Echocardiographic evaluation of cardiac tamponade in dogs before and after pericardiocentesis: four cases (1984-1986)

The echocardiographic (M-mode and 2-dimensional) features (before and after pericardiocentesis) of 4 dogs with pericardial effusion and clinical evidence of cardiac tamponade were reviewed. M-Mode echocardiography revealed pericardial effusion, with exaggerated swinging motion of the heart and abnormal septal motion in all 4 dogs. In each case, 2-dimensional echocardiography demonstrated right ventricular diastolic free-wall collapse. Three dogs had right atrial diastolic collapse as well. Clinical signs improved, and right ventricular and right atrial diastolic collapse subsided after pericardiocentesis. Two-dimensional echocardiographic features of right atrial and ventricular collapse were used as indicators for determining the presence of cardiac tamponade.     

A case of juvenile form of dilated cardiomyopathy in a 6-month-old Shiba Inu dog

A 6-month-old Shiba Inu dog was brought to the Veterinary Medical Teaching Hospital because of a cough, exercise intolerance, and pulmonary edema. The dog had a Levine 2/6 systolic murmur. Transthoracic echocardiography revealed left atrial and ventricular dilatation (left atrium to aortic ratio: 2.8), mitral and tricuspid valve regurgitation, and severe left ventricular myocardial hypokinesia (fractional shortening was 11.8%). Bubble contrast echocardiography did not reveal a congenital shunt; therefore, the dog was clinically diagnosed with early onset dilated cardiomyopathy. From the first visit, the dog was treated with pimobendan, taurine, torasemide, and isosorbide dinitrate. After 435 days, echocardiography revealed that systolic function had not improved. On Day 465, atrial fibrillation was confirmed via electrocardiogram, and treatment with diltiazem hydrochloride was initiated. The dog continued to appear clinically stable thereafter, until it died suddenly 1087 days after the initial visit. A postmortem histopathological examination identified severe enlargement of the left atrial and ventricular chambers as well as attenuated wavy fibers in the ventricular myocardium, which confirmed dilated cardiomyopathy in a juvenile. This is the first report of a juvenile form of dilated cardiomyopathy in a Shiba Inu dog. This case report provides evidence that the extended prognosis of this dog differed from that in previously reported cases of dilated cardiomyopathy in young dogs.Key clinical message:This is the first reported case of a juvenile form of dilated cardiomyopathy in a Shiba Inu dog. This report provides evidence that the prognosis of this dog differed from that in previously reported cases of dilated cardiomyopathy in young dogs.     

Canine dynamic left ventricular outflow tract obstruction: assessment of myocardial function and clinical outcome

Objective : The aims of this study were (i) to evaluate echocardiographic findings and myocardial function including pulsed wave tissue Doppler imaging in dogs with naturally occurring dynamic left ventricular outflow tract obstruction and (ii) to investigate the clinical outcome and response to therapy in these dogs. Methods : Two cases were retrospectively reviewed and three cases were prospectively evaluated including clinical findings, diagnostic test results (including standard Doppler echocardiography and pulsed wave tissue Doppler imaging), response to treatment and outcome. The two retrospective cases received no treatment. Other cases were treated with a β‐blocker. Results : All dogs had a variable intensity left apical systolic murmur. Concentric left ventricular hypertrophy, systolic anterior motion of the mitral valve and scimitar‐shaped left ventricular outflow tract Doppler flow profile were present in all cases. Pulsed wave tissue Doppler imaging interrogation of the interventricular septum revealed E′/A′ reversal in all but one patient. Regression of left ventricular hypertrophy and total resolution of the dynamic left ventricular outflow tract obstruction were observed in all cases. Clinical Significance : Young dogs are affected with a possible terrier breed predisposition. Dynamic left ventricular outflow tract obstruction may be distinguished from canine hypertrophic cardiomyopathy as progressive resolution of echocardiographic abnormalities was documented. Pulsed wave tissue Doppler imaging abnormalities provide further evidence for significant diastolic dysfunction associated with the hypertrophy.     

Resting and dobutamine stress test induced serum concentrations of brain natriuretic peptide in German Shepherd dogs

Studies of clinical uses of brain natriuretic peptide (BNP) represent one of the most important advances in cardiology since the introduction of echocardiography as a clinical diagnostic procedure. Defining the clinical potential of BNP in canine cardiology has not been completed yet. The aim of this study is to measure BNP concentrations in healthy German Shepherd dogs of different ages as a baseline in resting and when conventional protocol of the dobutamine stress test (DST) is applied to dogs. Concentrations of BNP were measured in blood serum by the radioimmunoassay method. The values of BNP concentrations were compared to cardiac parameters obtained by standard cardiac diagnostic procedures (radiology, electrocardiography and echocardiography). No significant differences in serum BNP concentrations existed in dogs of different ages. A statistically significant increase in BNP concentrations was registered after DST. These changes in BNP concentrations were related to ST/T electrocardiographic changes, and correlated to changes in the left ventricular internal diameter in systole (LVESD). These data suggest that BNP is not increased in aged dogs with normal cardiac systolic function and renal function, and that myocardial ischemia leads to a significant increase in BNP concentrations even in dogs with normal left ventricular function.     

Resting and dobutamine stress test induced serum concentrations of brain natriuretic peptide in German Shepherd dogs

Studies of clinical uses of brain natriuretic peptide (BNP) represent one of the most important advances in cardiology since the introduction of echocardiography as a clinical diagnostic procedure. Defining the clinical potential of BNP in canine cardiology has not been completed yet. The aim of this study is to measure BNP concentrations in healthy German Shepherd dogs of different ages as a baseline in resting and when conventional protocol of the dobutamine stress test (DST) is applied to dogs. Concentrations of BNP were measured in blood serum by the radioimmunoassay method. The values of BNP concentrations were compared to cardiac parameters obtained by standard cardiac diagnostic procedures (radiology, electrocardiography and echocardiography). No significant differences in serum BNP concentrations existed in dogs of different ages. A statistically significant increase in BNP concentrations was registered after DST. These changes in BNP concentrations were related to ST/T electrocardiographic changes, and correlated to changes in the left ventricular internal diameter in systole (LVESD). These data suggest that BNP is not increased in aged dogs with normal cardiac systolic function and renal function, and that myocardial ischemia leads to a significant increase in BNP concentrations even in dogs with normal left ventricular function.     

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

OBJECTIVE: 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. ANIMALS: 8 mixed-breed adult dogs. PROCEDURE: 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. RESULTS: 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. CONCLUSIONS AND CLINICAL RELEVANCE: 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.     

Echocardiographic Detection of Flail Left Atrioventricular Valve Cusp From Ruptured Chordae Tendineae in 4 Dogs

Echocardiography was used to identify a flail left atrioventricular valve cusp caused by ruptured chordae tendineae in each of 4 dogs; two-dimensional echocardiography was superior to M-mode echocardiography in identifying the flail cusps. The following findings on two-dimensional imaging were characteristic: the tip of the flail cusp extended beyond the line of left atrioventricular valve cusp closure and pointed toward the left atrium in systole; the tip was thrust into the left ventricle, and then toward the left ventricular outflow tract in diastole, forming a convex surface to the cusp, which faced toward the left ventricle. The flail motion of the left atrioventricular valve cusp was best observed in the right parasternal long axis or left apical four-chamber views, in a plane parallel to the long axis of the left ventricle and left atrium. Rupture of chordae tendineae leading to flail cusp was attributed to chronic valve degeneration (endocardiosis) in all 4 dogs. Echocardiographic or clinical diagnoses were confirmed by postmortem gross and microscopic studies in all dogs.     

TRANSESOPHAGEAL ECHOCARDIOGRAPHY OF THE LEFT VENTRICULAR OUTFLOW TRACT, AORTIC VALVE AND ASCENDING AORTA IN BOXER DOGS WITH HEART MURMURS

The study was aimed at evaluating the anatomy of the left ventricular outflow tract, aortic valve, and ascending aorta by means of multiplane transesophageal echocardiography in Boxer dogs with left basilar heart murmurs and at comparing two-dimensional (2D) transthoracic to transesophageal echocardiography for the diagnosis of subaortic stenosis in this breed. Twenty-eight Boxers were included in the study and allocated to four groups according to physical and routine transthoracic 2D and Doppler echocardiography findings: group A--dogs with low grade (I-II/VI) heart murmurs without overt evidence of aortic stenosis (14 dogs); group B--dogs with type 1 subaortic stenosis (seven dogs); group C--dogs with type 2 subaortic stenosis (five dogs); group D--dogs with type 3 subaortic stenosis (two dogs). Anatomic lesions were not discovered by transesophageal echocardiography in dogs belonging to group A. Transesophageal imaging confirmed the type of subaortic stenosis, as graded by transthoracic echocardiography, in diseased animals (groups BCD). Morphologic information obtained by transesophageal echocardiography in Boxer dogs was similar to that obtained by transthoracic echocardiography.     

Noninvasive estimation of cardiac systolic function using continuous-wave Doppler echocardiography in dogs with experimental mitral regurgitation

OBJECTIVE: To evaluate the feasibility of noninvasive estimation of cardiac systolic function using transthoracic continuous-wave Doppler echocardiography in dogs with mitral regurgitation. PROCEDURE: Seven mongrel dogs with experimental mitral regurgitation were used. Left ventriculography and measurement of pulmonary capillary wedge pressure were performed under inhalational anaesthesia. A micromanometer-tipped catheter was placed into the left ventricle and transthoracic echocardiography was carried out. The peak rate of left ventricular pressure rise (peak dP/dt) was derived simultaneously by continuous-wave Doppler and manometer measurements. The Doppler-derived dP/dt was compared with the catheter-measured peak dP/dt in the dogs. RESULTS: Classification of the severity of mitral regurgitation in the dogs was as follows: 1+, 2 dogs; 2+, 1 dog; 3+, 2 dogs; 4+, 1 dog; and not examined, 1 dog. We were able to derive dP/dt from the transthoracic continuous-wave Doppler echocardiography in all dogs. Doppler-derived dP/dt had a significant correlation with the catheter-measured peak dP/dt (r = 0.90, P < 0.0001). CONCLUSION: It was demonstrated that transthoracic continuous-wave Doppler echocardiography is a feasible method of noninvasive estimation of cardiac systolic function in dogs with experimental mitral regurgitation and may have clinical usefulness in canine patients with spontaneous mitral regurgitation.     

Pathophysiologic mechanism of cardiac dysfunction in experimentally induced heartworm caval syndrome in dogs: an echocardiographic study

In dogs with experimentally induced heartworm infection, the onset of caval syndrome (CS) was characterized by a murmur, loudest over the tricuspid valve, and a large worm mass in the right ventricular lumen detectable during diastole by use of M-mode echocardiography. Two-dimensional echocardiography indicated that the worm mass was located in the right atrium and venae cavae and was "flowing" into the right ventricle during rapid diastolic filling. Paradoxical septal motion and vigorous right ventricular cranial wall motion also were observed. Other echocardiographic changes included decreased size of the left atrium and ventricle, aortic root, and ratio of left-to-right ventricular diastolic luminal diameter, compared with values obtained 6 months after experimentally induced heartworm infection. Right ventricular end diastolic diameter increased considerably. Most echocardiographic indices of left ventricular function (fractional shortening, velocity of circumferential fiber shortening, ejection fraction, and preejection period) were not altered appreciably, but estimates of cardiac index and stroke volume were markedly decreased. Electrocardiography revealed ventricular and supraventricular premature complexes in 7 of the 8 dogs studied, evidence of right ventricular enlargement in 6 of the 8 dogs studied, and increased mean heart rate, compared with that measured 6 months after inoculation of infective larvae, before the onset of CS. Cardiac catheterization was performed in 3 days at the onset of CS. Severe pulmonary arterial and right ventricular hypertension and decreased cardiac index (compared with values obtained before inoculation) were observed. Evidence of right ventricular inflow obstruction was not detected. Mean aortic blood pressure decreased with the onset of CS, but right ventricular end diastolic pressure increased.(ABSTRACT TRUNCATED AT 250 WORDS)     

Echocardiographic and clinical signs of canine dilated cardiomyopathy

The clinical signs, electrocardiograms and echocardiograms of 12 dogs with dilated cardiomyopathy of large breeds and congestive heart failure were reviewed. There was a high prevalence of males (11 dogs) and of the Doberman breed (7 dogs). Seven dogs had atrial fibrillation. The echocardiograms revealed significant increases in left ventricular and left atrial dimensions. The shortening fraction (%ΔD), aortic root excursion and left ventricular wall excursion were all significantly decreased, documenting a decrease in contractile function of the left ventricle that, together with the cardiac enlargement characterize this disease. The advantages of obtaining these functional parameters non-invasively are emphasized.     

Noninvasive estimation of cardiac systolic function using continuous-wave Doppler echocardiography in dogs with experimental mitral regurgitation

Objective To evaluate the feasibility of noninvasive estimation of cardiac systolic function using transthoracic continuous-wave Doppler echocardiography in dogs with mitral regurgitation.
Procedure Seven mongrel dogs with experimental mitral regurgitation were used. Left ventriculography and measurement of pulmonary capillary wedge pressure were performed under inhalational anaesthesia. A micromanometer-tipped catheter was placed into the left ventricle and transthoracic echocardiography was carried out. The peak rate of left ventricular pressure rise (peak dP/dt) was derived simultaneously by continuous-wave Doppler and manometer measurements. The Doppler-derived dP/dt was compared with the catheter-measured peak dP/dt in the dogs.
Results Classification of the severity of mitral regurgitation in the dogs was as follows: 1+, 2 dogs; 2+, 1 dog; 3+, 2 dogs; 4+, 1 dog; and not examined, 1 dog. We were able to derive dP/dt from the transthoracic continuous-wave Doppler echocar-diography in all dogs. Doppler-derived dP/dt had a significant correlation with the catheter-measured peak dP/dt (r = 0.90, P < 0.0001).
Conclusion It was demonstrated that transthoracic continuous-wave Doppler echocardiography is a feasible method of noninvasive estimation of cardiac systolic function in dogs with experimental mitral regurgitation and may have clinical usefulness in canine patients with spontaneous mitral regurgitation.     

The effect of hypothyroidism on cardiac function in dogs

The thyroid hormones have direct and indirect effects on the heart. So it is possible that depression of left ventricular function is associated with hypothyroidism. This publication describes cardiac findings (auscultation, electrocardiography, echocardiography) in ten hypothyroid dogs. Low heart rates, reduced R-amplitudes and bradycardic arrhythmias (first and second-degree AV block) were found on the electrocardiogram before treatment. On the echocardiograms most of the dogs showed reduced contractillity and reduced left ventricular wall thickness. Seven dogs were reexamined after levothyroxine supplementation. Effects of treatment were increased heart rates and R-amplitudes as well as disappearance of the bradycardic arrhythmias in electrocardiographic examination. The echocardiographic examination showed increased contractility and increased left ventricular wall thickness.     

Clinical, echocardiographic, and electrocardiographic abnormalities in Boxers with cardiomyopathy and left ventricular systolic dysfunction: 48 cases (1985-2003)

OBJECTIVE: To identify clinical, echocardiographic, and electrocardiographic abnormalities in Boxers with cardiomyopathy and echocardiographic evidence of left ventricular systolic dysfunction. DESIGN: Retrospective study. ANIMALS: 48 mature Boxers. PROCEDURE: Medical records were reviewed for information on age; sex; physical examination findings; and results of electrocardiography, 24-hour ambulatory electrocardiography, thoracic radiography, and echocardiography. RESULTS: Mean age of the dogs was 6 years (range, 1 to 11 years).Twenty (42%) dogs had a systolic murmur, and 9 (19%) had ascites. Congestive heart failure was diagnosed in 24 (50%) dogs. Seventeen (35%) dogs had a history of syncope. Mean fractional shortening was 14.4% (range, 1% to 23%). Mean left ventricular systolic and diastolic diameters were 4.5 cm (range, 3 to 6.3 cm) and 5.3 cm (range, 3.9 to 7.4 cm), respectively. Twenty-eight (58%) dogs had a sinus rhythm with ventricular premature complexes (VPCs), and 20 had supraventricular arrhythmias (15 with atrial fibrillation and 5 with sinus rhythm and atrial premature complexes). Sixteen of the dogs with supraventricular arrhythmias also had occasional VPCs. Morphology of the VPCs seen on lead II ECGs was consistent with left bundle branch block in 25 dogs, right bundle branch block in 8, and both in 11. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that Boxers with cardiomyopathy and left ventricular dysfunction frequently have arrhythmias of supraventricular or ventricular origin. Whether ventricular dysfunction was preceded by electrical disturbances could not be determined from these data, and the natural history of myocardial disease in Boxers requires further study.     

Echocardiographic ratio indices in overtly healthy Boxer dogs screened for heart disease

BACKGROUND: Boxer dogs are routinely screened by echocardiography to exclude congenital and acquired heart disease. Individuals of a given breed may span a large range of body sizes, potentially invalidating linear regression of M-mode measurements against body weight. Echocardiographic ratio indices (ERIs) provide a novel method of characterizing echocardiographic differences between Boxers and other dog breeds. HYPOTHESIS: ERIs obtained from overtly healthy Boxer dogs presented for cardiac screening will be different from ERIs established for normal non-Boxer dogs, and those differences will be unrelated to aortic velocity or systolic blood pressure. ANIMALS: Eighty-one Boxers with no outward clinical signs of heart disease were studied. METHODS: All dogs were examined by 2-dimensional, M-mode, and Doppler echocardiography. M-mode measurements were used to perform ERI calculations, and the indices in Boxers were compared between Boxers with varying severity of arrhythmia and those of normal non-Boxer dogs. RESULTS: Differences in weight-based ERIs, which reflect increased thickness of the left ventricular free wall (LVW) and interventricular septum (IVS) and smaller aortic size, were found in overtly healthy Boxer dogs compared with normal non-Boxer dogs. ERIs of left atrial and LV cavity size in overtly healthy Boxers were not significantly different from those of non-Boxer dogs. CONCLUSIONS AND CLINICAL IMPORTANCE: Boxer dogs may have an increased relative thickness of the LVW and IVS that is independent of aortic size, aortic velocity, or arterial blood pressure, and this morphology should be taken into consideration when screening Boxers by echocardiography.     

QUANTITATIVE CROSS-SECTIONAL ECHOCARDIOGRAPHY IN THE NORMAL DOG

Two-dimensional echocardiography was performed on 18 unanesthetized, normal dogs (4.5 to 30 kg). Measurements of wall thickness, intracavitary dimensions, and cross-sectional area of the left atrium, left ventricle, and aorta were made. Satisfactory data were obtained from 17 dogs, and were used to determine normal values. Normal data were tested for significant correlation to body weight (kg) by linear regression. Repeatability was studied in six dogs examined, on three separate occasions, during a 5-day period. Differences between values obtained on different days were evaluated by analysis of variance.
Satisfactory qualitative echocardiograms were repeatedly obtained by using consistent sites of transducer placement and by identifying internal cardiac structures. These tomographic planes were highly reproducible, with only ventricular length, and some views of the ventricular septum, showing statistically significant (P < 0.05) differences. Almost all linear and area measurements were significantly correlated to body size, while most indices of left ventricular function were independent of body weight. Dimensions obtained from the left and right parasternal position were nearly identical. Cross-sectional echocardiography allows repeatable assessment of cardiac anatomy, and it should prove useful for identification and quantitation of heart disease in the dog.     

Heart rate variability in relation to severity of mitral regurgitation in Cavalier King Charles spaniels

Heart rate variability was measured in 81 Cavalier King Charles spaniels to investigate if it could be used to evaluate the severity of mitral regurgitation and to predict decompensation. Heart rate variability was assessed by the natural logarithm of the variance of the R-R intervals for 20 consecutive beats obtained from electrocardiographic recordings. Twenty-two of the dogs were clinically normal and 59 had mitral regurgitation caused by chronic valvular disease. The severity of mitral regurgitation was evaluated by echocardiography and thoracic radiography. Heart rate variability was found to be reduced (P < 0.001) among dogs with severe left atrial and ventricular dilatation and clinical signs of congestion. No significant differences in heart rate variability were found among normal dogs, dogs with only cardiac murmur, and dogs with echocardiographic evidence of slight to moderate left atrial and ventricular dilatation. Overall, an association was found between heart rate variability and left atrial to aortic root ratio and left ventricular end diastolic diameters (r = 0.72 and 0.64, respectively, P < 0.001), as well as heart and respiratory rate (r = 0.80 and 0.69, respectively, P < 0.001). Multiregression analysis showed that, in order of importance, heart rate, left atrial diameter and respiratory rate had significant effects on heart rate variability. Among these parameters, heart rate variability and left atrial diameter were found to be most efficient in separating decompensated dogs from compensated. It is concluded that heart rate variability may provide the clinician with valuable information when assessing the severity of mitral regurgitation caused by chronic valvular disease.     

Normal and paradoxical ventricular septal motion in the dog

Normal and paradoxical ventricular septal motions were studied in dogs, using M-mode and 2-dimensional echocardiography. Normal ventricular septal motion was evaluated, using 35 clinically healthy dogs (group I), and was compared with characteristics of septal motion measured in 12 dogs with right ventricular overload (group II) and 14 dogs with left-sided heart disease (group III). Normal ventricular septal motion consisted of a series of active and passive anterior (right cranial) and posterior (left caudal) movements that were subjectively evaluated and quantitated during segments of the cardiac cycle. Maximum excursion of the ventricular septum occurred during systole, was directed toward the left ventricle, and was related to body size. Determination of a normalized radius of septal curvature from analysis of 2-dimensional echocardiogram indicated that the septal arc formed part of a generally circular left ventricle in group I dogs. In contrast to these findings, group II dogs with right ventricular pressure and volume overloads exhibited reduced systolic septal excursion, diminished or flat septal motion, and paradoxical systolic septal motion. Normalized radius of septal curvature was significantly greater in group II dogs than in group I or group III dogs. Septal motion and radius of septal curvature in dogs comprising group III were not significantly different from normal during most phases of the cardiac cycle. Results of this study support the concept that septal motion is a reflection of overall left ventricular shape and that abnormalities in ventricular septal motion, namely flat or paradoxical septal motion, should cause the clinician to suspect right ventricular volume or pressure overload.     

N-terminal pro B-type natriuretic peptide and left ventricular diameter independently predict mortality in dogs with mitral valve disease

Objectives : To determine whether natriuretic peptide concentrations would predict all cause mortality in dogs with degenerative mitral valve disease. Methods : One hundred dogs with naturally occurring degenerative mitral valve disease were prospectively recruited for this longitudinal study. Analysis of outcome was undertaken for 73 dogs for which the outcome was known. Dogs underwent physical examination, electrocardiography and echocardiography. Natriuretic peptide concentrations were measured by Enzyme-linked immunosorbent assay. The ability of natriuretic peptide concentrations, clinical, electrocardiographic and echocardiographic data, to predict all cause mortality was determined using univariable and multivariable Cox proportional hazards analyses. Results : Thirty dogs died during the period of follow-up. Two variables were independently predictive of all cause mortality; these were the normalised left ventricular end-diastolic diameter and the N-terminal pro B-type natriuretic peptide concentration. An increase of the left ventricular end-diastolic diameter by 0.1 increased the hazard of all cause mortality by 20% (95% confidence interval: 4 to 37%, P=0.01) and a 100 pmol/l increase in N-terminal pro B-type natriuretic peptide increased the hazard by 7% (95 confidence interval: 2 to 11%, P=0.003). Clinical Significance : N-terminal pro B-type natriuretic peptide concentration and left ventricular end-diastolic diameter are significantly and independently predictive of all cause mortality in dogs with degenerative mitral valve disease.     

MITRAL ANNULUS MOTION AS DETERMINED BY M-MODE ECHOCARDIOGRAPHY IN NORMAL DOGS AND DOGS WITH CARDIAC DISEASE

M-mode echocardiography was used to assess apical mitral annulus motion (MAM) in 103 normal dogs and 101 dogs with cardiac disease, to obtain information on systolic left ventricular long axis function. In normal dogs, a close relationship was found between MAM and body weight (r = 0.80, P < 0.001). There was a weak correlation between MAM and heart rate (r = -0.25, P < 0.05), but no correlation between MAM and age or left ventricular shortening fraction (P > 0.05). Mean MAM (95% confidence intervals) were established for normal dogs of differing body weight, and were 0.70 cm (0.65 to 0.75) in dogs < 15 kg, 1.08 cm (1.03 to 1.13) in dogs weighing 15 to 40 kg, and 1.51 cm (1.21 to 1.81) in dogs > 40 kg. "Cut-off" values to define decreased MAM for normal dogs of differing body weight were 0.45 cm (dogs < 15 kg), 0.80 cm (dogs 15-40 kg), and 1.20 cm (dogs > 40 kg). In dogs with cardiac disease, median MAM was normal in mitral valve endocardiosis or aortic stenosis, but significantly decreased (P < 0.05) in dilated cardiomyopathy. All dogs with mitral valve endocardiosis (n = 54) or aortic stenosis (n = 26) had MAM above the above-mentioned "cut-off" values, suggesting normal or increased left ventricular longitudinal systolic shortening, whereas 81% (17/21) of dogs with dilated cardiomyopathy had MAM below the "cut-off" value, indicating decreased long axis systolic function. It is concluded that MAM may be used to evaluate systolic left ventricular long axis performance in dogs and may add useful information on global left ventricular contraction dynamics.