Intra-aortic band impairs transapical device implantation in a pig: a case report.

BACKGROUND: Anatomic anomalies in the ascending aorta may impair the implantation and testing of cardiovascular devices in humans and animal models. CASE PRESENTATION: We present the rare case of an intra-aortic band in a German Landrace pig. During terminal animal testing, the band hindered the implantation of a left ventricular assist device (LVAD) with transventricular outflow graft across the aortic valve. After lower partial sternotomy, epicardial echocardiography displayed an intraluminal echogenic structure at the sinotubular junction causing unspecific flow turbulences. Under cardiopulmonary bypass, coring of the left ventricular apex was performed. Due to strong resistance in the proximal aorta, accurate positioning of the transventricular LVAD outflow graft was impossible. After euthanasia, necropsy revealed a fibrous band located at the sinotubular junction, dividing the lumen of the ascending aorta. CONCLUSIONS: The occurrence of an intra-aortic band represents an extremely rare case of a most likely congenital anomaly. Awareness of such anomalies is important for planning and performing animal testing. Perioperative echocardiography may help to either remove such anomalies or allow discontinuing the procedure prior to device implantation.

Aortic valve insufficiency caused by a hypoplastic aortic valve in a calf.

A 1-month-old crossbred calf was referred for examination due to marked systolic heart murmurs and poor growth. The heart murmur was most audible on the right side of the cranial thorax. Cardiomegaly was evident on chest radiography, and echocardiography demonstrated aortic regurgitation and decreased fractional shortening. Cardiomegaly, aortic root dilation and cardiac displacement were confirmed by computed tomography. At necropsy, the heart was enlarged, and all three aortic valve leaflets were irregularly shaped. In calves with chronic aortic insufficiency, remodeling displacement of the heart and aorta causes changes in the location and timing of heart murmurs. Therefore, aortic insufficiency cannot be ruled out when a systolic heart murmur can be observed in the right chest wall.

Assessment of left ventricular function in horses with aortic regurgitation by 2D speckle tracking.

BACKGROUND: Aortic regurgitation (AR) may lead to left ventricular (LV) dilatation, cardiac arrhythmias and heart failure. Close follow-up of horses with AR is therefore paramount to detect onset of cardiac decompensation. The aim of this study was to examine whether two-dimensional speckle tracking (2DST) can be used to detect altered myocardial function in horses with chronic AR compared to control horses. Speckle tracking was performed on short axis and long axis images of the LV in 29 healthy Warmblood horses and 57 Warmblood horses with AR. Radial, circumferential and longitudinal strain, strain rate and displacement were measured for each segment separately and the average was calculated over all segments. Data generated from the apical segments were not included in the analysis. RESULTS: Radial (SR) and circumferential (SC) strain were significantly higher in horses with moderate AR (average SR 75.5 ± 24.3%, SC 19.3 ± 3.2%) but not in horses with severe AR (SR 65.5 ± 26.2%, SC 16.3 ± 3.5%), compared to control horses (SR 54.5 ± 18.0%, SC 16.8 ± 3.0%). Longitudinal strain did not show significant differences, but longitudinal displacement (DL) was larger in horses with moderate (average DL 29.5 ± 4.1 cm) and severe AR (DL 32.4 ± 6.1 cm) compared to control horses (DL 25.7 ± 4.0 cm), especially in the interventricular septum. Diastolic longitudinal strain rate was lower in early diastole in horses with severe AR (0.93 ± 0.18/s) compared to controls (1.13 ± 0.13/s). CONCLUSIONS: 2DST is able to detect altered myocardial motion in horses with AR, which showed significantly higher radial and circumferential strain. Further research is needed to determine whether these findings contribute to a more accurate diagnosis and prognosis in clinical cases.

Diagnostic value of noninvasive pulse pressure measurements in Warmblood horses with aortic regurgitation.

BACKGROUND: Noninvasive blood pressures (NIBP) and pulse pressures (PP) have not been published in horses with aortic and mitral regurgitation (AR or MR). OBJECTIVES: To investigate NIBP and PP in healthy Warmblood horses and horses with AR and MR and propose PP cutoffs to identify and stage AR severity. ANIMALS: Seventy-three Warmblood horses (healthy, 10; AR, 31; MR, 32). METHODS: Retrospective study. All horses had NIBP and an echocardiogram recorded. Cases were categorized based on severity of regurgitation. Pulse pressures were compared among healthy, MR, and AR groups and among AR severity groups. Cutoffs were determined by receiver operating characteristic curve analyses. RESULTS: Horses with AR had higher PP than horses with MR (mean difference [95% confidence interval (CI)], +17 [9-26] mm Hg, P < .001) and controls (+17 [5-30] mm Hg; P =.004). Horses with severe AR had higher PP compared those with mild (+38 [20-54] mm Hg; P < 0.001) and moderate AR (+33 [18-47] mm Hg; P < .001). The PP cutoffs to distinguish AR from MR and controls were 38 mm Hg (sensitivity [Sn], 100%; specificity [Sp], 19%) for maximal Sn and 61 mm Hg (Sn, 43%; Sp, 100%) for maximal Sp. The PP cutoffs to distinguish severe AR from mild and moderate AR were 57 mm Hg (Sn, 100%; Sp, 70%) for maximal Sn and 77 mm Hg (Sn, 75%; Sp, 100%) for maximal Sp. CONCLUSIONS AND CLINICAL IMPORTANCE: Horses with AR have increased PP. Noninvasive PP measurements interpreted with provided cutoffs may aid clinicians in diagnosing and staging severity of AR in horses.

Preliminary investigation of orally administered benazepril in horses with left-sided valvular regurgitation.

BACKGROUND: Despite the paucity of data available, orally administered angiotensin-converting enzyme (ACE) inhibitors are empirically used in horses with valvular regurgitation. OBJECTIVE: Evaluate the echocardiographic and hormonal changes in response to oral benazepril in horses with left-sided valvular regurgitation. STUDY DESIGN: Prospective, randomised double-blind, placebo-controlled trial. METHODS: Horses with mitral valve (MR) and/or aortic valve regurgitation (AR) received oral benazepril (n = 6) at a dosage of 1 mg/kg q 12 h or a placebo (n = 5) for 28 days. Echocardiography was performed before drug administration and after 28 days of treatment. Plasma renin activity, serum ACE activity, angiotensin II concentration, aldosterone concentration and biochemical variables were measured before drug administration and after 7 and 28 days of treatment. RESULTS: Relative to baseline, horses treated with benazepril had statistically significant reduction in left ventricular internal diameter in systole (mean difference between groups = -0.97 cm; 95% CI = -1.5 to -0.43 cm), aortic sinus diameter (-0.31 cm; -0.54 to -0.07 cm), and percentage of the aortic annulus diameter occupied by the base of the AR jet (-17.05%; -31.17 to -2.93%) compared with horses receiving a placebo. In addition, horses treated with benazepril had a significantly greater increase in cardiac output (11.95 L/min; 1.17-22.73 L/min) and fractional shortening (7.59%; 3.3-11.88%) compared with horses receiving a placebo. Despite profound serum ACE inhibition, renin activity and concentrations of angiotensin II and aldosterone were not significantly different between treatment groups or among time points. MAIN LIMITATIONS: Very small sample size and short treatment period. CONCLUSIONS: Treatment with oral benazepril resulted in statistically significant echocardiographic changes that might indicate reduced cardiac afterload in horses with left-sided valvular regurgitation. Additional studies with a larger sample size will be necessary to determine if administration of benazepril is beneficial in horses with valvular regurgitation. The Summary is available in Spanish - see Supporting Information.

Assessing aortic regurgitation severity from 2D, M-mode and pulsed wave Doppler echocardiographic measurements in horses.

Aortic regurgitation (AR) in horses can lead to left ventricular (LV) eccentric hypertrophy, ventricular arrhythmia and heart failure. Objective quantification of the severity of regurgitation is difficult. The aim of this study was to evaluate dimensional measurements, systolic time intervals and blood flow velocities, acquired by standard 2D, M-mode and pulsed wave Doppler echocardiography, for quantification of AR. Echocardiography was performed in 32 healthy horses and 35 horses with AR that were subdivided in three groups (mild, moderate or severe AR). From the recorded images LV, left atrial and aortic dimensions, systolic time intervals and aortic blood flow velocities were measured. Diastolic run-off in the aorta (AoDiastDecr) was calculated as the difference in aortic diameter between early diastole and late diastole. Stroke volume (SV) was calculated from pulsed wave Doppler measurements, by the bullet method (SVbullet) and by the area-length method. Pre-ejection period (PEP) and ejection time (LVET) were determined from the M-mode images. Horses with AR showed enlargement of the LV, left atrium and aorta compared to the control group. The SV, the AoDiastDecr and the rate of AoDiastDecr were significantly larger than controls. PEP decreased significantly in horses with AR, whereas LVET did not change. PEP and the newly defined variable AoDiastDecr proved to be easy to measure parameters that provided a good indication of AR severity. There was increased SV in horses with AR using all three methods, but SVbullet was superior for the detection of increased AR severity.

Recommendations for management of equine athletes with cardiovascular abnormalities.

Murmurs and arrhythmias are commonly detected in equine athletes. Assessing the relevance of these cardiovascular abnormalities in the performance horse can be challenging. Determining the impact of a cardiovascular disorder on performance, life expectancy, horse and rider or driver safety relative to the owner's future expectations is paramount. A comprehensive assessment of the cardiovascular abnormality detected is essential to determine its severity and achieve these aims. This consensus statement presents a general approach to the assessment of cardiovascular abnormalities, followed by a discussion of the common murmurs and arrhythmias. The description, diagnosis, evaluation, and prognosis are considered for each cardiovascular abnormality. The recommendations presented herein are based on available literature and a consensus of the panelists. While the majority of horses with cardiovascular abnormalities have a useful performance life, periodic reexaminations are indicated for those with clinically relevant cardiovascular disease. Horses with pulmonary hypertension, CHF, or complex ventricular arrhythmias should not be ridden or driven.

Familial subvalvular aortic stenosis in golden retrievers: inheritance and echocardiographic findings.

OBJECTIVES: To describe the echocardiographic findings and pedigree analysis of golden retrievers with subvalvular aortic stenosis. METHODS: Seventy-three golden retrievers were evaluated by auscultation and echocardiography. A subcostal continuous-wave Doppler aortic velocity ê2·5 m/s and presence of a left basilar systolic ejection murmur were required for diagnosis of subvalvular aortic stenosis. Three echocardiographic characteristics were recorded: evidence of aortic insufficiency, subvalvular ridge or left ventricular hypertrophy. A disease status score was calculated by totalling the number of echocardiographic -characteristics per subject. RESULTS: Thirty-two of 73 dogs were affected and their aortic velocities were as follows: range 2·5 to 6·8 m/s, median 3·4 m/s and standard deviation 1·2 m/s. Echocardiographic characteristics of 32 affected dogs were distributed as follows: left ventricular hypertrophy 12 of 32, aortic insufficiency 20 of 32 and subvalvular ridge 20 of 32. Disease status score ranged from 0 to 3 with a median of 2. There was a statistically significant correlation between aortic velocity and disease status score (r=0·644, P<0·0001). Subvalvular aortic stenosis was observed in multiple generations of several families and appears familial. CLINICAL SIGNIFICANCE: Subvalvular aortic stenosis in the golden retriever is familial. Severity of stenosis correlates well with cumulative presence of echocardiographic characteristics (left ventricular hypertrophy, subvalvular ridge and aortic insufficiency).

[Aortic insufficiency: diagnosis and haemodynamics, incidence in an unselected group of Irish Wolfhounds]. / Die Aortenklappeninsuffizienz: Diagnose und Hämodynamik, Vorkommen in einer nichtselektierten Gruppe Irischer Wolfshunde.

Common causes of acute and chronic aortic regurgitation are discussed. The main diagnostic tool is focused on echocardiographic evaluation and determination of the severity. A group of 50 Irish Wolfhounds underwent a clinical, electrocardiographic and echocardiographic examination. In 40 dogs an abnormal finding due to heart disease could be detected, which comprised an aortic insufficiency in 23 of the dogs. Only in one case was a severe degree of aortic regurgitation found, while in nine cases a moderate and in 13 dogs a mild degree was found. The occurrence of additional findings as atrial and chamber enlargement, mitral valve insufficiency, and atrial fibrillation correlated with the severity of the aortic insufficiency.

Ventricular septal defect with aortic valve insufficiency in a New Zealand White rabbit.

A heart murmur was detected in a 10 mo old, female New Zealand White rabbit. Auscultation revealed cardiac murmurs both at the left and right hemithorax. Phonocardiography confirmed the systolic-diastolic nature of the left-sided and the systolic character of the right-sided murmur. Electrocardiography showed normal sinus rhythm; tall R waves and large T waves in lead II; and deep S waves in leads II, III, and aVF. Thoracic radiography demonstrated generalized cardiomegaly with prominent pulmonary vasculature. Echocardiography revealed a perimembraneous ventricular septal defect with aortic insufficiency. Signs of biventricular volume overload, relative pulmonic stenosis, and pulmonary valve insufficiency were also seen as consequences of the defect. Necropsy demonstrated a ventricular septal defect just below the aortic valve, a dilated pulmonary trunk, dilated and hypertrophied ventricles, dilated atria, and rightward displacement of the aortic root. Cardiac histopathology showed ventricular cardiomyocyte degeneration (swelling and hypereosinophilia of the cytoplasm with a loss of cross striation, and nuclear hyperchromasia), cartilaginous metaplasia of the aorta, and subendocardial fibrosis of the right ventricular flow tract.

The prevalence of cardiac murmurs among standardbred racehorses presented with poor performance.

Seven hundreds fifty-two Standardbreds, with poor performance, underwent a thorough diagnostic protocol. In 157 out of 233 horses, with cardiac murmurs, echocardiography and color flow Doppler (CFD) mapping were performed. Murmur of tricuspid valve regurgitation was identified in 185 horses, while murmurs of mitral (23), aortic (9) and pulmonary (3) valve regurgitations were detected less frequently. Functional systolic, functional pre-systolic, and functional early diastolic murmurs were identified in 10, 11 and 2 horses. Two-dimensional and M-mode echocardiography showed no abnormality in 145 horses and by CFD the presence of one or more jets of valve regurgitation were observed in 149 patients. The results obtained suggest that cardiac murmurs are a common finding in Standardbreds presented with poor performance.

Effect of left-sided valvular regurgitation on mortality and causes of death among a population of middle-aged and older horses.

The effect of left-sided valvular regurgitation (LSVR) on the mortality of middle-aged and older horses was investigated in a prospective cohort study involving 19 yards and 1153 horses. The horses were examined to determine whether they had a cardiac murmur and its type, and their age, sex, breed type and occupation were recorded. They were followed up at intervals of two years by postal questionnaire, and after four years information on 773 horses was available. There was no significant difference in the mortality of the horses with and without LSVR, but small horses had a significantly higher risk of having LSVR than small ponies (odds ratio [OR] 2.33), and older horses were slightly more likely to have LSVR than young horses (OR 1.07). Twenty-nine per cent of the deaths reported by the owners were due to orthopaedic problems, 23.3 per cent to gastrointestinal problems, and only 7.9 per cent to cardiovascular problems. Orthopaedic problems were the main cause of death in the horses, and gastrointestinal problems were the main cause of death in the ponies.

Quadricuspid aortic valve and associated abnormalities in the dog: report of six cases.

OBJECTIVES: To describe the clinical and echocardiographic findings in dogs with quadricuspid aortic valve (QAV). BACKGROUND: QAV is a rare canine congenital heart disease which has been reported only three times in the young dog. ANIMALS, MATERIALS AND METHODS: Six dogs (0.3- to 13-year-old) with QAV diagnosed by two-dimensional echocardiography were retrospectively evaluated. Medical records, echocardiograms, and follow-ups were reviewed. RESULTS: According to aortic cusp morphology, QAV was classified as type A (n=1), type B (n=4) or type C (n=1). QAV was associated with at least one other heart disease in all of the dogs including, ventricular septal defect (n=1), enlarged left coronary ostium (n=4), degenerative mitral valve disease (MVD, n=1) and patent ductus arteriosus (PDA, n=3). Mild to moderate aortic regurgitation was also detected in all dogs by continuous-wave and color-flow Doppler echocardiography. QAV was diagnosed in four asymptomatic dogs referred for evaluation of a heart murmur. The remaining two dogs had QAV and PDA with evidence of mild exercise intolerance and moderately retarded growth. The PDA was surgically corrected in both dogs and at the time of writing, 1-2.5 years after the initial diagnosis, none of the six animals shows evidence of clinical signs. CONCLUSION: QAV is a cause of aortic insufficiency. It may incidentally be found by two-dimensional echocardiography in dogs of various ages in association with other congenital or acquired cardiac abnormalities.

Plasma atrial natriuretic peptide concentration in warmblood horses with heart valve regurgitations.

OBJECTIVES: This study measured plasma atrial natriuretic peptide (ANP) concentration in horses with heart valve regurgitations (HVR) with and without atrial and ventricular dilatation. BACKGROUND: In humans and small animals, plasma ANP concentration is increased in heart disease and correlates with the severity of clinical signs and heart enlargement. ANIMALS, MATERIALS AND METHODS: Ten healthy horses (control) and 36 horses with HVR were evaluated by auscultation, electrocardiography, echocardiography, and determination of plasma ANP. RESULTS: Control horses demonstrated mean plasma ANP concentration of 21+/-5.4 pg/mL. Of the 36 horses with HVR, 17 horses possessed normal echocardiographic heart size (group 1), 10 horses had a left atrial dilatation (group 2) and 9 horses had both left atrial and ventricular dilatation (group 3). Mean plasma ANP concentration of groups 1, 2 and 3 was 20.1+/-5.6 pg/mL, 22.9+/-11.0 pg/mL and 27.6+/-17.4 pg/mL, respectively. The plasma ANP concentrations of HVR and control horses were not significantly different. The highest ANP concentrations were observed in horses with atrial and ventricular dilatation. No correlation between left atrial or ventricular size, weight, or sex and the plasma ANP concentration was found. CONCLUSIONS: No significant differences in plasma ANP concentration was observed between groups. Further study, especially in horses with clinical signs of heart failure is needed.

Surgical correction of ventricular septal defect with aortic regurgitation in a dog.

An 8-month-old entire Miniature Dachshund, weighing 4.2 kg, was presented for examination following delvelopment of a cough. Ventricular septal defect had been diagnosed tentatively in its infancy on the basis of a cardiac murmur detected by auscultation and echocardiography. Echocardiography using a B mode right parasternal long-axis view showed a defect at the atrioventricular junction and a thickened cusp of the aortic valve prolapsing into the defect. Colour-flow Doppler showed shunt blood flow across the defect at the level of the atrioventricular junction, from left to right. The sinus of Valsalva was dilated, with turbulent blood flow. Aortic regurgitation was also observed. Cardiac catheterisation studies confirmed the diagnosis of a supracristal ventricular septal defect with aortic regurgitation. Despite medication with digoxin, enalapril and aminophylin, started from the first admission, left ventricular internal dimensions gradually increased, and fractional shortening of the left ventricle gradually decreased. Surgery, with the aid of extracorporeal circulation, to close the ventricular septal defect, was performed 1 year after the initial examination. The aortic valve was left untreated. Postoperatively, the systolic murmur disappeared. Shunt flow from the left to the right ventricle was no longer observed on echocardiography, however there was still a small amount of aortic regurgitation during diastole visualised with colour-flow Doppler echocardiography. The prolapse of the cusp of the aortic valve on B-mode echocardiography was no longer observed and thickening of the cusp had not progressed. Left ventricular function measurement using M mode echocardiography showed a reduced left ventricular volume overload with reduced left ventricular internal dimensions and increased fractional shortening. The cough was relieved and no follow-up medication was scheduled. Early surgical closure of the ventricular septal defect improved the patient's condition and controlled prolapse and thickening of the aortic valve.

Associations between exercise-induced pulmonary haemorrhage, right ventricular dimensions and atrioventricular valve regurgitation in conditioned national hunt racehorses.

REASONS FOR PERFORMING STUDY: Exercise-induced pulmonary haemorrhage (EIPH) and tricuspid (TR) and mitral valve regurgitation (MR) are conditions with high prevalence in conditioned Thoroughbreds. Stress failure of pulmonary capillaries, leading to EIPH, is most likely when pulmonary vascular pressure is increased, and mitral regurgitation can result in pulmonary venous hypertension. HYPOTHESIS: There might be an association between MR and EIPH and the right ventricle (RV) of horses known to suffer repeated episodes of EIPH, as their hearts would be subject to higher pulmonary vascular pressures and cardiac output during training and hence increased RV afterload and preload. METHODS: An echocardiographic and auscultation study was conducted in 121 race-fit National Hunt Thoroughbreds. Cardiac auscultation and echocardiography were performed. A guided M-mode image of the RV just below the tricuspid valve was obtained from a right parasternal location and colour flow Doppler (CFD) used to interrogate the tricuspid valve and right atrium. The mitral valve was similarly examined from the left hemithorax. Severity of TR and MR by CFD was graded. Binary data on EIPH, based on whether the horse was perceived to have a clinically significant problem with EIPH, were determined retrospectively for each horse by the horses' primary care veterinary surgeon from medical and other records. Data were analysed using a standard logistic regression analysis approach. RESULTS: EIPH was significantly and positively associated with the systolic and diastolic dimensions of the RV (P = 0.017 and 0.011 respectively) and this association was not sensitive to the effects of age or weight. There were no significant associations between EIPH and TR or MR by auscultation or CFD (TR: auscultation P = 0.1; CFD P = 0.2 and MR: auscultation P = 0.07; CFD P = 0.37). CONCLUSIONS AND CLINICAL RELEVANCE: This study was limited by the method used to classify EIPH, but there was no association between EIPH and horse age, weight, TR or MR in this population of Thoroughbreds. Nevertheless, RV internal dimension was greater in horses obviously affected by EIPH, suggesting that factors resulting in EIPH may directly or indirectly affect RV remodelling in athletic horses.

Unusual vascular ring anomaly associated with a persistent right aortic arch in two dogs.

An unusual vascular ring anomaly consisting of a persistent right aortic arch and a left ligamentum arteriosum extending from the main pulmonary artery to an aberrant left subclavian artery and left aortic arch remnant complex was identified in a German shepherd dog and a great Dane. The left subclavian artery and left aortic arch remnant complex originated at the junction between the right distal aortic arch and the descending aorta and coursed dorsal to the oesophagus in a cranial direction. The attachment of the ligamentum arteriosum to the aberrant left subclavian artery was approximately 5 cm cranial to the point of origin of the aberrant left subclavian artery and left aortic arch remnant complex from the descending aorta in both dogs. This anomaly observed in both dogs is similar to an anomaly reported in humans, in which a persistent right aortic arch is found in conjunction with an aberrant left subclavian artery and a left aortic arch remnant (Kommerell's diverticulum). Surgical ligation and division of the left ligamentum arteriosum in both dogs, along with division of the left subclavian artery in the great Dane, resulted in resolution of clinical signs in both of the dogs in this report.

Quadricuspid aortic valve and associated abnormalities in a dog.

An 11-month-old, female Scottish terrier was presented with a history of a heart murmur. The electrocardiogram showed signs of left ventricular enlargement, and radiography confirmed generalized cardiomegaly. Echocardiography revealed four equally sized aortic valve cusps. A ventricular septal defect, with systolic left-to-right shunting, and aortic regurgitation into both ventricles were also present. The dog was free of clinical signs 1 year after diagnosis.

Comparison of systolic cardiac function before and after treatment of atrial fibrillation in horses with and without additional cardiac valve insufficiencies.

Clinical, electrocardiographic and echocardiographic examinations were conducted before therapy and 4 days after conversion to normal sinus rhythm in 15 horses with a history of atrial fibrillation of 2-6 months duration. Seven horses showed no other signs of cardiac disease. Four horses suffered additionally from mitral valve insufficiency, while six horses had aortic valve insufficiency, including two of the four horses with mitral valve insufficiency, but none had signs of congestive heart failure. Doppler echocardiographic estimates of various variables were made for assessment of systolic heart function. These included heart rate, stroke volume, cardiac output and cardiac output per kg of body weight (heart index). After conversion to normal sinus rhythm, the horses without heart valve insufficiency showed a statistically significantly decreased heart rate (-24%) and cardiac output (-3%), but an increase in stroke volume (+8.4%) and heart index (+9%). The horses with heart valve insufficiency experienced a statistically significant decrease in heart rate (-21%) after conversion to normal sinus rhythm, but showed an increase in all other variables. Cardiac output increased statistically significantly by 20%, stroke volume by 54% and heart index by 58%.