Ventricular Systolic Function In Dogs Research Articles

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.

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.

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.

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.

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.

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

Long-term therapy with Bendavia (MTP-131), a novel mitochondria-targeting peptide, improves left ventricular systolic function in dogs with chronic heart failure

Background: Mitochondria (MITO) of the failing heart manifest structural and functional abnormalities evidenced by hyperplasia, reduced organelle size and diminished respiration that lead to a defect in ATP synthesis. Bendavia (MTP-131), a novel, first in class, MITO-targeting peptide, improves the efficiency of mitochondria electron transfer chain and enhances ATP synthesis in multiple organs including heart, kidney and skeletal muscle. The present study examined the effects of long-term therapy with Bendavia on LV systolic function and ATP synthesis in dogs with chronic heart failure (HF) (LV ejection fraction, EF∼30%). Methods: Fourteen dogs with coronary microembolization-induced HF were randomized to 3 months therapy with subcutaneous injections of Bendavia (0.5 mg/kg once daily, n=7) or saline (Control, n=7). LV end-diastolic (EDV) and end-systolic (ESV) volumes, EF, heart rate (HR), mean aortic pressure (AP), LV end-diastolic pressure (EDP) and peak LV +dP/dt were measured before (PRE) and after 3 months of therapy (POST). Treatment effect Δ, within each group, was calculated as the difference between PRE and POST. MITO ATP synthesis and ATP/ADP ratio were measured in isolated LV cardiomyocytes obtained at the end of 3 months of therapy using the bioluminescent ApoSENSORTM ATP/ADP assay kit. Results: Bendavia had no effect on HR or mAP. Compared to Control, Bendavia decreased EDV, ESV and EDP, increased EF and peak LV +dP/dt and increased ATP synthesis and ratio of ATP/ADP (Table). View this table: Indexes of LV function and ATP Synthesis Conclusions: In HF dogs, long-term monotherapy with Bendavia improves LV systolic function without increasing HR or decreasing mAP. Bendavia increased ATP synthesis; a likely mediator of improved LV function.

Assessment of longitudinal tissue Doppler imaging of the left ventricular septum and free wall as an indicator of left ventricular systolic function in dogs

To evaluate tissue Doppler imaging (TDI) of the left ventricular (LV) free wall (FW) and ventricular septum (VS) as an indicator of LV systolic function in dogs. 7 healthy Beagles. Doses of dobutamine (5 and 10 microg/kg/min) and esmolol (50 and 100 microg/kg/min) were infused into the LV of each dog. With each dose, heart rate; myocardial performance index (MPI); transmitral inflow and ejection time (determined via pulsed-wave Doppler [PWD] echocardiography); and FW and VS velocities of the mitral valve annulus (determined via TDI during systole [S'], early diastole [E'], and late diastole [A']) were assessed. With each dose, dobutamine significantly increased heart rate and the first derivatives of LV pressure (+dP/dt and -dP/dt), whereas esmolol significantly decreased the +dP/dt and -dP/dt values, compared with baseline. Esmolol (100 microg/kg/min) significantly decreased the VS-TDI-derived S' velocity and FW-TDI-derived E' velocity; dobutamine significantly increased transmitral inflow and TDI velocities. Regression coefficient between VS-TDI-derived S' velocity and +dP/dt was higher than that between FW-TDI-derived S' velocity and +dP/dt. Compared with baseline, the PWD- and VS-TDI-derived MPI were significantly decreased by dobutamine and significantly increased by esmolol at each dose. Values of FW-TDI-derived MPI were higher than values derived via the other techniques. Correlation between +dP/dt and VS-TDI-derived MPI was greater than that between +dP/dt and FW-TDI- or PWD-derived MPI. In healthy dogs, the VS-TDI-derived S' velocity and MPI appear to be reliable assessments for evaluating LV systolic function.

509 Therapy with Vagus nerve electrical stimulation combined with beta-blockade improves left ventricular systolic function in dogs with heart failure beyond that seen with beta-blockade alone

509 Therapy with Vagus nerve electrical stimulation combined with beta-blockade improves left ventricular systolic function in dogs with heart failure beyond that seen with beta-blockade alone

Intravenous Istaroxime Improves Left Ventricular Systolic Function in Dogs with Advanced Heart Failure without Increasing Myocardial Oxygen Consumption

Intravenous Istaroxime Improves Left Ventricular Systolic Function in Dogs with Advanced Heart Failure without Increasing Myocardial Oxygen Consumption

Plication of the free wall of the left ventricle in dogs with doxorubicin-induced cardiomyopathy

To evaluate plication of the free wall of the left ventricle, which reduces the left ventricular area and volume, as a method to improve the left ventricular systolic function without cardiopulmonary bypass. 8 mixed-breed adult dogs. Dilated cardiomyopathy (DCM) was induced in each dog by administration of doxorubicin (30 mg/m2, i.v., q 21 d for 168 days). Two dogs died during induction of cardiomyopathy. Plication surgery was performed in 4 dogs. Two dogs did not ondergo to surgery (control group). Values for cardiac output (CO), 2-dimensional and M-mode echocardiography, arterial blood pressure, electrocardiography, blood cell counts, and serum biochemical analyses were recorded after induction of DCM (baseline) and 1, 2, 7, 15, 21, 30, 60, 90, 120, 150, and 180 days after plication surgery. Ambulatory ECG (Holter) recordings were conducted for 24 hours on the day of surgery. 1 dog died after plication surgery. The remaining dogs undergoing ventricular plication had a significant improvement in CO, ejection fraction, and fractional shortening and reductions of left ventricular area and volume after surgery. Electrocardiographic and Holter recordings revealed premature ventricular complexes, which resolved without treatment during the first week after surgery. Clinical condition of the control dogs declined, and these 2 dogs died approximately 40 days after induction of cardiomyopathy. Plication of the free wall of the left ventricle improved left ventricular systolic function in dogs with doxorubicin-induced cardiomyopathy. Additional studies are needed to evaluate its application in dogs with naturally developing DCM.

Estudo da função ventricular na técnica de plicatura da parede livre do ventrículo esquerdo em cães

OBJETIVO: Avaliar os efeitos da tecnica na funcao ventricular esquerda em caes higidos e com cardiomiopatia dilatada induzida pela doxorrubicina. METODO: De 13 caes, oito receberam doxorrubicina ate que a fracao de encurtamento (FE) fosse menor que 20%. Destes, quatro animais e os cinco nao induzidos foram submetidos a plicatura da parede livre do ventriculo esquerdo (PPLVE). Os demais caes nao foram operados. Foram avaliados debito cardiaco (DC), pressao arterial, exame fisico, eletrocardiografia, sistema Holter e ecocardiografia, por 180 dias. RESULTADOS: Houve reducao do volume ventricular esquerdo. Os caes induzidos melhoraram apos a operacao e a fracao de ejecao (FEj) retornou aos valores normais para a especie. O DC e a FE aumentaram apos a operacao. Um cao foi a obito. Nos caes nao operados, a FE diminuiu e foram a obito em torno de 40 dias apos a inducao; nos caes nao induzidos, esta nao se alterou. Houve extra-sistoles ventriculares, que se resolveram espontaneamente. CONCLUSOES: A PPLVE sem circulacao extracorporea reduz o volume ventricular esquerdo e melhora a funcao cardiaca dos caes com cardiomiopatia dilatada induzida pela doxorrubicina, demonstrando baixa morbidade e mortalidade tardia.

Pressure studies after inactivation of the major portion of the canine right ventricle.

Pressure studies after inactivation of the major portion of the canine right ventricle.