Mitral annulus motion as determined by M-mode echocardiography in normal dogs and dogs with cardiac disease

Tissue motion annular displacement to assess the left ventricular systolic function in healthy cats

The tissue motion annular displacement (TMAD) measures the longitudinal displacement of the mitral annulus during systole, using speckle-tracking echocardiography (STE). The main objective was to determine the TMAD means in healthy cats, exploring the correlations with systolic surrogates. The influence of age, body surface area (BSA), heart rate, and systemic blood pressure on the indices was also analyzed. One hundred ninety-three healthy, client-owned cats participated in this prospective, cross-sectional observational study undergoing conventional and STE. Apical four-chamber (AP4) and two-chamber (AP2) images were recorded for offline calculations. Mean TMAD values were similar to mitral annulus plane systolic excursion (MAPSE), varying between 4 to 4.8 mm depending on the annulus and image used. No significant differences between age and BSA categories were detected, except for AP4 MP%, reduced in the heavier group. TMAD variables showed moderate correlation with longitudinal strain (LSt) and MAPSE, but not with fraction shortening (FS) and ejection fraction (EF). The median time required for the offline calculation was 12.2 s for AP4 and 11.8 s for AP2. The technique showed moderate inter and intraobserver variation, proving a reliable tool for assessing left ventricular longitudinal systolic function in cats.

CardiOvascular examination in awake Orangutans (Pongo pygmaeus pygmaeus): Low-stress Echocardiography including Speckle Tracking imaging (the COOLEST method)

Introduction

Cardiovascular diseases have been identified as a major cause of mortality and morbidity in Borneo orangutans (Pongo pygmaeus pygmaeus). Transthoracic echocardiography is usually performed under anesthesia in great apes, which may be stressful and increase risks of peri-anesthetic complications in case of cardiac alteration. The aim of the present pilot study was hence to develop a quick and non-stressful echocardiographic method (i.e., the COOLEST method) in awake Borneo orangutans (CardiOvascular examination in awake Orangutans: Low-stress Echocardiography including Speckle Tracking imaging) and assess the variability of corresponding variables.

Materials and methods

Four adult Borneo orangutans trained to present their chest to the trainers were involved. A total of 96 TTE examinations were performed on 4 different days by a trained observer examining each orangutan 6 times per day. Each examination included four two-dimensional views, with offline assessment of 28 variables (i.e., two-dimensional (n = 12), M-mode and anatomic M-mode (n = 6), Doppler (n = 7), and speckle tracking imaging (n = 3)), representing a total of 2,688 measurements. A general linear model was used to determine the within-day and between-day coefficients of variation.

Results

Mean±SD (minimum-maximum) images acquisition duration was 3.8±1.6 minutes (1.3–6.3). All within-day and between-day coefficients of variation but one (n = 55/56, 98%) were <15%, and most (51/56, 91%) were <10% including those of speckle tracking systolic strain variables (2.7% to 5.4%).

Discussion

Heart morphology as well as global and regional myocardial function can be assessed in awake orangutans with good to excellent repeatability and reproducibility.

Conclusions

This non-stressful method may be used for longitudinal cardiac follow-up in awake orangutans.

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

INTRODUCTION

Although 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.

ANIMALS

Ninety-four dogs with DMVD and 32 healthy dogs.

METHODS

Prospective 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.

RESULTS

The global TMAD_mm 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 TMAD_mm/kg (P = 0.017; r = -0.21) and global TMAD_mm/m² (P = 0.031; r = -0.19). Tissue motion annular displacement was fast to be performed and produced good repeatability in dogs with DMVD.

CONCLUSIONS

Global 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.

Echocardiographic assessment of dilated cardiomyopathy in dogs

Dilated cardiomyopathy (DCM) is a frequent cause of cardiac disability, congestive heart failure (CHF), and arrhythmic death in dogs. The etiology of DCM is usually idiopathic/genetic, but some causes of a DCM phenotype are reversible. The disease is classified into preclinical (occult) and clinical (overt) stages; the latter stems from heart failure with reduced ejection fraction. DCM is further characterized by clinical, electrocardiographic, circulating biomarker, and imaging abnormalities. The diagnosis of clinical DCM with CHF is straightforward; however, identification of the preclinical stage can be challenging. Echocardiography is central to the diagnosis of both stages and characterized by left ventricular (LV) systolic dysfunction with progressive chamber dilation and variable enlargements of the left atrium and right-sided chambers. Left ventricular dilation is defined by increased LV end-diastolic volumes, areas, and internal dimensions normalized to body size or indexed to the aorta. Systolic dysfunction is characterized by decreased LV ejection fraction, increased end-systolic volume, and reduced shortening across minor and longitudinal LV axes. Dyssynchrony can confound the interpretation of linear indices of systolic function. A comprehensive echocardiogram in DCM includes two-dimensional and M-mode studies, spectral and tissue Doppler imaging, and potentially three-dimensional echocardiography and myocardial strain imaging. Echocardiographic findings should be interpreted within the context of identifiable risks and comorbidities, physical diagnosis, complementary diagnostic testing, and limitations of current reference intervals. Ambiguous examinations should be repeated. Specific echocardiographic criteria for the diagnosis of DCM are proposed to encourage discussion and additional outcome and breed-specific echocardiographic studies of canine DCM.

An echocardiographic study of breed-specific reference ranges in healthy French Bulldogs

Echocardiography is a standard diagnostic tool for assessment of cardiac functions and cardiovascular diseases in dogs, however published echocardiographic measurements have varied widely based on dog breeds. The objective of this prospective reference interval study was to provide breed-specific echocardiographic values for healthy French Bulldogs. A total of 42 healthy French Bulldogs of both sexes (23 females and 19 males) were sampled. Furthermore, measurements for a control group (n = 16) were also conducted in four other dog breeds (Cocker Spaniel [n = 2], Cavalier King Charles Spaniel [n = 4], Terrier [n = 5], and Crossbreed [n = 5]). Standard M-mode, two-dimensional (2D), pulse wave (PW) Doppler, and tissue Doppler imaging (TDI) echocardiographic measurements were obtained from healthy French Bulldogs. The M-mode echocardiographic data obtained from French Bulldogs were compared to the data obtained from the control group. The left ventricular internal dimension at end-diastole (LVIDd; cm)/body surface area (BSA) (m² ) ratio for the study group was 3.35/0.53 = 6.32. Left ventricular measurements for French bulldogs and internal dimension at end-systole (21.23 ± 3.50 mm) and at end-diastole (33.50 ± 4.12 mm) were found to be significantly higher (P < .001) compared to control group values (left ventricular internal dimension at end-systole [LVIDs]; 17.46 ± 2.85 mm, LVIDd; 27.16 ± 4.20 mm, respectively). A significantly positive correlation in the French Bulldog group was noted between body weight and M-mode measurements (EPSS, IVSd, IVSs, LVIDd, LVIDs, and LVPWd). French bulldogs had a greater systolic and diastolic left ventricular volume than the control group. As a result, values reported in this study could be used as specific reference ranges in French Bulldogs.

Assessment of right ventricular systolic function by tissue motion annular displacement in healthy dogs

INTRODUCTION/OBJECTIVES

There are few parameters for assessment of right ventricular (RV) systolic function on echocardiographic examination. Morphofunctional studies are limited by the irregular shape of the RV. Recently, tissue motion annular displacement (TMAD), a technique that evaluates valve annulus displacement toward the cardiac apex, has shown a good correlation with left ventricular global longitudinal strain (GLS) in healthy dogs. Therefore, the aim of this study was to evaluate the longitudinal systolic function of the RV of healthy dogs using TMAD.

ANIMALS

A hundred healthy client-owned dogs.

MATERIALS AND METHODS

Cross-sectional study. Physical examination, electrocardiogram, blood pressure measurement, and echocardiography were recorded. The systolic function of the RV was evaluated by GLS free wall and TMAD. Data were compared with those derived from conventional echocardiography.

RESULTS

TMAD values varied according to body weight. There was a correlation of TMAD in millimeters with all indices of RV systolic function, including GLS free wall (R:-0.239; p:0.017). TMAD had a correlation with age and heart rate; whereas there was no relationship with sex and blood pressure. The coefficient of variation for the intraobserver evaluation was lower for the TMAD in millimeters (9.9%) compared with the GLS free wall (17.9%). In addition, the mean time to perform TMAD (8.1 s) was lower than that of the GLS free wall (37.7 s).

CONCLUSIONS

TMAD is a fast, reproducible, and promising method for assessing RV systolic function in healthy dogs. However, further studies are needed to understand the applicability of this technique in patients with heart disease.

Characterization of Doppler spectrum of hepatic veins and correlation with structural and functional variables of the right ventricle in healthy dogs

Background

Spectral Doppler assessment of hepatic veins may provide information on heart function.

Hypothesis/Objectives

To assess the normal pattern of hepatic venous flow using spectral Doppler ultrasound examination; to correlate this information with structural and functional variables of the right ventricle (RV), and to analyze the impact of age, sex, body weight quartiles, heart rate, cardiac rhythm, and systolic arterial pressure on the results in healthy dogs.

Animals

Sixty‐five healthy dogs.

Methods

Cross‐sectional observational study. The direction and maximum velocity of each of the 4 possible components of venous flow were determined from pulsed‐wave Doppler examination of the hepatic veins. In addition, structural and functional parameters (TAPSE, longitudinal strain, FAC%, S′, E_t/A_t, and E′_t/ A′_t) of the RV were evaluated.

Results

The same phase patterns for different waves were seen in all animals: A and V were retrograde waves, and S and D were anterograde waves. The velocity of the spectral waves increased with body weight (P < .05) and could be correlated with functional indices of the RV. A significant difference was found when comparing morphometric indices with body weight quartiles (P < .05). In addition, intra‐and inter‐observer assessments showed low variability. The mean duration of the examinations was 5.2 minutes.

Conclusions and Clinical Importance

Hepatic spectral Doppler findings can be correlated with systolic and diastolic indices of the RV and vary with body weight.

Diagnostic methods for the canine idiopathic dilated cardiomyopathy: A narrative evidence-based rapid review

Idiopathic dilated cardiomyopathy (DCM) is an important etiology of mortality and morbidity in dogs and its diagnosis relies on systolic dysfunction, chambers dilation, electrical instability and congestion. During the last decades veterinary cardiologists have been joining efforts to obtain diagnostic resources to correctly identify canine DCM in the preclinical stage. Unfortunately, most diagnostic resources have been used with the support of research with weak evidence, without high quality methodologies such as systematic reviews or meta-analysis. Therefore, the support of evidence-based medicine is tailored by empiricism and diagnostic criteria lose'out the ability to properly classify dogs suffering DCM. The presentation of the evidence in medicine is established by multiple sources and the most reliable source has been the presentation of evidence-based medicine from systematic reviews and meta-analysis. Rapid reviews can be interpreted as a pragmatic approach to systematic reviews and although a rapid review follows most of the critical steps of a systematic review to provide timely evidence, some components of a systematic review process are either simplified or omitted. The objective of this narrative evidence-based rapid review is twofold. First: To recognize and to stratify the level of evidence offered by rigorous selected papers about the diagnosis of DCM. Second: To classify the degree of clinical recommendation of the diagnostic resources available.

Echocardiographic reference ranges for sedated healthy peccaries ( Tayassu tajacu, Linnaeus , 1758 )

ABSTRACT Peccaries are wild mammals belonging to the Tayassu genus that are found almost everywhere in the Americas and have demonstrated great potential as an experimental model for scientific investigations. Twelve healthy adult animals were sedated to perform echocardiographic examinations in B, M and Doppler mode. The variables that exhibited statistically significant correlation coefficients with weight were LVFWd, LVIDd, LVIDs, E wave, A’RV, MAM, and TAPSE. The HR exhibited a negative relationship with the IVRT. The LA variable showed a positive correlation with the AO. The MAM exhibited correlations with the LVIDd and LVIDs. The TAPSE showed positive correlations with the E’RV and A’RV. The present study provides the first reference values for echocardiographic measurements in B, M and Doppler modes from peccaries anesthetized with ketamine and midazolam. Echocardiography was easy to perform in collared peccaries, and the collected data revealed values that can aid in their clinical management and conservation.

Echocardiographic parameters in dogs treated with acepromazine and fentanyl

ABSTRACT Considering that the use of tranquillizers could optimize the performance of the echocardiogram, this study aimed to evaluate the effect of protocols with acepromazine and fentanyl on the echocardiographic parameters of healthy dogs, besides their effect in systolic blood pressure (SBP), respiratory rate (RR), heart rate (HR), time spent for examination and sedation scale. Ten adult dogs were submitted to different tranquilizing protocols 20 minutes before the echocardiographic examination, totalling five treatments for each pair, performed at seven-day intervals between evaluations. The treatments were CT (control treatment), IAT (intramuscular acepromazine), OAT (oral acepromazine), FT (fentanyl) and AFT (acepromazine associated with fentanyl). In addition to the echocardiographic evaluation, SBP, degree of reassurance, duration of the exam, HR and RR in the different protocols were evaluated. There was a significant decrease of SBP in OAT. There was a significant reduction in left ventricular diameter during systole and diastole and mitral annular movement in IAT, OAT and AFT, compared with CT. There was a decrease in tricuspid annular plane systolic excursion and increase in mitral E/mitral A ratio in IAT and OAT when compared with CT. All the tranquillizer protocols studied were found to significantly reduce HR, that facilitated the echocardiographic examination.

Effect of exercise on cardiovascular parameters in search and rescue-trained dogs

ABSTRACT Physical activity alters the cardiovascular system of dogs, depending on the exercise characteristics and the animal’s physical conditioning. Little is known about the cardiovascular changes in rescue-trained dogs. This study evaluated the cardiovascular responses to a search and rescue exercise session to differentiate these alterations from cases of exhaustion or some possible pathology. Nine healthy rescue-trained dogs that trained for at least one year were used. Seven German Shepherds and two Belgian Shepherd Malinois were evaluated twice, immediately before exercise (M0) and immediately after a 20-minute training (M1). Electrocardiographic, echocardiographic, and systemic blood pressure (SBP) measurements were performed at each evaluation. Heart rate was evaluated in three moments, M0, M1 and five minutes after the end of the physical activity (M2). The results indicated that training increased oxygen demand and significantly increased cardiac output, left ventricular volume in diastole and aortic artery diameter, and the contraction force with the increased mitral annular motion without impairing systolic and diastolic cardiac functions. Heart rate values immediately and five minutes after exercise were similar to baseline values. Training did not alter SBP and the electrocardiographic parameters. The present study indicated good cardiac performance to the physical effort of rescue-trained dogs and reduced the chances of poor performance and the occurrence of sudden death caused by exercise in response to the pattern of activity performed.

Parâmetros ecocardiográficos em cães saudáveis tratados com acepromazina, meperidina e sua associação

RESUMO Objetivou-se avaliar os efeitos da tranquilização com meperidina, acepromazina e de sua associação sobre os parâmetros ecocardiográficos em cães. Foram utilizados 12 cães adultos, da raça Rottweiler, submetidos ao exame ecocardiográfico sem utilização de sedação (controle - TC) e a três protocolos de tratamento, utilizando-se meperidina (TM), acepromazina (TA) e a associação dos medicamentos (TMA). As variáveis foram analisadas pelo teste de Tukey (P<0,05). Observou-se que as médias obtidas na onda A do fluxo mitral em TA e TMA diminuíram significativamente com relação ao TM, que não diferiu do TC. Houve uma diminuição significativa no valor de movimento anular mitral (MAM) e excursão sistólica do plano anular tricúspide (ESPAT) no TA. Não houve diferença significativa para os valores de fração de encurtamento (FE) entre TA e os demais tratamentos. Entretanto, observou-se que 57,3% dos cães apresentaram valores de FE abaixo da normalidade. As alterações encontradas podem ser decorrentes dos efeitos hipotensores da acepromazina utilizada de forma isolada. Conclui-se que a meperidina ou sua associação com acepromazina não alteram os parâmetros ecocardiográficos em cães saudáveis e que a acepromazina, utilizada isoladamente, causa alteração nos parâmetros de função sistólica dos cães, não sendo recomendada para a contenção química dos cães submetidos ao ecocardiograma, o que poderia levar à má interpretação do exame.

Advances in echocardiography

Echocardiography is an exceptionally useful technique for diagnosing cardiovascular disease in small animals. It is noninvasive and provides a wealth of data concerning cardiac morphology and function. For many patients, echocardiography is the definitive diagnostic tool. A well-performed study coalesces the findings of the physical examination, electrocardiogram, and radiographs into a clearly defined diagnosis on which treatment decisions can be based. More so than other diagnostic techniques, echocardiography is highly operator dependent and relies on the proper acquisition and interpretation of results by an examiner who is familiar with the principles, capabilities, and limitations of ultrasound imaging. This article reviews the basics of echocardiography, measurement of cardiac dimensions, and assessment of cardiac function. Within these sections, emerging technologies that expand the capabilities of the echocardiographic examination are introduced.

Assessment of repeatability, reproducibility, and effect of anesthesia on determination of radial and longitudinal left ventricular velocities via tissue Doppler imaging in dogs

OBJECTIVE

To determine left ventricular free wall (LVFW) motions and assess their intra- and interday variability via tissue Doppler imaging (TDI) in healthy awake and anesthetized dogs.

ANIMALS

6 healthy adult Beagles.

PROCEDURE

n the first part of the study, 72 TDI examinations (36 radial and 36 longitudinal) were performed by the same observer on 4 days during a 2-week period in all dogs. In the second part, 3 dogs were anesthetized with isoflurane and vecuronium. Two measurements of each TDI parameter were made on 2 consecutive cardiac cycles when ventilation was transiently stopped. The TDI parameters included maximal systolic, early, and late diastolic LVFW velocities.

RESULTS

The LVFW velocities were significantly higher in the endocardial than in the epicardial layers and also significantly higher in the basal than in the mid-segments in systole, late diastole, and early diastole. The intraday coefficients of variation (CVs) for systole were 16.4% and 22%, and the interday CV values were 11.2% and 16.4% in the endocardial and epicardial layers, respectively. Isoflurane anesthesia significantly improved the intraday CV but induced a decrease in LVFW velocities, except late diastolic in endocardial layers and early diastolic in epicardial layers.

CONCLUSIONS AND CLINICAL RELEVANCE

Left ventricular motion can be adequately quantified in dogs and can provide new noninvasive indices of myocardial function. General anesthesia improved repeatability of the procedure but cannot be recommended because it induces a decrease in myocardial velocities.