibit sex-independent susceptibility to negative LV and histopathological influences of CSA. These effects become more intensified in male rats, perhaps on account of aggravated ischemic and inflammatory milieus.
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Saengklub N, Youngblood B, Del Rio C, Sawangkoon S, Hamlin RL, Kijtawornrat A. Short-term effects of oral dronedarone administration on cardiac function, blood pressure and electrocardiogram in conscious telemetry dogs. J Vet Med Sci 2016; 78:977-85. [PMID: 26922916 PMCID: PMC4937158 DOI: 10.1292/jvms.15-0481] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dronedarone is a multichannel blocking antiarrhythmic drug that has been used for management of atrial
fibrillation in humans, but the data in veterinary medicine are inadequate. The objective of this study was to
determine the short-term effects of oral dronedarone on cardiac inotropy and lusitropy, blood pressure and
electrocardiogram (ECG) in healthy dogs. A total of 6 beagle dogs were instrumented with telemetry units and
sono-micrometry crystals to obtain left ventricular pressure-volume relationship, mean blood pressure (MBP)
and ECG. Dogs were given orally dronedarone (20 mg/kg, twice per day) for 7 days. All parameters were obtained
hourly at 4–8 hr after the first dose and at 12-, 96- (day 4) and 168-hr (day 7) after dosing. The results
showed that dronedarone had no effect on inotropy and lusitropy, while it significantly lengthened PQ interval
(P<0.001) and lowered MBP (P<0.05). Dronedarone also tended to
reduce cardiac output (P=0.237) and heart rate (P=0.057). These results
suggested that short-term effects of oral dronedarone administration at a dose of 20 mg/kg, twice per day,
produced negative dromotropy with minimal effect on cardiac function in conscious dogs.
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Affiliation(s)
- Nakkawee Saengklub
- Graduate Student in the Program of Animal Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
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