Systolic Function In Dogs Research Articles

Changes in echocardiographic indices and left ventricular strain values by two-dimensional speckle-tracking echocardiography following pre-anesthetic oral pimobendan administration compared with intravenous pimobendan in dogs.

The effects of pre-anesthetic single-dose oral pimobendan during inhalational anesthesia, including the comparison with the effects of single intravenous pimobendan under anesthesia, remain unexplored. Therefore, this study aimed to determine changes in hemodynamic and echocardiographic parameters induced by pre-anesthetic administration of oral pimobendan under isoflurane general anesthesia and to compare them with those induced by intravenous pimobendan. Thirteen clinically normal dogs (4 laboratory and 9 client-owned dogs) with no clinical signs and not on any medical treatment were included. Anesthesia was performed three times: no pimobendan (Control), oral pimobendan (PIMO PO, 0.3 mg/kg), and intravenous pimobendan (PIMO IV, 0.15 mg/kg). Echocardiographic and hemodynamic parameters were monitored at 30-min intervals in all groups. Compared to the Control group, end-systolic volume index (ESVI) and normalized left ventricular internal diameter at end-systole (LVIDSN) were significantly lower, and fractional shortening (FS) and ejection fraction (EF) were significantly higher in the PIMO PO and IV groups (p < 0.001). Global radial strain (GRS) was significantly higher in the PIMO PO and IV groups (p = 0.015). Under general anesthesia, oral pimobendan preserved LV systolic and myocardial function in a manner comparable to intravenous pimobendan. Pre-anesthetic administration of oral pimobendan can be used to compensate for cardiac systolic function in dogs who require therapeutic and diagnostic procedures under general anesthesia with potential risk of circulatory failure.

Assessment of left and right ventricular systolic function in dogs with multicentric lymphoma

ObjectiveMyocardial dysfunction in cardio-oncology is generally thought to be related to the cardiotoxicity of chemotherapy treatment. However, it is known that some tumors have direct effects on myocardial function. These effects have already been studied in man, but there are no publications of these of the effects in dogs. Novel advanced echocardiographic techniques may allow early detection of myocardial dysfunction when compared to conventional echocardiographic techniques. This study aims to assess myocardial systolic function in dogs with multicentric lymphoma prior to initiation of chemotherapy. AnimalsFifteen dogs with multicentric lymphoma and nineteen healthy dogs. MethodsCase-control study. Dogs with multicentric lymphoma and healthy control dogs underwent physical examination, electrocardiography, systolic blood pressure measurement, standard and speckle tracking echocardiography to assess biventricular systolic function. ResultsThere were no differences between groups in terms of ejection fraction, fractional shortening, left ventricular systolic and diastolic diameter, tricuspid annular plane systolic excursion, mitral annular plane systolic excursion and fractional area change of the right ventricle (RV). However, there was a reduction in the values of global circumferential strain (p = 0.0003), RV strain (p = 0.01) and RV tissue motion annular displacement (p < 0.05) in the dogs with lymphoma when compared to the control group. ConclusionsSpeckle tracking techniques appear to demonstrate early systolic dysfunction, primarily affecting the RV, in dogs with lymphoma prior to chemotherapy treatment.

Systolic function in dogs with pulmonic stenosis of different severities and the effect of balloon valvuloplasty

Introduction/objectivesPulmonic stenosis (PS) is one of the most common congenital heart diseases in dogs leading to right ventricular (RV) pressure overload, myocardial remodeling, and potential RV dysfunction. Our objectives were to investigate the extent of RV systolic dysfunction in canine PS and to examine the immediate influence of balloon valvuloplasty (BV) on systolic function. Animals, materials and methodsThis prospective study evaluated 72 dogs with PS and 86 healthy dogs. Echocardiographic parameters of systolic function included normalized tricuspid annular plane systolic excursion (N-TAPSE), normalized systolic myocardial tissue Doppler velocity of the lateral tricuspid annulus (N-RVFW-S′), fractional area change, and speckle-tracking longitudinal endocardial RV strain. Forty-four dogs underwent BV and were re-examined after surgery. ResultsSystolic function at the basal segment of the RV was significantly lower in the PS group when compared to healthy dogs (mean N-TAPSE 4.29 ± standard deviation 1.18 mm/kg0.285 vs. 5.60 ± 1.29 mm/kg0.285; median N-RVFW-S′ 5.28 [lower-upper 25% quantile 4.35–6.43 cm/s/kg0.186] vs. 7.82 [6.73–8.79 cm/s/kg0.186]; all P<0.001). Global longitudinal RV endocardial strain showed no significant difference between the two groups (−28.50 ± 6.23% vs. 28.61 ± 4.64%; P=0.886), but segmental strain analyses revealed basal hypo- and potential compensatory hyperkinesis of the apical RVFW. Furthermore, BV affected most parameters of systolic function, but not the segmental strain values and N-TAPSE. ConclusionsRight ventricular basal longitudinal systolic function is decreased in dogs with PS in comparison to a healthy cohort. Regional and global function does not necessarily coincide.

Assessment of longitudinal systolic function using tissue motion annular displacement in dogs with degenerative mitral valve disease

IntroductionAlthough degenerative mitral valve disease (DMVD) is essentially a disorder of the valve, the progression of the disease leads to structural myocardial changes that may compromise left ventricular systolic function. Tissue motion annular displacement (TMAD) is a surrogate for longitudinal fiber function based on speckle tracking assessment of the movement of the mitral annulus toward the apex during systole. The aim of this study was to evaluate longitudinal systolic function with TMAD in dogs with DMVD. AnimalsNinety-four dogs with DMVD and 32 healthy dogs. MethodsProspective cross-sectional observational study. Dogs with DMVD of various American College of Veterinary Internal Medicine classification stages and healthy control dogs underwent physical examination, electrocardiography, systolic blood pressure measurement, as well as a standard and speckle tracking echocardiography. Global longitudinal strain (GLS) and TMAD were used to assess longitudinal systolic function. ResultsThe global TMADmm and global TMAD% were higher in American College of Veterinary Internal Medicine B2 animals than in the stage CD. Global TMAD (mm/kg,mm/bodyweight3, mm/m2) were correlated with GLS and ejection fraction. Global TMAD (mm/kg,mm/m2,%) and GLS were influenced by sex. In addition, systolic blood pressure influenced GLS (P < 0.01; r = −0.23), global TMADmm/kg (P = 0.017; r = −0.21) and global TMADmm/m2 (P = 0.031; r = −0.19). Tissue motion annular displacement was fast to be performed and produced good repeatability in dogs with DMVD. ConclusionsGlobal TMAD (mm,%), was reduced in DMVD dogs with clinical signs of heart failure compared with stage B2. Tissue motion annular displacement was shown to be a repeatable technique for evaluation of longitudinal systolic function in dogs with DMVD.

Conventional and advanced echocardiographic assessment of systolic function in dogs sedated with dexmedetomidine or acepromazine

Dexmedetomidine and acepromazine, sedatives commonly used in dogs have opposite vascular effects, resulting in afterload increase and decrease, respectively. This could variably affect systolic myocardial function. Previous echocardiographic studies assessing the cardiovascular effects of these drugs used conventional echocardiography, while advanced techniques such as speckle tracking echocardiography (STE) and tissue Doppler imaging (TDI), which are known to provide a more accurate assessment of systolic function, have been rarely used for this aim. Moreover, in the few studies using advanced techniques, the drugs where combined with opioids. Therefore, the main objective of this prospective study was to assess systolic myocardial function by conventional and advanced echocardiography (STE and TDI), in dogs sedated exclusively with dexmedetomidine or acepromazine not combined with other drugs. Twenty healthy dogs were randomly divided into two groups, Group A (acepromazine, 20 μg/kg IM), and Group D (dexmedetomidine, 5 μg/kg IM), cardiovascular parameters were assessed before sedation (T0), and thirty minutes afterwards (T1). Systolic arterial pressure and heart rate decreased in both groups at T1 as compared to T0. Only one conventional echocardiographic raw variable (left ventricular internal dimension in systole) and three out of five advanced echocardiographic variables (radial TDI systolic velocities at the epicardial region of the left ventricular free wall, longitudinal TDI systolic velocities of the septal mitral valve annulus and the STE-derived left ventricular global strain), were affected in Group D. A systolic impairment was observed in Group D and better estimated by advanced echocardiography. In Group A, only the end diastolic voume index (conventional echocardiography) was decreased. Both protocols seem to induce echocardiographic changes more likely secondary to their vascular action.

Systolic dysfunction by two-dimensional speckle tracking echocardiography in dogs with parvoviral enteritis

Introduction/objectivesParvoviral enteritis (PVE) can cause either primary or secondary myocardial injury; the latter is associated with systemic inflammatory response syndrome and sepsis. Strain (St) and strain rate (SR) are relatively new speckle tracking echocardiographic (STE) variables used to assess myocardial function and are less influenced by preload and volume status than are conventional variables. The aim of this study was to evaluate systolic function in dogs with PVE using two-dimensional STE. AnimalsForty-five client-owned dogs were included. Materials and methodsDogs were classified into four groups: healthy (n = 9), PVE-mild (n = 15), PVE-severe (n = 13) and PVE-died (n = 8). Left ventricular global and segmental myocardial St and SR were assessed in radial, circumferential and longitudinal axes in the right parasternal transverse and apical 4-chamber views. In the circumferential and longitudinal axes, the value of each segment was determined separately at the endocardial and epicardial levels. ResultsCompared to healthy animals, all dogs with PVE showed significantly impaired St and SR values, mainly for PVE-severe and PVE-died groups. Moreover, the lowest SR value was observed in the circumferential axis at the mid-septal epicardial segment in the PVE-died group. For this variable, a cut-off value of 0.95 s−1 demonstrated 100% sensitivity and specificity for distinguishing between PVE-severe and PVE-died groups. ConclusionsIn the present study, all dogs with PVE developed systolic dysfunction, which was more severe in non-survivors. Assessment of St and SR in dogs with PVE might be clinically useful for evaluating haemodynamic status and developing suitable therapeutic strategies to improve prognosis.

Left ventricular systolic function in dogs with pulmonic stenosis.

Background and Aim:Pulmonic stenosis (PS) is the most common congenital heart disease in dogs. This condition causes right ventricle (RV) overload and disrupts overall systolic function. The aim of this study was to examine the alterations of cardiac electrical activity and mechanical function in dogs with PS compared to normal healthy dogs.Materials and Methods:The ventricular systolic function of dogs with PS was studied. Dogs were divided into two groups, PS (n=13) and control (CONT) (n=12). Measurements of blood pressure, electrocardiography (ECG), and echocardiography were performed.Results:PS dogs had exercise intolerance, with six experiencing syncope. ECG of PS dogs showed higher amplitudes of P, S, and T waves (p<0.01), and a lower R:S ratio (p<0.001) with longer QRS duration (p<0.001) compared to CONT dogs. Echocardiography demonstrated that the pulmonic flow velocity and pressure gradient (PG) between the RV and the pulmonary artery of PS dogs were significantly higher than CONT dogs (p<0.001). The RV free wall thickness to the left ventricular posterior wall thickness ratio and the right atrium to the left atrium diameter ratio was higher (p<0.001), while interventricular septum (IVS) was thicker (p<0.01) in PS dogs compared with CONT dogs (p<0.001). The systolic function in PS dogs showed higher pulmonic valve velocity time integral (PVVTI) value (p<0.001) and longer pulmonic valve ejection time (ET) (p<0.05) than CONT dogs. However, aortic valve VTI (AVVTI) value and aortic valve ET were not significantly different between the groups, although fractional shortening in PS dogs was higher. In PS dogs, PG showed a significant positive correlation with PVVTI: AVVTI ratio (p<0.05).Conclusion:PS had prolonged pulmonic valve opening. The thickening of the RV wall and IVS can cause a detrimental reduction of the left ventricular preload in PS dogs.

Use of 2-dimensional speckle-tracking echocardiography to assess left ventricular systolic function in dogs with systemic inflammatory response syndrome.

BackgroundEarly identification of systolic dysfunction in dogs with systemic inflammatory response syndrome (SIRS) potentially could improve the outcome and decrease mortality.ObjectiveTo compare 2‐dimensional speckle tracking (2D‐STE) with 2‐dimensional (2D) and M‐mode echocardiography in the evaluation of systolic function in SIRS dogs.AnimalsSeventeen SIRS and 17 healthy dogs.MethodsProspective observational case‐control study. Each dog underwent physical examination, conventional echocardiography, 2D‐STE, and C‐reactive protein measurement.ResultsDogs with SIRS had lower 2D‐STE ejection fraction (X4D‐EF; 44 ± 8 versus 53 ± 8; P = .003), endocardial global longitudinal strain (ENDO‐G‐Long‐St; −14.6 ± 3.2 versus −18.5 ± 4.1; P = .003), and normalized left ventricular diameter in diastole (1.38 ± 0.25 versus 1.54 ± 0.17; P = .04) and systole (0.85 ± 0.18 versus 0.97 ± 0.11; P = .03) as compared to healthy dogs. Simpson method of disks (SMOD) right parasternal EF (55 ± 9 versus 60 ± 6; P = .07) and end systolic volume index (ESVI; 23 ± 10 versus 21 ± 6; P = .61), SMOD left apical EF (59 ± 9 versus 59 ± 6; P = .87) and ESVI (20 ± 8 versus 22 ± 6; P = .25), fractional shortening (FS; 34 ± 5 versus 33 ± 4; P = .39), M‐mode EF (64 ± 7 versus 62 ± 5; P = .35), and ESVI (23 ± 11 versus 30 ± 9; P = .06) were not significantly different between SIRS and control group, respectively.Conclusion and Clinical ImportanceSpeckle tracking X4D‐EF and ENDO‐G‐Long‐St are more sensitive than 2D and M‐Mode FS, EF, and ESVI in detecting systolic impairment in dogs with SIRS.

Echocardiographic evaluation of the right ventricular dimension and systolic function in dogs with pulmonary hypertension.

BackgroundRight ventricular (RV) enlargement and dysfunction are associated with prognosis in humans with pulmonary hypertension (PH).Hypothesis/ObjectivesTo assess RV size and systolic function in dogs with PH and to determine if they are associated with disease severity and right‐sided congestive heart failure (R‐CHF).Animals89 dogs with PH and 74 healthy dogs.MethodsProspective observational study. PH was classified according to the tricuspid regurgitation pressure gradient. RV end‐diastolic area (RVEDA) index was calculated as RVEDA divided by body surface area. RV systolic function was assessed with the tricuspid annular plane systolic excursion (TAPSE) and the RV fractional area change (FAC) normalized for body weight (TAPSEn and FACn, respectively).ResultsRVEDA index was higher in dogs with moderate PH (10.8 cm2/m2; range, 6.2‐14.4 cm2/m2) and severe PH (12.4 cm2/m2; range, 7.7‐21.4 cm2/m2) than in those with mild PH (8.4 cm2/m2; range, 4.8‐11.6 cm2/m2) and control dogs (8.5 cm2/m2; range, 2.8‐11.6 cm2/m2; P < .001). RVEDA index was significantly higher in dogs with R‐CHF (13.7 cm2/m2; range, 11.0‐21.4 cm2/m2) than in dogs without R‐CHF (9.4 cm2/m2; range, 4.8‐17.1 cm2/m2; P < .001). The severity of tricuspid regurgitation (TR) was the only independent predictor of the RVEDA index (P < .001). TAPSEn and FACn were not significantly different among varying degrees of PH severity and between dogs with and without R‐CHF.Conclusions and Clinical ImportanceThe RVEDA index can be used to evaluate RV size in dogs. It can provide additional information in dogs with PH and predict R‐CHF. Severity of TR is the main determinant of RV enlargement in dogs with PH.

Right ventricular outflow tract fractional shortening: an echocardiographic index of right ventricular systolic function in dogs with pulmonary hypertension

ObjectivesTo create reference intervals for right ventricular outflow tract fractional shortening (RVOT-FS) in healthy dogs and examine diagnostic performance of this index in dogs with pulmonary hypertension (PH). In addition, we examine the impact of myxomatous mitral valve disease (MMVD) without PH on RVOT-FS. Animals, materials and methodsThe study population included 52 healthy adult dogs, 51 dogs with MMVD but without PH, and 51 dogs with PH. This is a prospective study. Complete echocardiographic evaluations were performed on all dogs. Right ventricular outflow tract fractional shortening was obtained by two-dimensional guided M-mode recordings from the right parasternal short axis view. Right ventricular outflow tract fractional shortening was evaluated in healthy dogs of various breeds, and reference intervals were generated. We examined the effect of PH on RVOT-FS with receiver operating characteristic analysis and evaluated the effect of MMVD on RVOT-FS in dogs without PH. Intraobserver and interobserver reproducibility was calculated. ResultsHealthy dogs had RVOT-FS > 44%. Right ventricular outflow tract fractional shortening values of healthy dogs and MMVD dogs without PH did not differ (p=0.84). In dogs with PH, RVOT-FS decreased with increasing tricuspid regurgitation velocity (p<0.0001). Pimobendan use in dogs with PH increased RVOT-FS as PH worsened. Right ventricular outflow tract fractional shortening was acquired with clinically acceptable intraobserver and interobserver reproducibility. ConclusionsRight ventricular outflow tract fractional shortening is a novel, easy applicable, and repeatable index for evaluating RV systolic function. Studies comparing this index with common echocardiographic indices used to assess RV function in dogs are needed.

Chronic Therapy with Sacubitril/Valsartan Reduces Plasma Troponin-I Level in Dogs with Experimentally-Induced Cardiorenal Syndrome

Introduction Ongoing loss of cardiomyocytes occurs in heart failure (HF) and contributes to progressive worsening of the HF state. Sacubitril/Valsartan (S/Val), a combined angiotensin-II receptor blocker (Val) and neprilysin inhibitor (S) in a 1:1 molar ratio, was shown to reduce the risk of cardiovascular death or HF hospitalization in patients with HF and reduced left ventricular (LV) ejection fraction (EF). Chronic therapy with S/VAL was also shown to improve LV systolic function in dogs with experimentally-induced cardiorenal syndrome. Objective This study tested the hypothesis that chronic therapy with S/Val in dogs with cardiorenal syndrome ameliorates ongoing loss of cardiomyocytes as evidenced by lowering plasma levels of troponin-I (TnI). Methods 14 dogs with coronary microembolization-induced HF and renal dysfunction induced by unilateral nephrectomy with imposed stenosis of the contralateral renal vein, were randomized to 3 months therapy with S/Val (100 mg once daily, n=7) or no therapy (control, CON, n=7). LV EF was measured before (PRE) and at 12 weeks after initiating therapy with S/Val (POST). High sensitivity plasma TnI was measured when animals were normal (NL) and again after induction of cardiorenal syndrome and subsequently at 2, 4, and 12 weeks after initiating S/Val therapy. TnI levels were determined using a commercially available Ultra-Sensitive Dog Cardiac Troponin-I Elisa kit and the concentration was expressed in ng/ml. Results In CON dogs, LV EF was unchanged from PRE to POST (35 ± 1 vs. 36 ± 1 %) but increased significantly from PRE to POST in S/Val-treated dogs (34 ± 1 vs. 41 ± 2 %, p Table ) and remained elevated throughout the follow-up period. In contrast, in S/Val-treated dogs, TnI levels decreased gradually during the therapy period ( Table ). Conclusions In dogs with cardiorenal syndrome, S/Val reduces plasma TnI levels compared to untreated CON. This observations suggests that chronic therapy with S/Val attenuates or prevents ongoing loss cardiomyocytes, a characteristic feature of the HF state.

Acute echocardiographic effects of sotalol on ventricular systolic function in dogs with ventricular arrhythmias.

BackgroundSotalol is a commonly used antiarrhythmic drug that may alter ventricular function.ObjectiveTo determine the effect of sotalol on echocardiographic indices of ventricular systolic function in dogs with ventricular arrhythmias.AnimalsThirty‐five client‐owned dogs with ventricular arrhythmias.MethodsDogs with ventricular arrhythmias (n = 27) had an echocardiogram and 5‐minute ECG performed at baseline and 2‐4 hours post‐sotalol (2‐2.5 mg/kg PO once). Eight additional dogs underwent the same protocol but did not receive sotalol (within‐day variability controls). Left ventricular (LV) internal dimension at end‐systole normalized to bodyweight (LVIDs_N), LV ejection fraction (LV EF), LV shortening area, LV fractional shortening, tricuspid annular plane systolic excursion (TAPSE), and right ventricular systolic myocardial velocity were evaluated as indices of systolic function.ResultsAll indices except TAPSE had mild decreases in systolic function post‐sotalol (all P ≤ .0007) compared with baseline but only the percent change in LVIDs_N and LV EF were significantly (P ≤ .0079) different from the percent change of the same indices in control dogs. Sinus heart rate, ventricular premature complexes/5‐minutes, and arrhythmia grade also were decreased post‐sotalol (all P ≤ .01) compared with baseline when assessed by a 5‐minutes ECG. No dog experienced an adverse event post‐sotalol, including dogs with systolic dysfunction or atrial enlargement.Conclusions and Clinical ImportanceA single dose of sotalol may cause a mild decrease in LV systolic function in dogs with ventricular arrhythmias. Sotalol appears to be well tolerated, even in dogs with atrial enlargement or systolic dysfunction.

Assessment of longitudinal systolic function using tissue motion annular displacement in healthy dogs

IntroductionLeft ventricular systolic function is one of the main parameters studied in echocardiography. Longitudinal systolic function, however, is less commonly evaluated in routine examinations but may provide early information on systolic dysfunction. The movement of the mitral annulus toward the apex has already been determined as a method for evaluation of longitudinal systolic function in dogs, but the study of this movement by speckle tracking with the tissue motion annular displacement (TMAD) technique has not yet been evaluated. AnimalsOne hundred fifty-three client-owned healthy dogs. MethodsCross-sectional study. One hundred fifty-three client-owned healthy dogs underwent physical examination, electrocardiography, blood pressure measurement, and a standard and speckle tracking echocardiography. Systolic function was evaluated by global longitudinal strain (GLS) and TMAD. These parameters were compared with the standard echocardiographic data. ResultsA correlation was found between GLS, TMAD, and body weight. Tissue motion annular displacement and GLS were significantly correlated (p < 0.001) with other surrogates of systolic function, including ejection fraction and fractional shortening. There were no differences in TMAD between sexes. The coefficient of variation (CV) of the intraobserver evaluation in the global TMAD (CV 4.44) was slightly higher than that in the GLS (CV 3.74). Also, TMAD was not influenced by heart rhythm and could be acquired more rapidly than GLS. ConclusionsTissue motion annular displacement is a rapid and reproducible method for the assessment of left ventricle longitudinal function in healthy dogs. However, more studies are needed to validate the real clinical applicability of TMAD in animals with heart diseases.

Tricuspid annular plane systolic excursion-to-aortic ratio provides a bodyweight-independent measure of right ventricular systolic function in dogs

ObjectivesTo evaluate whether tricuspid annular plane systolic excursion (TAPSE) can be normalized to aortic valve (Ao) measurements in dogs. To determine TAPSE:Ao reference intervals for healthy dogs and examine diagnostic performance of TAPSE:Ao in dogs with pulmonary hypertension (PH). AnimalsOne hundred and thirty-seven healthy adult dogs; 115 dogs with myxomatous mitral valve disease (MMVD) but no PH; 91 dogs with PH. MethodsA combined prospective and retrospective study. Full echocardiographic evaluations were performed on all dogs; TAPSE was indexed to Ao to produce a unitless TAPSE:Ao. Reference intervals for TAPSE:Ao were generated, and TAPSE:Ao was regressed on tricuspid regurgitant jet velocity in dogs with PH and on LA:Ao in dogs with MMVD without PH. Diagnostic test analysis was used to examine the ability of TAPSE:Ao to identify severe PH. An adjusted TAPSE:Ao (TAPSE:Ao(adj)) was derived to account for MMVD in dogs with PH. ResultsThe ratio, TAPSE:Ao, removed the effect of bodyweight from TAPSE measurements. Healthy dogs had TAPSE:Ao > 0.65. The ratio, TAPSE:Ao, showed a linear negative relationship with tricuspid regurgitation velocity and positive relationship with LA:Ao. The adjusted ratio, TAPSE:Ao(adj), increased the sensitivity of diagnosis of PH in dogs with moderate-severe MMVD without affecting the diagnosis of PH in dogs with PH and with no or mild MMVD. ConclusionsThe ratios, TAPSE:Ao and TAPSE:Ao(adj), are a bodyweight-independent means of assessing right ventricular systolic function in dogs and for identifying severe PH in dogs with or without MMVD.

Echocardiographic Estimates of Right Ventricular Systolic Function in Dogs with Myxomatous Mitral Valve Disease.

BackgroundRight ventricular (RV) dysfunction independently predicts outcomes in human myxomatous mitral valve disease (MMVD). There is limited information regarding RV systolic function in dogs with MMVD.HypothesisRight ventricular systolic function differs among stages of disease, decreasing in decompensated MMVD.AnimalsThirty‐sixclient‐owned dogs with MMVD not receiving oral cardiovascular medications.MethodsProspective clinical study. Dogs were categorized according to disease severity as ACVIM Stage B1, B2, or C. Seven echocardiographic indices of RV systolic function were measured. Groups were compared by 1‐way ANOVA and Tukey's HSD test. Frequencies of cases with cardiac remodeling falling outside previously established reference intervals were compared using Fisher's exact test. Intra‐ and interobserver measurement variability was calculated for each RV function index.ResultsThe indices TAPSE (P = 0.029), RV StL (P = 0.012), and RV StRL (P = 0.041) were significantly different between groups. A greater proportion of B2 dogs (7 of 12) had TAPSE values above reference intervals compared with B1 (2 of 12) or C (2 of 12) dogs (P = 0.027). Measurement variability of TAPSE, RV S', and RV StG was clinically acceptable.Conclusions and Clinical ImportanceRight ventricular systolic function differs between stages of MMVD, increasing in stage B2, and declining in stage C. The prognostic importance of RV function indices, particularly TAPSE, might be worth evaluating in dogs with MMVD.

Evaluation of left ventricular systolic function after renal sympathetic denervation in beagles with heart failure by layer-specific two-dimensional speckle tracking imaging

Objective To assess the left ventricular systolic function after renal sympathetic denervation(RSD) in beagles with heart failure by layer-specific two-dimensional speckle tracking imaging. Methods Twenty-three beagles were randomly divided into control group (8 dogs), URSD group (8 dogs) and RSD group (7 dogs). Control group was implanted with pacemakers without pacing, URSD group was implanted with pacemakers and underwent 3 weeks of rapid right ventricular pacing, and RSD group underwent catheter-based RSD bilaterally and was simultaneously implanted with pacemakers. All standard measurements were obtained from the left ventricular short-axis views at the levels of mitral annulus, papillary muscle and apex, and apical four-chamber, two-chamber, and long-axis views. The peak systolic longitudinal strain and circumferential strain of each layer of the left ventricle were measured by layer-specific two-dimensional speckle tracking imaging. Results After 3 weeks, all of the dogs in both the URSD and RSD groups showed lower left ventricular diastolic and systolic function compared with those in the control group, however, the dogs in the RSD group had a higher LV ejection fraction (LVEF) than the dogs in the URSD group(P<0.05). Compared with the control group, the global longitudinal strain, circumferential strain and radial strain all decreased significantly in URSD and RSD groups. The longitudinal strain of endo- and mid-cardium and the circumferential strain in endo-cardium were significantly higher in RSD group than those in URSD group(P<0.05). Conclusions Myocardial systolic function is impaired in dogs with heart failure, layer-specific two-dimensional speckle tracking imaging can provide effective tools to assess the left ventricular systolic function. Renal sympathetic denervation can improve the myocardial systolic function in dogs with heart failure. Key words: Echocardiography; Renal sympathetic nerve; Catheter ablation; Ventricular function, left; Layer-specific speckle tracking imaging

Echocardiographic Assessment of Cardiac Function by Conventional and Speckle-Tracking Echocardiography in Dogs with Patent Ductus Arteriosus.

BackgroundPatent 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.HypothesisAdvanced echocardiographic techniques are more sensitive than standard echocardiographic techniques in analyzing systolic function in dogs with PDA.AnimalsForty‐four client‐owned dogs: 34 dogs with PDA (preoperative evaluation) and 10 healthy sex‐ and weight‐matched controls.MethodsProspective 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]).ResultsDogs 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 ImportanceConventional 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.

(362) - Vepoloxamer (Purified Sodium-Free Poloxamer-188) Improves LV Systolic Function in Dogs with Advanced Heart Failure and Protects Failing Cardiomyocytes from Calcium Overload

(362) - Vepoloxamer (Purified Sodium-Free Poloxamer-188) Improves LV Systolic Function in Dogs with Advanced Heart Failure and Protects Failing Cardiomyocytes from Calcium Overload

Right Vagus Nerve Stimulation With a Novel Self-Sizing Cuff Electrode Improves Left Ventricular Function in Dogs With Heart Failure

Background: Autonomic imbalance namely high sympathetic and low parasympathetic drive, is a maladaptive feature of chronic heart failure (HF) that contributes to progressive left ventricular (LV) dysfunction and remodeling. Electrical right cervical Vagus nerve stimulation (VNS) has been shown to restore autonomic balance and improve LV function in animals with experimentally-induced HF. In this study, we examined the effects of long-term VNS with a novel, self-sizing cuff electrode on LV function and remodeling in dogs with HF. Methods: Studies were performed in 12 dogs with HF (LV ejection fraction, EF !35%) produced by coronary microembolizations. All dogs underwent surgical implantation of the self-sizing cuff electrode around the right Vagus nerve connected to an implantable pulse generator. Delivery of VNS pulses was synchronized to cardiac rhythm assessed from a lead placed in the right ventricle. Dogs were then randomized to no therapy (control, n57) or to active VNS therapy (n55) maintained for 3 months. LV end-diastolic (EDV), end-systolic (ESV) volumes and EF were measured from ventriculograms taken at time of randomization (PRE) and after 3 months of therapy (POST). Results: Results are shown in the table. In controls, heart rate (HR), mean aortic pressure (mAoP), systemic vascular resistance (SVR), EDV, ESV and EF were essentially unchanged between PRE and POST. In VNS-treated dogs, SVR tended to decrease and mAoP and EDV were unchanged. In this group, HR and ESV decreased and EF increased significantly. In 4 dogs, surgical removal of the self-sizing cuff was attempted at the end of 3 months of follow-up and was easily accomplished in every case. Conclusions: Long-term VNS therapy using a novel self-sizing cuff electrode improves LV systolic function in dogs with chronic HF.

Evaluation of the ventricular systolic function in dogs with pulmonary artery hypertension after transcatheter renal sympathetic denervation

Objective To evaluate the effects of transcatheter renal sympathetic denervation (RSD) on the cardiac systolic function of dogs with pulmonary arterial hypertension(PAH) using two-dimensional speckle tracking imaging(2D-STI). Methods Twenty two dogs were divided in to three groups: control group (n=7), PAH group (n=8), PAH+ RSD group(n=7). Pulmonary artery hypertension models were made by monocrotaline injection in PAH group and PAH+ RSD group, while bilateral renal artery sympathetic nerve were also ablated in PAH+ RSD group. Meanwhile, sham operation treatment were made in the control group and PAH group. The changes of blood pressure and cardiac indicies of ultrasound were observed before and after 8 weeks respectively. Then the left ventricular(LV) lateral strain, septal strain (IVS LS) and right ventricular(RV) strain were calculated. In the apical 4-chamber view, time from QRS onset to peak systolic strain in each the six segments of the LV and RV were measured and standard deviation of the time to peak longitudinal strain of six segments(LVTsl-6SD and RVTsl-6SD) were calculated. LV twist degree were obtained from LV rotation curve in basal and apical short-axis planes. Results After 8 weeks, there was no difference in the mean strain of LV lateral wall among the three groups, while the mean strain of RV lateral wall and septal were higher in PAH+ RSD group than the PAH group [(18.91±0.86)% % vs 16.34±1.36)%, P<0.001; (18.39±1.03)% vs (17.02±1.00)%, P<0.001, respectively]. Compared with PAH group, LVTsl-6SD and RVTsl-6SD of PAH+ RSD group decreased significantly [(25.45±3.59)ms vs (40.40±2.83)ms, P<0.001; (34.16±2.81)ms vs (51.98±3.64)ms, P<0.001, respectively]. The LV twist degree of PAH+ RSD group increased significantly[(10.47±0.73)° vs (8.46±1.06)°, P<0.001]. Conclusions RSD can reduce the influence of pulmonary artery hypertension on cardiac systolic function. Key words: Echocardiography; Hypertension, pulmonary; Renal sympathetic nerve; Catheter ablation; Ventricular function, left