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Ellis-Reis RE, Visser LC, Hsue W, Sharpe AN, Kaplan JL. Echocardiographic evaluation of regurgitant fraction in dogs with subclinical myxomatous mitral valve disease: Method comparison, effects of pimobendan, and reproducibility. J Vet Cardiol 2023; 45:27-40. [PMID: 36630740 DOI: 10.1016/j.jvc.2022.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 12/08/2022] [Accepted: 12/11/2022] [Indexed: 12/15/2022]
Abstract
INTRODUCTION/OBJECTIVES To evaluate regurgitant fraction (RF) using Simpson's method of discs to estimate total stroke volume (RFSMOD_TSV) and using Motion-mode to estimate total stroke volume (RFM-modeTSV) in dogs with subclinical myxomatous mitral valve disease (MMVD). We also sought to evaluate the effects of pimobendan on RF, and to determine the reproducibility of RFSMOD_TSV and RFM-modeTSV. ANIMALS, MATERIALS, AND METHODS Echocardiography was performed on 57 dogs with MMVD (30 stage B1 and 27 stage B2). Ten dogs received pimobendan for 7-10 days and had a second echocardiogram. Nine dogs underwent six repeated echocardiographic examinations by two operators on three nonconsecutive days within one week for reproducibility analysis. RESULTS Both RFSMOD_TSV and RFM-modeTSV exhibited a curvilinear relationship with left atrium-to-aortic root ratio. Both RFSMOD_TSV and RFM-modeTSV varied considerably within stage B1 (minimum-maximum: -9.1%-58.2% and -35.7%-66.2%, respectively) and B2 (13.6%-76.2% and 20.1%-85.7%, respectively). Method comparison showed RFSMOD_TSV and RFM-modeTSV were not interchangeable with proportional bias. Pimobendan significantly reduced RFSMOD_TSV (-32.0% ± 23.3%) and RFM-modeTSV (-19.2% ± 10.9%) within the same dog and relative to controls. Good inter-day and between-operator reproducibility was observed for RFSMOD_TSV and RFM-modeTSV based on intraclass correlation coefficients 0.86-0.90 and 0.83-0.90, respectively. Reproducibility coefficients were 19.6%-24.1% and 24.1%-27.0%, respectively. CONCLUSIONS Use of RF using the total stroke volume method to aid the assessment of dogs with subclinical MMVD might be of clinical value. However, further study is warranted. Based on response to pimobendan and reproducibility analysis, RF SMOD_TSV might be a more reliable technique to quantify RF.
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Affiliation(s)
- R E Ellis-Reis
- William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - L C Visser
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis, CA 95616, USA.
| | - W Hsue
- William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - A N Sharpe
- William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - J L Kaplan
- William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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Hsue W, Sharpe AN, Darling SL, Visser LC, Choi E, Stern JA. Aorto-left atrial fistula secondary to infective aortic endocarditis and endarteritis in a cat with valvular aortic stenosis. J Vet Cardiol 2021; 35:101-107. [PMID: 33906113 DOI: 10.1016/j.jvc.2021.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 03/11/2021] [Accepted: 03/16/2021] [Indexed: 11/16/2022]
Abstract
A cat previously diagnosed with valvular aortic stenosis developed acute respiratory distress. A new continuous heart murmur was noted on physical exam. Echocardiographic examination revealed vegetative lesions on the aortic valve and continuously shunting blood flow from the aorta into the left atrium. Despite initial treatment for left-sided congestive heart failure, the cat died suddenly. In addition to confirming aortic valve endocarditis and an acquired aorto-left atrial shunt, pathological examination identified vegetative lesions on the luminal surface of the ascending aorta. Although antemortem aerobic blood culture, 16s bacterial ribosomal DNA PCR, and Bartonella PCR failed to identify causative organisms, Escherichia coli was identified on postmortem tissue culture of the aortic lesion. This represented a unique case of primary valvular aortic stenosis with secondary infective aortic endocarditis, infective aortic endarteritis, and aorto-left atrial fistula in a cat. It highlighted potential adverse outcomes of aortic stenosis that are more commonly recognized in humans and dogs.
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Affiliation(s)
- W Hsue
- William R. Pritchard Veterinary Medical Teaching Hospital, University of California - Davis, One Garrod Drive, Davis, CA 95616, USA.
| | - A N Sharpe
- William R. Pritchard Veterinary Medical Teaching Hospital, University of California - Davis, One Garrod Drive, Davis, CA 95616, USA
| | - S L Darling
- William R. Pritchard Veterinary Medical Teaching Hospital, University of California - Davis, One Garrod Drive, Davis, CA 95616, USA
| | - L C Visser
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California - Davis, One Garrod Drive, Davis, CA 95616, USA
| | - E Choi
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California - Davis, One Garrod Drive, Davis, CA 95616, USA
| | - J A Stern
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California - Davis, One Garrod Drive, Davis, CA 95616, USA
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Gibson EA, Culp WTN, Kent MS, Mayhew PD, Wisner ER, Wells A, Visser LC. Treatment of a heart base tumor and chylothorax with endovascular stent, stereotactic body radiation therapy, and a tyrosine kinase inhibitor in a dog. J Vet Cardiol 2020; 33:61-68. [PMID: 33418169 DOI: 10.1016/j.jvc.2020.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 11/09/2020] [Accepted: 11/16/2020] [Indexed: 11/29/2022]
Abstract
An 8-year-old 28-kg male castrated rough collie was evaluated for persistent chylothorax secondary to right atrial mass. Cardiac ultrasound and computed tomography revealed a right atrial intra- and extraluminal mass with partial obstruction of the cranial vena cava and secondary chylothorax. Vascular stent placement was elected to alleviate cranial vena cava obstruction and secondary chylothorax. An 18 mm × 180 mm self-expanding stent was deployed in the region of the stricture, spanning the cranial vena cava and right atrium. An intrathoracic drainage catheter and subcutaneous port were placed within the right hemithorax, and antiplatelet therapy was initiated. Four weeks later, the dog underwent stereotactic body radiation therapy. Three months following treatment, the dog was diagnosed with supraventricular tachycardia and received antiarrhythmic therapy and antiangiogenic/antiproliferative medication (Palladia™). Subsequent evaluations confirmed the resolution of arrhythmia and pleural effusion. Combined vascular stent placement and stereotactic body radiation therapy for the treatment of a right atrial intraluminal and extraluminal mass leading to cranial vena cava compression and subsequent chylothorax may lead to long-term survival. A good outcome was achieved in this patient due to resolution of pleural effusion, as well as cytoreduction and presumably delayed progression of tumor growth.
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Affiliation(s)
- E A Gibson
- Veterinary Medical Teaching Hospital, University of California-Davis, School of Veterinary Medicine, Davis, CA, 95616, USA
| | - W T N Culp
- Department of Surgical & Radiological Sciences, University of California-Davis, School of Veterinary Medicine, Davis, CA, 95616, USA.
| | - M S Kent
- Department of Surgical & Radiological Sciences, University of California-Davis, School of Veterinary Medicine, Davis, CA, 95616, USA
| | - P D Mayhew
- Department of Surgical & Radiological Sciences, University of California-Davis, School of Veterinary Medicine, Davis, CA, 95616, USA
| | - E R Wisner
- Department of Surgical & Radiological Sciences, University of California-Davis, School of Veterinary Medicine, Davis, CA, 95616, USA
| | - A Wells
- Advanced Veterinary Specialists, 414 E Carrillo St, Santa Barbara, CA, 93101, USA
| | - L C Visser
- Department of Medicine & Epidemiology, University of California-Davis, School of Veterinary Medicine, Davis, CA, 95616, USA
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Brown CS, Johnson LR, Visser LC, Chan JC, Pollard RE. Comparison of fluoroscopic cardiovascular measurements from healthy dogs obtained at end-diastole and end-systole. J Vet Cardiol 2020; 29:1-10. [PMID: 32348932 DOI: 10.1016/j.jvc.2020.02.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 02/04/2020] [Accepted: 02/17/2020] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Quantitative measurements are commonly implemented to objectively evaluate heart size in dogs. However, recent studies suggest that the phase of cardiac cycle can impact vertebral heart score, thereby potentially influencing clinical management. This study used fluoroscopy to assess the impact of the cardiac cycle on quantitative cardiovascular measurements in healthy dogs of various breeds. ANIMALS, MATERIALS, AND METHODS This was a prospective study. Multiple cardiac and respiratory cycles were recorded fluoroscopically. Peak inspiratory end-systole and end-diastole frames were captured from 49 dogs in right lateral recumbency. Vertebral heart score (VHS), cardiothoracic ratio (CTR), vertebral left atrial size (VLAS), and caudal vena cava diameter ratio (CVCDR) measurements were performed. Mean cardiac measurements were compared between cardiac cycle phases, and the impact of body condition score (BCS), weight, thoracic conformation, sex, and age was evaluated. RESULTS Cardiac cycle had a significant impact on VHS (mean difference: 0.36 ± 0.14 vertebral units between systole and diastole; p < 0.001) and CTR (mean difference: 2.2 ± 1.2% between systole and diastole; p < 0.001). Cardiac cycle had no significant impact on VLAS or CVCDR. Increasing BCS significantly increased variation between systole and diastole in CTR measurements (p = 0.024). CONCLUSIONS The cardiac cycle has a significant effect on VHS and CTR but does not impact VLAS or CVCDR. These findings should be taken into consideration during clinical use of these measurements, especially if a patient is being monitored for cardiac changes over time via serial radiographs.
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Affiliation(s)
- C S Brown
- William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, CA 95616, USA.
| | - L R Johnson
- William R. Pritchard Veterinary Medical Teaching Hospital, Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA
| | - L C Visser
- William R. Pritchard Veterinary Medical Teaching Hospital, Department of Medicine and Epidemiology, University of California, Davis, CA 95616, USA
| | - J C Chan
- William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis, CA 95616, USA
| | - R E Pollard
- William R. Pritchard Veterinary Medical Teaching Hospital, Department of Surgical and Radiological Sciences, University of California, Davis, CA 95616, USA
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Visser LC, Nishimura S, Oldach MS, Bélanger C, Gunther-Harrington CT, Stern JA, Hsue W. Echocardiographic assessment of right heart size and function in dogs with pulmonary valve stenosis. J Vet Cardiol 2019; 26:19-28. [PMID: 31794914 DOI: 10.1016/j.jvc.2019.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 10/28/2019] [Accepted: 11/04/2019] [Indexed: 10/25/2022]
Abstract
INTRODUCTION/OBJECTIVES We sought to determine the prevalence and clinical significance of right heart remodeling and right ventricular (RV) dysfunction in dogs with pulmonary valve stenosis (PS). We also sought to evaluate repeatability of several measurements of severity of PS, right heart size, and RV function in dogs with PS. ANIMALS, MATERIALS AND METHODS Several indices of right atrial (RA) size and RV size and function were prospectively evaluated in 48 dogs with PS. Regression analysis was used to determine if indices of right heart size and function were independently associated with maximum transpulmonary pressure gradient (max PG) and adverse clinical findings (exercise intolerance, syncope, or right heart failure). Eight dogs underwent a second echocardiogram performed by the same operator to assess repeatability of the echocardiographic indices, which was quantified by coefficient of variation (CV) and repeatability coefficient. RESULTS Increased RA size (81%), increased RV wall thickness (83%), and decreased tricuspid annular plane systolic excursion (TAPSE [81%]) were common. Right atrial size, end-diastolic RV area, and RV wall thickness were independently associated with max PG. Decreased TAPSE was independently associated with adverse clinical findings. All indices except RA area (18.6%) and RV systolic velocity (20.7%) had CVs <15%. Repeatability coefficients are available to help distinguish a true change versus measurement variability during serially obtained exams. CONCLUSIONS Right heart remodeling and RV dysfunction are common in dogs with PS and are associated with echocardiographic and clinical severity. Results support the quantitative assessment of right heart size and function in dogs with PS.
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Affiliation(s)
- L C Visser
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA.
| | - S Nishimura
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
| | - M S Oldach
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
| | - C Bélanger
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
| | - C T Gunther-Harrington
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
| | - J A Stern
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
| | - W Hsue
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, One Shields Ave, Davis, CA, 95616, USA
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Visser LC, Sloan CQ, Stern JA. Echocardiographic Assessment of Right Ventricular Size and Function in Cats With Hypertrophic Cardiomyopathy. J Vet Intern Med 2017; 31:668-677. [PMID: 28295648 PMCID: PMC5435046 DOI: 10.1111/jvim.14688] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 01/09/2017] [Accepted: 02/09/2017] [Indexed: 11/28/2022] Open
Abstract
Background Studies evaluating right ventricular (RV) structural and functional abnormalities in feline hypertrophic cardiomyopathy (HCM) are limited. Hypothesis Right ventricular structural and functional abnormalities are present in cats with HCM and are associated with clinical severity. Animals Eighty‐one client‐owned cats. Methods Retrospective 2‐dimensional (2D) echocardiographic study. Right atrial diameter (RAD), RV free wall thickness (RVFWd), RV internal dimension (RVIDd), RV fractional area change (FAC), and tricuspid annular plane systolic excursion (TAPSE) were measured in control cats (n = 26), cats with subclinical HCM (subclinical HCM; n = 31), and cats with HCM and congestive heart failure (HCM + CHF; n = 24). Results Right heart size (RAD, RVFWd, and RVIDd) and RV function (FAC and TAPSE) significantly (all P < .05) increased and decreased, respectively, in the HCM + CHF group compared with controls. In the subclinical HCM group, only RVFWd was significantly (P < .05) higher than in controls. Compared with reference intervals derived from controls, 29% of cats with HCM had increased RVFWd. Increased left ventricular free wall thickness, increased RVIDd and decreased TAPSE independently correlated with increased left atrial size. Cats with HCM and pleural effusion were significantly more likely to have increased RVFWd and had increased RAD and decreased TAPSE compared with cats without pleural effusion. Conclusions and Clinical Importance Right ventricular remodeling and dysfunction occur in some cats with HCM and may be associated with clinical severity. Our results support involvement of RV in the pathophysiology of HCM in some cats and support echocardiographic assessment of the RV in cats with HCM.
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Affiliation(s)
- L C Visser
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA
| | - C Q Sloan
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA
| | - J A Stern
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA
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Gunther-Harrington CT, Ontiveros ES, Hodge TE, Visser LC, Stern JA. Effects of 0.5% Timolol Maleate Ophthalmic Solution on Heart Rate and Selected Echocardiographic Indices in Apparently Healthy Cats. J Vet Intern Med 2016; 30:733-40. [PMID: 26969017 PMCID: PMC4913573 DOI: 10.1111/jvim.13931] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 01/25/2016] [Accepted: 02/25/2016] [Indexed: 11/28/2022] Open
Abstract
Background Echocardiographic assessment of diastolic function is challenging in cats, partially because of transmitral flow pattern fusion associated with high heart rates. With heart rate (HR) reduction, transmitral flow waveforms separate, allowing identification of diastolic dysfunction. Timolol, an ophthalmic, nonselective beta‐blocker used in glaucoma is safe and transiently decreases HR in clinical trials. Hypothesis Administration of timolol ophthalmic solution decreases HR and facilitates echocardiographic assessment of diastolic function in cats without inducing clinically relevant adverse effects. Animals Twenty‐five apparently healthy cats. Methods Electrocardiograms and echocardiograms including transmitral flow patterns were evaluated before and 20 minutes after ocular administration of 1 drop of timolol 0.5% solution. Twenty cats underwent treatment with timolol, and 5 different cats served as untreated controls to evaluate the effects of acclimation to the hospital environment on HR. Results Acclimation to the hospital had no effect on HR in control cats. After timolol administration, a significant median HR reduction of 25 bpm was observed (P < .0001). Timolol had no effect on E/A ratio in cats without E/A fusion (7/20, P = .44). Of the 13 cats with E and A waves that were fused before timolol application, separation of these waves was identified in 8 cats (62%) after timolol treatment. No bradyarrhythmias were noted after timolol administration, but 2 cats had first‐degree atrioventricular block. Timolol resulted in resolution of dynamic outflow tract obstruction in 6 of 6 cats. Conclusions and clinical importance Ocular administration of timolol safely decreases HR in cats and could facilitate assessment of diastolic function.
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Affiliation(s)
- C T Gunther-Harrington
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA
| | - E S Ontiveros
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA
| | - T E Hodge
- Veterinary Medical Center, University of California, San Diego, CA
| | - L C Visser
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA
| | - J A Stern
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, CA
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Visser LC, Im MK, Johnson LR, Stern JA. Diagnostic Value of Right Pulmonary Artery Distensibility Index in Dogs with Pulmonary Hypertension: Comparison with Doppler Echocardiographic Estimates of Pulmonary Arterial Pressure. J Vet Intern Med 2016; 30:543-52. [PMID: 26893108 PMCID: PMC4913611 DOI: 10.1111/jvim.13911] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 12/01/2015] [Accepted: 01/28/2016] [Indexed: 11/28/2022] Open
Abstract
Background Noninvasive diagnosis of pulmonary hypertension (PH) primarily relies upon Doppler echocardiography of tricuspid regurgitation (TR). However, TR might be absent or difficult to measure. Hypothesis/Objectives To determine the diagnostic value of right pulmonary artery distensibility (RPAD) index for prediction of Doppler‐derived estimates of pulmonary artery (PA) pressure compared to other indices of PH in dogs. Animals Sixty‐nine client‐owned dogs with TR. Methods Prospective observational study. Dogs were allocated to groups according to TR pressure gradient (TRPG): TRPG <36 mmHg (control, n = 22), TRPG 36–50 (n = 16), TRPG 50–75 (n = 14) and TRPG >75 mmHg (n = 17). Right pulmonary artery distensibility index, acceleration time to peak PA flow (AT), AT: ejection time of PA flow (AT:ET) and main PA size: aorta size (MPA:Ao) were calculated in each dog. Results Right pulmonary artery distensibility index demonstrated the strongest correlation (r = −0.90; P < .0001) to TRPG followed by MPA:Ao (r = 0.78; P < .0001), AT (r = −0.69; P < .0001) and AT:ET (r = −0.68; P < .0001). RPAD index possessed the most accurate cutoff (<29.5%; Sensitivity [Sn] 0.84, Specificity [Sp] 0.95) to predict TRPG >50 mmHg compared to AT (<53.9 ms; Sn 0.74, Sp 0.87), AT:ET (<0.30; Sn 0.61, Sp 0.97) and MPA:Ao (>1.04; Sn 0.94, Sp 0.74). All intra‐ and interobserver measurement variabilities exhibited coefficients of variation ≤13%. Conclusions and Clinical Importance Right pulmonary artery distensibility index is an accurate predictor of TRPG and should be particularly useful if TR is absent or difficult to measure.
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Affiliation(s)
- L C Visser
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA
| | - M K Im
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA
| | - L R Johnson
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA
| | - J A Stern
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA
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Visser LC, Carloni R, Klijnstra F, Stramigioli S. A prototype of a novel energy efficient variable stiffness actuator. Annu Int Conf IEEE Eng Med Biol Soc 2010; 2010:3703-6. [PMID: 21096859 DOI: 10.1109/iembs.2010.5627424] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In this work, we present a proof of concept of a novel variable stiffness actuator. The actuator design is based on the conceptual design proposed in earlier work, and is such that the apparent output stiffness of the actuator can be changed independently of the output position and without any energy cost. Experimental results show that the behavior of the prototype is in accordance with the theoretical results of the conceptual design, and thus show that energy efficient variable stiffness actuators can be realized.
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Affiliation(s)
- L C Visser
- Department of Electrical Engineering, Faculty of Electrical Engineering, Mathematics and Computer Science, University of Twente, 7500 AE Enschede, The Netherlands.
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