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Background Patent ductus arteriosus (PDA) is one of the most common congenital heart defects in dogs. Advanced echocardiographic techniques such as speckle‐tracking echocardiography (STE) have not been extensively used to evaluate cardiac function in affected dogs. Hypothesis Advanced echocardiographic techniques are more sensitive than standard echocardiographic techniques in analyzing systolic function in dogs with PDA. Animals Forty‐four client‐owned dogs: 34 dogs with PDA (preoperative evaluation) and 10 healthy sex‐ and weight‐matched controls. Methods Prospective study. Dogs were recruited over a 2‐year period. Complete echocardiographic evaluation was performed, including conventional (end‐diastolic volumes indexed to body surface area in B and M‐mode [EDVIB/M], end‐systolic volumes indexed to body surface area in B and M‐mode [ESVIB/M], allometric scaling in diastole and systole [AlloD/S], pulmonary flow to systemic flow [Qp/Qs], ejection fraction [EF] and fractional shortening [FS]) and speckle‐tracking echocardiography ([STE]: global longitudinal, radial and circumferential strain [S] and strain rate [SR]). Results Dogs with PDA had significantly different EDVIB/M, ESVIB/M, AlloD/S, Qp/Qs and all STE‐derived parameters (global longitudinal S and SR, global circumferential S and SR, global radial S and SR)compared to healthy dogs. No correlation was found between standard techniques (EDVIB/M, ESVIB/M, AlloD/S, Qp/Qs) and STE‐derived parameters (global longitudinal, circumferential and radial S and SR). Conclusion and Clinical Importance Conventional parameters routinely used to assess systolic function (EF and FS) were not different between the groups; STE‐derived parameters identified subtle changes in cardiac systolic function and contractility between the 2 groups of dogs. Based on these findings, STE may be a more appropriate tool to assess cardiac contractility in dogs with PDA.

Background Patent ductus arteriosus (PDA) is 1 of the most common congenital heart defects in dogs and percutaneous closure is effective in achieving ductal closure; PDA closure is associated with abrupt hemodynamic changes. Hypothesis A marked decrease in standard parameters of systolic function as assessed by M‐ or B‐mode echocardiography after PDA closure was identified in previous studies. Speckle tracking echocardiography can provide further insight into the effect of PDA closure on cardiac mechanics in dogs affected by PDA. Animals Twenty‐five client‐owned dogs with PDA. Methods Prospective study. Dogs were recruited over a 2‐year period. Complete echocardiographic evaluation was performed before and 24 hours after PDA closure, including standard (end‐diastolic volumes indexed to body surface area in B‐ and M‐mode [EDVIB/M], end‐systolic volumes indexed to body surface area in B‐ and M‐mode [ESVIB/M], allometric scaling in diastole [AlloD] and systole [AlloS], pulmonary flow to systemic flow [Qs/Qp], ejection fraction [EF], and fractional shortening [FS]), and advanced speckle‐tracking echocardiography (STE): global longitudinal, radial, circumferential and transverse strain (S), and strain rate (SR). Results Patent ductus arteriosus closure was associated with statistically significant decreases in EDVIM/B and ESVIM/B, AlloD and AlloS, SI, EF, and FS. A statistically significant decrease in the absolute values of radial, transverse, and circumferential S and SR was observed, whereas longitudinal S and SR did not change significantly. Conclusion and Clinical Importance Patent ductus arteriosus closure by percutaneous approach is associated with marked decreases of conventional echocardiographic parameters as a result of the changes in loading conditions, but no evidence of systolic dysfunction was identified by means of STE, as none of the S and SR values were below reference ranges. In the short term, contractility is enhanced in the long axis (long S/SR values were not statistically different before and after closure) and decreases to normal values in short axis (circumferential, radial, and transversal S/SR decreased to normal reference range).

Background: Artificial intelligence (AI) could improve accuracy and reproducibility of echocardiographic measurements in dogs., Hypothesis: A neural network can be trained to measure echocardiographic left ventricular (LV) linear dimensions in dogs., Animals: Training dataset: 1398 frames from 461 canine echocardiograms from a single specialist center., Validation: 50 additional echocardiograms from the same center., Methods: Training dataset: a right parasternal 4-chamber long axis frame from each study, labeled by 1 of 18 echocardiographers, marking anterior and posterior points of the septum and free wall., Validation Dataset: End-diastolic and end-systolic frames from 50 studies, annotated twice (blindly) by 13 experts, producing 26 measurements of each site from each frame. The neural network also made these measurements. We quantified its accuracy as the deviation from the expert consensus, using the individual-expert deviation from consensus as context for acceptable variation. The deviation of the AI measurement away from the expert consensus was assessed on each individual frame and compared with the root-mean-square-variation of the individual expert opinions away from that consensus., Results: For the septum in end-diastole, individual expert opinions deviated by 0.12 cm from the consensus, while the AI deviated by 0.11 cm (P = .61). For LVD, the corresponding values were 0.20 cm for experts and 0.13 cm for AI (P = .65); for the free wall, experts 0.20 cm, AI 0.13 cm (P < .01). In end-systole, there were no differences between individual expert and AI performances., Conclusions and Clinical Importance: An artificial intelligence network can be trained to adequately measure linear LV dimensions, with performance indistinguishable from that of experts., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Impairment of left ventricular (LV) longitudinal function is an early marker of systolic dysfunction in hypertrophic cardiomyopathy (HCM). Aortic annular plane systolic excursion (AAPSE) is a measure of LV longitudinal function in people that has not been evaluated in cats., Hypothesis: Aortic annular plane systolic excursion is lower in cats with HCM compared to control cats, and cats in stage C have the lowest AAPSE., Animals: One hundred seventy-five cats: 60 normal, 61 HCM stage B and 54 HCM stage C cats., Materials: Multicenter retrospective case-control study. Electronic medical records from 4 referral hospitals were reviewed for cats diagnosed with HCM and normal cats. HCM was defined as LV wall thickness ≥6 mm and normal cats ≤5 mm. M-mode bisecting the aorta in right parasternal short-axis view was used to measure AAPSE., Results: Aortic annular plane systolic excursion was lower in HCM cats compared to normal cats (3.9 ± 0.9 mm versus 4.6 ± 0.9 mm, P < .001) and was lowest in HCM stage C (2.4 ± 0.6 mm, P < .001). An AAPSE <2.9 mm gave a sensitivity of 83% (95% CI 71%-91%) and specificity of 92% (95% CI 82%-97%) to differentiate HCM stage C from stage B. AAPSE correlated with mitral annular plane systolic excursion (r = .6 [.4-.7], P < .001), and atrial fractional shortening (r = .6 [.5-.7], P < .001), but showed no correlation with LV fractional shortening., Conclusions and Clinical Importance: Aortic annular plane systolic excursion is an easily acquired echocardiographic variable and might be a new measurement of LV systolic performance in cats with HCM., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Objective: To retrospectively compare efficacy of a continuous positive airway pressure (CPAP) helmet against standard oxygen supplementation (STD) administered by nasal cannulae in dogs with acute cardiogenic pulmonary edema (ACPE)., Animals: 83 dogs (STD group, n = 41; CPAP group, 42) hospitalized for ACPE (January 2019 to April 2021)., Methods: Mean respiratory rate, heart rate, systolic arterial pressure, and rectal body temperature were compared between and within groups before and at 1 (T1), 2 (T2), 3 (T3), 6 (T6), and 12 (T12) hours from the beginning of STD/CPAP therapy. Duration of oxygen supplementation, hospitalization time, total diuretic dose, additional pharmacological interventions and mortality rates were compared between groups. The veterinary bedside lung ultrasound in emergency score, thoracic radiographs, and arterial blood parameters were compared between and within groups before and at the end of CPAP/STD therapy., Results: Within both groups, clinical parameters decreased during the observation period. Mean respiratory rate and heart rate were significantly lower in the CPAP group than the STD group at T1, T2, T3, T6, and T12. Mean systolic arterial pressure was significantly lower in the CPAP group than the STD group at T2, T3, T6, and T12. Mean oxygen supplementation duration, cumulative loop diuretic dose, and both veterinary bedside lung ultrasound in emergency score and arterial PaCO2 at the end of CPAP/STD therapy were significantly lower in the CPAP group than the STD group. No significant differences were observed in hospitalization time and mortality rates., Clinical Relevance: The addition of helmet CPAP compared with standard oxygen administration showed a faster clinical improvement with lower cumulative loop diuretic and shorter oxygen supplementation in dogs hospitalized for ACPE.

Pregnancy is associated with adaptation of the left ventricular (LV) function. Due to differences between breeds in baseline echocardiographic values and specific predispositions for myocardial diseases, breed-specific echocardiographic parameters may be helpful to evaluate whether the systolic function varies during pregnancy. This study enrolled nine healthy Great Dane bitches with uncomplicated pregnancy. Echocardiographic M-mode and B-mode data were collected before ovulation and within 7 days of the predicted parturition term. Evaluated parameters were: LV dimension in diastole (LVd) and systole (LVs), end-diastolic (EDVI) and end-systolic (ESVI) volumes indexed to body surface area (BSA), end-diastolic (EDV) and end-systolic (ESV), end-point-septal-separation (EPSS), left atrium to aortic root ratio (LA/Ao), sphericity index (SI), ejection fraction (EF), fractional shortening (FS), stroke volume (SV), heart rate (HR), and cardiac output (CO). The ANOVA showed a statistical effect of the age of gestation ( p < 0.01) on the increase of diastolic dimensions and functional parameters and on the decrease of systolic dimensions. The CO increase parallels the rise in SV and HR ( p < 0.01). No statistical differences were observed for EPSS, LA/Ao, and SI. The changes in cardiac chambers and function are likely to reflect maternal adaptation to allow the fetal development in uncomplicated pregnancy. The present study provides specific echocardiographic values in uncomplicated pregnancy of Great Danes, showing that the systolic function is enhanced and that the increase in preload, observed during gestation, is the likely mechanism.

Background: Cats with hypertrophic cardiomyopathy (HCM) have decreased left ventricular (LV) longitudinal deformation detected by mitral annular plane systolic excursion (MAPSE) and speckle tracking echocardiography. People with preclinical HCM have decreased systolic LV longitudinal and radial strain (S) and strain rate (SR), with preserved circumferential S and SR., Hypothesis/objectives: Cats with preclinical HCM have decreased systolic LV deformation compared to normal cats., Animals: Seventy-three client-owned cats with (n = 37) and without (n = 36) preclinical HCM., Methods: Retrospective echocardiographic study. Left and right ventricular longitudinal S and SR, LV radial and circumferential S and SR were calculated by STE. Left ventricular mass was also calculated. Correlation between STE variables and LV hypertrophy was determined and receiver-operating characteristic (ROC) curves were plotted for prediction of HCM., Results: Cats with HCM had smaller absolute longitudinal S (-14.8 ± 3.3% vs -19.7 ± 2.7%, P < .001), longitudinal SR (-2.36 ± 0.62 vs -2.95 ± 0.68 second -1 , P < .001), radial S (46.2 ± 21.3% vs 66.7 ± 17.6%, P < .001), and radial SR (5.60 ± 2.08 vs 6.67 ± 1.8 second -1 , P < .001) compared to healthy controls. No difference was observed for circumferential S and SR. Cats with HCM had greater LV mass (13.2 ± 3.7 g vs 8.6 ± 2.7 g, P < .001). The ROC with the greatest area under the curve (AUC) for the identification of HCM (0.974) was plotted from a logistic regression equation combining LV mass, MAPSE at the free wall, and LV internal diameter in diastole (LVIDd)., Conclusions and Clinical Importance: Cats with preclinical HCM have decreased long axis and radial deformation. Decreased longitudinal deformation and decreased LVIDd are factors that would support a diagnosis of HCM., (© 2019 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Objectives: Large studies focusing on restrictive cardiomyopathy (RCM) in the cat are scarce. The aims of this retrospective study were to describe epidemiological characteristics and to analyse prognostic factors affecting survival in cats with RCM., Methods: The clinical archives of the Gran Sasso Veterinary Clinic (Milan, Italy) and of the cardiology unit of the Department of Veterinary Medicine (University of Milan, Italy) from 1997-2015 were reviewed for all cats diagnosed with RCM based on an echocardiographic examination (left atrial/biatrial enlargement, normal left ventricle wall thickness, normal or mildly decreased systolic function and restrictive left ventricle filling pattern with pulsed Doppler echocardiography)., Results: The study population comprised 90 cats (53 male, 37 female) with an echocardiographic diagnosis of RCM. Most were domestic shorthairs (n = 60) with a mean ± SD age of 10.0 ± 4.3 years and a median weight of 3.8 kg (interquartile range 3.2-5 kg). Most cats were symptomatic (n = 87). The most common clinical sign was respiratory distress (n = 75). Follow-up was available for 60 cats and the median survival time (MST) was 69 days (95% confidence interval [CI] 0-175 days). Cardiac-related death occurred in 50 cats. In the multivariate Cox analysis only respiratory distress showed a statistically significant effect on survival. The cats without respiratory distress showed an MST of 466 days (95% CI 0-1208); cats with respiratory distress showing an MST of 64 days (95% CI 8-120; P = 0.011)., Conclusions and Relevance: RCM can be considered an end-stage condition associated with a poor prognosis, with few cats not showing clinical signs and surviving >1 year. Most cats died of cardiac disease within a very short time.

Background: Left ventricular (LV) systolic dysfunction is associated with increased risk of death in cats with hypertrophic cardiomyopathy (HCM). Mitral and tricuspid annular plane systolic excursion (MAPSE and TAPSE, respectively) are measures of longitudinal systolic function and are reduced in human patients with HCM., Hypotheses: Cats with HCM have lower MAPSE and TAPSE compared to control cats; lower MAPSE and TAPSE are associated with the presence of congestive heart failure (CHF) and reduced survival time., Animals: 64 cats with HCM and 27 healthy cats. Forty-five cats with HCM were not showing clinical signs, and 19 had CHF., Methods: Retrospective study. Anatomic M-mode from the left apical 4-chamber view was used to record MAPSE from the free wall (MAPSE FW) and septum (MAPSE IVS) and TAPSE., Results: Compared to controls, cats with HCM had lower MAPSE IVS (controls 5.2 [4.6-5.6] mm, asymptomatic HCM 4.7 [4.1-5.2] mm, HCM with CHF 2.6 [2.5-3.2] mm, P < .001), MAPSE FW (controls 5.9 [5.3-6.2] mm, asymptomatic HCM 4.7 [4.1-5.1] mm, HCM with CHF 2.8 [2.4-3.2] mm) and TAPSE (controls 8.6 [7.4-10.2] mm, asymptomatic HCM 7.2 [6.3-8.2] mm, HCM with CHF 4.6 [4.1-5.4] mm), with the lowest in the CHF group. Univariate survival analysis showed a shorter survival in cats displaying lower MAPSE IVS, MAPSE FW, and TAPSE., Conclusions and Clinical Importance: MAPSE and TAPSE were lower in cats with HCM than in control cats and were lowest in CHF, suggesting that systolic longitudinal dysfunction is present in cats with HCM. MAPSE and TAPSE have potential prognostic significance., (Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: Myxomatous mitral valve disease (MVD) is the most common acquired heart disease in dogs, and the Cavalier King Charles Spaniel (CKCS) is the most studied breed because of the high prevalence, early onset and hereditary component evidenced in the breed. MVD has different severity levels, and there are many practical limitations in identifying its asymptomatic stages. Proteomic techniques are valuable for studying the proteins and peptides involved in cardiovascular diseases, including the period prior to the clinical onset of the disease. The aim of this study was to identify the serum proteins that were differentially expressed in healthy CKCS and those affected by MVD in mild to severe stages. Proteomics analysis was performed using two-dimensional gel electrophoresis separation and a bioinformatics analysis for the detection of differentially expressed spots. In a comparative analysis, protein spots with a p < 0.05 (ANOVA) were considered statistically significant and were excised from the gels for analysis by MALDI-TOF-MS for protein identification., Results: Eight proteins resulted differentially expressed among the groups and significantly related to the progression of the disease. In mild affected group versus healthy dogs complement factor H isoform 2, inhibitor of carbonic anhydrase, hemopexin, dystrobrevin beta isoform X7 and CD5 molecule-like resulted to be down-regulated, whereas fibronectin type-III domain-containing protein 3A isoform X4 was up-regulated. In severe affected dogs versus healthy group complement factor H isoform 2, calpain-3 isoform X2, dystrobrevin beta isoform X7, CD5 molecule-like and l-2-hydroxyglutarate dehydrogenase resulted to be down-regulated. Complement factor H isoform 2, calpain-3 isoform X2, dystrobrevin beta isoform X7, CD5 molecule-like and hydroxyglutarate dehydrogenase were found to be down-regulated in mild affected group versus healthy dogs. All of these proteins except complement factor H followed a decreasing trend according to the progression of the pathology., Conclusion: The differential expression of serum proteins demonstrates the possibility these might be valuable for the detection and monitoring of the disease. Further longitudinal studies are required to determine whether differential protein expression occurs sufficiently early in the progression of the disease and with sufficient predictive value to allow proteomics analysis to be used as an early detection and on-line diagnostic tool.

Background: Veterinary literature lacks data about cardiovascular-renal disorders (CvRD) and cardiorenal-anemia syndrome (CRAS) in dogs., Hypothesis: A direct correlation exists between ACVIM class and IRIS stage; chronic kidney disease (CKD) complicates chronic mitral valve disease (CMVD) more often than does anemia in dogs., Animals: One hundred and fifty-eight client-owned dogs with CMVD., Methods: Signalment, physical examination findings, electrocardiography, thoracic radiographs, echocardiography, and blood analysis were retrospectively evaluated to assess the prevalence of CKD and anemia in dogs with CMVD and to investigate the relationships among ACVIM class, IRIS stage, and survival., Results: The prevalence of CKD and anemia in dogs with CMVD was significantly higher than in the general population of dogs. Dogs being treated for heart failure had a significantly higher prevalence of CKD than did dogs that had not received treatment. A statistically significant direct correlation was found between ACVIM class and IRIS stage. Severe heart disease, severe renal disease or both, furosemide administration, and advanced age at diagnosis of heart disease were associated with shorter survival time. Survival time of dogs affected by CvRD was statistically shorter than survival time of dogs affected by CMVD alone., Conclusion and Clinical Relevance: Chronic mitral valve disease is associated with increased prevalence of CKD and anemia in dogs. Treatment for medical management of heart failure may play a role in inducing CKD. Class of heart disease and IRIS stage were directly correlated. Cardiovascular-renal disorders decrease survival time compared to the only presence of CMVD alone, whereas anemia does not play a central role in worsening heart function., (Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Objectives: Feline cardiomyopathies (CMs) represent a heterogeneous group of myocardial diseases. The most common CM is hypertrophic cardiomyopathy (HCM), followed by restrictive cardiomyopathy (RCM). Studies comparing survival and outcome for different types of CM are scant. Furthermore, little is known about the cardiovascular consequences of systemic diseases on survival. The aim of this retrospective study was to compare survival and prognostic factors in cats affected by HCM, RCM or secondary CM referred to our institution over a 10 year period., Methods: The study included 94 cats with complete case records and echocardiographic examination. Fifty cats presented HCM, 14 RCM and 30 secondary CM., Results: A statistically significant difference in survival time was identified for cats with HCM (median survival time of 865 days), RCM (273 days) and secondary CM (<50% cardiac death rate). In the overall population and in the primary CM group (HCM + RCM), risk factors in the multivariate analysis, regardless of the CM considered, were the presence of clinical signs, an increased left atrial to aortic root (LA/Ao) ratio and a hypercoagulable state., Conclusions and Relevance: Primary CMs in cats share some common features (ie, LA dimension and hypercoagulable state) linked to feline cardiovascular physiology, which influence survival greatly in end-stage CM. The presence of clinical signs has to be regarded as a marker of disease severity, regardless of the underlying CM. Secondary CMs are more benign conditions, but if the primary disease is not properly managed, the prognosis might also be poor in this group of patients., (© ISFM and AAFP 2015.)

Background: Patent ductus arteriosus (PDA) is one of the most common congenital heart defects in dogs. Advanced echocardiographic techniques such as speckle-tracking echocardiography (STE) have not been extensively used to evaluate cardiac function in affected dogs., Hypothesis: Advanced echocardiographic techniques are more sensitive than standard echocardiographic techniques in analyzing systolic function in dogs with PDA., Animals: Forty-four client-owned dogs: 34 dogs with PDA (preoperative evaluation) and 10 healthy sex- and weight-matched controls., Methods: Prospective study. Dogs were recruited over a 2-year period. Complete echocardiographic evaluation was performed, including conventional (end-diastolic volumes indexed to body surface area in B and M-mode [EDVIB /M ], end-systolic volumes indexed to body surface area in B and M-mode [ESVIB /M ], allometric scaling in diastole and systole [AlloD/S], pulmonary flow to systemic flow [Qp/Qs], ejection fraction [EF] and fractional shortening [FS]) and speckle-tracking echocardiography ([STE]: global longitudinal, radial and circumferential strain [S] and strain rate [SR])., Results: Dogs with PDA had significantly different EDVIB /M , ESVIB /M , AlloD/S, Qp/Qs and all STE-derived parameters (global longitudinal S and SR, global circumferential S and SR, global radial S and SR)compared to healthy dogs. No correlation was found between standard techniques (EDVIB /M , ESVIB /M , AlloD/S, Qp/Qs) and STE-derived parameters (global longitudinal, circumferential and radial S and SR)., Conclusion and Clinical Importance: Conventional parameters routinely used to assess systolic function (EF and FS) were not different between the groups; STE-derived parameters identified subtle changes in cardiac systolic function and contractility between the 2 groups of dogs. Based on these findings, STE may be a more appropriate tool to assess cardiac contractility in dogs with PDA., (Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: Patent ductus arteriosus (PDA) is 1 of the most common congenital heart defects in dogs and percutaneous closure is effective in achieving ductal closure; PDA closure is associated with abrupt hemodynamic changes., Hypothesis: A marked decrease in standard parameters of systolic function as assessed by M- or B-mode echocardiography after PDA closure was identified in previous studies. Speckle tracking echocardiography can provide further insight into the effect of PDA closure on cardiac mechanics in dogs affected by PDA., Animals: Twenty-five client-owned dogs with PDA., Methods: Prospective study. Dogs were recruited over a 2-year period. Complete echocardiographic evaluation was performed before and 24 hours after PDA closure, including standard (end-diastolic volumes indexed to body surface area in B- and M-mode [EDVIB /M ], end-systolic volumes indexed to body surface area in B- and M-mode [ESVIB /M ], allometric scaling in diastole [AlloD] and systole [AlloS], pulmonary flow to systemic flow [Qs/Qp], ejection fraction [EF], and fractional shortening [FS]), and advanced speckle-tracking echocardiography (STE): global longitudinal, radial, circumferential and transverse strain (S), and strain rate (SR)., Results: Patent ductus arteriosus closure was associated with statistically significant decreases in EDVIM /B and ESVIM /B , AlloD and AlloS, SI, EF, and FS. A statistically significant decrease in the absolute values of radial, transverse, and circumferential S and SR was observed, whereas longitudinal S and SR did not change significantly., Conclusion and Clinical Importance: Patent ductus arteriosus closure by percutaneous approach is associated with marked decreases of conventional echocardiographic parameters as a result of the changes in loading conditions, but no evidence of systolic dysfunction was identified by means of STE, as none of the S and SR values were below reference ranges. In the short term, contractility is enhanced in the long axis (long S/SR values were not statistically different before and after closure) and decreases to normal values in short axis (circumferential, radial, and transversal S/SR decreased to normal reference range)., (Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: Quantitative and semiquantitative methods have been proposed for the assessment of MR severity, and though all are associated with limitations. Measurement of vena contracta width (VCW) has been used in clinical practice., Objective: To measure the VCW in dogs with different levels of MR severity., Animals: Two hundred and seventy-nine dogs were classified according to 5 levels of MR severity., Methods: This was a retrospective study. EROA and regurgitant volume calculated by the PISA method, were measured and indexed to BSA. Descriptive statistics were calculated for VCW and VCW index for all categories of MR severity. Spearman's rank correlation coefficients (ρs ) were calculated to compare the results of the different methods (VCW and VCW index vs RV PISA, RV PISA index, EROA, EROA index), and between VCW and VCW index versus MR severity., Results: All Spearman's rank correlation coefficients were significant (P < .001). The median values of VCW resulted of 2.9 mm (IQR 3.4-2.5) and of 4.6 mm (IQR 5.4-4.1) in the groups previously classified as mild-to-moderate and moderate-to-severe, respectively. The median values of VCW index resulted of 4.4 mm/m(2) (IQR = 5.5-4.2) in mild-to-moderate MR and of 10.8 mm/m(2) (IQR = 12.8-9.4) in moderate-to-severe MR., Conclusion and Clinical Importance: This is not a validation study against any previously validated invasive gold standard, the VCW method has proved easy to employ and it might be an additional tool in quantifying disease severity that supports, rather than replace, data coming from other techniques in daily clinical practice and research., (Copyright © 2014 by the American College of Veterinary Internal Medicine.)