Congenital cardiac disease in dogs

Thoracic conformation, age, amount of body fat, and stage of respiration and cardiac contraction affect the cardiac silhouette. Deep-chested dogs have an upright, narrow cardiac silhouette about 2 1/2 intercostal spaces wide, while barrel-chested dogs have a round, wide silhouette about 3 1/2 intercostal spaces wide. On LAT films the vessels to a lung lobe should be of equal size and 0.25-1.2 times the diameter of the upper third of the 4th rib at the 4th intercostal space. On DV projections, vessels to the caudal lung lobe should be no larger than the diameter of the 9th rib. Signs of right ventricular enlargement include loss of the cranial waist, increased width of the cardiac silhouette, increased sternal contact of the heart, and an elevated cardiac apex. Signs of left ventricular enlargement include an elevated carina, loss of the caudal waist, and a more perpendicular caudal cardiac border. Signs of left atrial enlargement include separation of mainstem bronchi, compression of the bronchus to the left caudal lung lobe, and an increased distance from the carina to the dorsal border of the caudal vena cava. Enlargement of the aorta and main pulmonary artery segment on a LAT view appears as a soft tissue density obscuring the cranial waist. Pulmonary vascular fields are usually hypervascular in patent ductus arteriosus and interventricular septal defects, normal in uncomplicated aortic or pulmonic stenosis, and hypovascular in tetralogy of Fallot.     

Von Willebrand's disease in dogs

Von Willebrand's disease, the most common, mild, inherited bleeding disorder of animals, is an autosomal trait generally causing high morbidity and low mortality and affecting many breeds of dogs. Clinical signs include hematuria, epistaxis, gingival or genital mucosal bleeding, lameness, and prolonged bleeding from cut nails or wounds. Concurrent hypothyroidism exacerbates the disease. Affected dogs and carriers should not be bred or should be tested for von Willebrand's factor before breeding. Treatment involves IV infusion of fresh whole blood or plasma, at 3-5 ml/lb, with topical use of hemostatic compounds, and avoidance of drugs that interfere with hemostasis.     

Familial renal disease in dogs

Juvenile renal disease in dogs has been encountered in over 20 breeds but in only nine of these (cocker spaniel, Norwegian elkhound, lhasa apso, shih tzu, samoyed, dobermann, standard poodle, soft-coated wheaten terrier and bull terrier) have familial nephropathies been reported, and in only two (samoyed and cocker spaniel) has the exact mode of inheritance been elucidated. Reasons for this unsatisfactory state of affairs are: 1 Renal failure in young dogs may not be due to a familial nephropathy, and while helpful diagnostic information may be gained from blood and urine analysis, accurate diagnosis of the specific type of renal disease requires examination of renal biopsy or post mortem material by an experienced pathologist. 2 Not all affected animals show clinical signs at the same age, making collection of data, often from widely dispersed animals, both difficult and slow. 3 The disease process in one breed may be very different from that in another, so that each breed has to be investigated separately. 4 There has to be a willing determination to face the problem by individual breed clubs, with the commitment of a large number of breeders, owners and veterinary surgeons. Resistance or inertia at any level will prevent or delay successful investigation and possible prevention of the disease.     

Congenital cardiac disease in dogs

Patent ductus arteriosus (PDA) is thought to be inherited and occurs twice as often in females as in males, most commonly in Poodles, Collies, Cocker Spaniels and Shetland Sheepdogs. About half of untreated dogs develop left-sided heart failure by 8 months of age. Clinical signs include coughing, decreased exercise tolerance, pulmonary edema, a "machinery" murmur in the pulmonic-aortic region, and a bounding pulse. An ECG may reveal an increased amplitude of the R wave and a lengthened P wave. Plain LAT films reveal loss of the cranial and caudal cardiac waists, increased sternal contact of the heart, increased width and straightened caudal border of the cardiac silhouette, elevated carina, and an enlarged left atrium. Changes on plain DV films include an elongated cardiac silhouette, enlarged right ventricle, and 3 bulges on the left side of the cardiac silhouette. Nonselective angiocardiography can be used for a definitive diagnosis and to demonstrate a reverse right-to-left PDA, in which the ascending aorta, brachiocephalic trunk and left subclavian artery are not opacified by contrast medium. Animals with a right-to-left shunt PDA are cyanotic in caudal body parts. Treatment of left-to-right shunt PDA involves ligation with 2 nonabsorbable sutures. A right-to-left shunt PDA should not be ligated but is treated by restricted exercise and periodic phlebotomy.     

Congenital cardiac disease in dogs

Patent ductus arteriosus, aortic stenosis, ventricular septal defect, pulmonic stenosis and tetralogy of Fallot are the most frequently reported cardiac anomalies of dogs. Systolic murmurs occur after the first heart sound but before the second, while diastolic murmurs occur after the second heart sound. Murmurs associated with the pulmonic, aortic and mitral valves are best heard at the left intercostal spaces 3, 4 and 5, respectively, and those of the tricuspid valve at the right intercostal space 3 or 4. Mucosae at both ends of the animal should be examined for cyanosis. Right ventricular enlargement is characterized by a mean electrical axis greater than 100 degrees, a Q wave amplitude greater than 0.5 mv in leads II, III and AVF, and a positive T wave in lead V10. Left ventricular enlargement causes an axis of less than 40 degrees, a QRS complex duration greater than 0.06 seconds, an R wave amplitude greater than 3 mv, and a slurred or depressed ST segment. Atrial enlargement is characterized by a P wave duration greater than 0.04 seconds and a P wave amplitude greater than 0.4 mv. The cardiac silhouette is more upright and round on DV radiographs than on VD projections.     

Congenital cardiac disease in dogs

Aortic stenosis is a heritable cardiac anomaly most common in German Shepherds, Boxers and Newfoundlands, and less common in Pugs, English Bulldogs, Boston Terriers, Fox Terriers, Schnauzers and Bassets. Clinical signs are associated with secondary left-sided heart failure and include coughing, moist rales, exercise intolerance, arrhythmias and a weak femoral pulse. It causes an ejection-type crescendo-decrescendo, systolic murmur best heard on the left side near the elbow. The ECG may be normal or may show signs of left ventricular hypertrophy, including an axis of less than 40 degrees, a QRS complex of greater than 60 seconds in duration, R waves greater than 3 mv in amplitude, ST segment slurring or depression, or T waves of an amplitude greater than 25% of that of R waves. A LAT radiograph usually reveals an enlarged cardiac silhouette, loss of the cranial cardiac waist, and normal pulmonary vasculature, while DV projections show an elongated cardiac silhouette, rounding of the left ventricular border, and a normal descending aorta. Nonselective angiocardiography reveals poststenotic dilatation of the aorta. Treatment of severely affected dogs involves surgical correction.     

Congenital cardiac disease in dogs

Ventricular septal defect (VSD) generally occurs high in the membranous septum rather than lower in the muscular portion. The English Bulldog and Siberian Husky may be predisposed. Clinical signs include a holosystolic or crescendo-decrescendo murmur best heard low on the right side at the 3rd-4th intercostal space and, with large defects, pulmonary congestion, exercise intolerance, cyanosis and ascites. The ECG is normal unless the right ventricle is hypertrophied, which causes right axis deviation and other electrocardiographic signs of right-sided heart enlargement. Plain film thoracic radiographs reveal signs of right-sided heart enlargement but often are not diagnostic. Nonselective angiocardiography is often not useful in diagnosing VSD with a left-to-right shunt of blood. Selective angiocardiography, in which contrast medium is injected directly into the left ventricle via a catheter, is the method of choice for diagnosis of VSD. Dogs with a small VSD remain asymptomatic, but those with large defects require surgical correction with a prosthetic septal pathic or pulmonary artery band.     

Congenital cardiac disease in dogs

Pulmonic stenosis is caused by a malformed pulmonic valve, stricture of the right ventricular outflow tract or stricture of the pulmonary artery. English Bulldogs, Beagles, Samoyeds, Fox Terriers and Chihuahuas are predisposed. Clinical signs in severely affected dogs include exercise intolerance, stunting, dyspnea, syncope and ascites. Auscultation reveals a high-frequency, crescendo-decrescendo murmur during systole, loudest over the left side of the thorax, near the sternal cardiac border. An ECG may reveal a right-axis deviation of greater than 120 degrees, S waves in leads I, II and III, deep S waves in CV6LL, CV6LU and V10, Q waves deeper than 0.5 mv in leads II, III and AVF, and positive T waves in lead V10. Plain film LAT thoracic radiographs reveal an elevated carina, increased sternal contact of the heart, loss of the cranial cardiac waist and a widened cardiac silhouette, with normal pulmonary vasculature. A DV projection reveals an inverted "D" shape of the right ventricle and a pulmonary artery bulge. A nonselective angiocardiogram reveals poststenotic dilation of the main pulmonary artery. Treatment involves surgical correction of the stenosis.     

Comparison of P-wave dispersion in healthy dogs,dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction

Background

P-wave dispersion (P_d) is a new ECG index used in human cardiology and veterinary medicine. It is defined as the difference between the maximum and the minimum P-wave duration recorded from multiple different ECG leads. So far no studies were performed assessing the importance of P-wave dispersion in dogs.

Methods

The current study was aimed at determining proper value of P_d in healthy dogs (group I), dogs with chronic valvular disease (group II) and dogs with disturbances of supraventricular conduction (group III). The tests were carried out in 53 healthy dogs, 23 dogs with chronic valvular disease and 12 dogs with disturbances of supraventricular conduction of various breeds, sexes and body weight from 1,5 to 80 kg, aged between 0,5 and 17 years, submitted to the ECG examination. ECG was acquired in dogs in a standing position with BTL SD-8 electrocardiographic device and analyzed once the recording was enlarged. P-wave duration was calculated in 9 ECG leads (I, II, III, aVR, aVL, aVF, V1, V2, V4) from 5 cardiac cycles.

Results

The proper P-wave dispersion in healthy dogs was determined at up to 24 ms. P-wave dispersion was statistically significant increased (p < 0.01) in dogs with chronic valvular disease and dogs with disturbances of supraventricular conduction. In dogs with the atrial enlargement the P-wave dispersion is also higher than in healthy dogs, although no significant correlation between the size of left atria and Pd was noticed (p = 0.1, r = 0,17).

Conclusions

The P-wave dispersion is a constant index in healthy dogs, that is why it can be used for evaluating P wave change in dogs with chronic valvular disease and in dogs with disturbances of supraventricular conduction.     

Indocyanine green disposition in healthy dogs and dogs with mild, moderate, or severe dimethylnitrosamine-induced hepatic disease.

Disposition kinetics of indocyanine green (ICG) were used to evaluate hepatic function in healthy Beagles (group 1; n = 6) and Beagles with progressive hepatic disease induced by oral administration of dimethylnitrosamine, a hepatospecific toxin. Three classes of hepatic disease were defined by histologic features: mild (group 2; n = 5), moderate (group 3; n = 6), and severe (group 4; n = 5). Disposition of ICG was studied 3 weeks following the last dose of toxin. A rapid IV injection of 0.5 mg of ICG/kg was administered and serum samples were obtained at certain intervals during 60-minute periods. Serum ICG was analyzed by use of visible spectrophotometry. Disposition kinetics were determined from serum ICG concentrations vs 15- and 60-minute time curves and compared between one another and among groups. Data based on 60-minute time curves were not significantly different from those based on 15-minute curves. Area under the curve for ICG was greatest in group 3. Clearance of ICG was decreased and mean resident time was increased in groups 3 and 4, compared with those in groups 1 and 2. When disposition data (60 minutes) were normalized for differences in hepatic weight among dogs, group-3 mean resident time was significantly greater than that of group 4. This study supports the diagnostic benefits of using ICG disposition kinetics as a method of evaluating hepatic function in dogs with progressive liver disease.     

Von Willebrand's disease in dogs in the United Kingdom

An assay for the measurement of von Willebrand factor antigen has been established. In a period of 18 months, 13 dogs have been identified as suffering from von Willebrand's disease. The affected animals had levels of von Willebrand factor antigen which ranged from undetectable to 43 per cent of normal. Factor VIII levels were also reduced. Haemorrhagic episodes were usually associated with trauma or surgery, and often required transfusion with fresh blood or plasma to arrest haemorrhage.     

Cardiovascular disease and nephritis in dogs

Data on arteriosclerosis, valvular endocardosis, myocardial lesions, nephritis, age, sex, obesity, physical activity, serum cholesterol, blood pressure, relative heart weight and thyroid activity of fifty-eight dogs were collected. Endothelial plaques of the aorta was observed in 77.6% of the dogs, lipid infiltration in 39.7%, valvular endocardosis in 59.6%, myocardial lesions in 29.3% and nephrotic changes in 55.1%. The parameters were correlated with each other and a factor analysis was performed. Three factors were found: the first factor combined endocardosis, lipid infiltration, aortic plaques and nephritis with age; the second factor obesity and high serum cholesterol with low relative heart weight; and the third one myocardial lesions, lipid infiltration, aortic plaques and male sex with blood pressure. Age, blood pressure and sex seem to be ‘risk factors’ for arteriosclerosis in dog as they are in man. Obesity also shows association with endocardosis and nephritis and high serum cholesterol with myocardial lesions. Résumé. On a rassemblé des données concernant cinquante-huit chiens sur: l'artériosclérose, l'endocardose valvaire, les lésions du myocarde, la néphrite, l'âge, le sexe, l'obésité, l'activité physique, le sérum cholestérol, la tension, le poids relatif du coeur et l'activité de la glande tyhroïde. On a observé des plaques endothéliales de l'aorte chez 77.6% des chiens, des infiltrations lipides chez 39.7%, des endocardoses valvaires chez 59.6%, des lésions du myocarde chez 29.3% et des variations néphrotiques chez 55.1%. Les paraméters ont été corrélatifs et on a utilisé une analyse des facteurs. On a trouvé trois facteurs: le premier facteur combinant une endocardose, une infiltration des lipides, des plaques aortiques et de la néphrite avec de l'âge; le second facteur combinant une obésité et un taux élevé de sérum cholestérol avec un poids de coeur relativement lèger; et le troisième combinant des lésions du myocarde, une infiltration lipide, des plaques aortiques et le sexe mâle avec de la tension. L'âge, la tension et le sexe semblent être les facteurs risques pour l'artériosclérose chez les chiens, de même que chez l'homme. L'obèsitè montre aussi une certaine association avec l'endocardose et le néphrite, et le sérum cholestérol à taux élevé présente une certaine association avec les lésions du myocarde. Zusammenfassung. Daten über Arteriosklerose, valväre Herzinnenwanddegeneration, myo-kardische Läsionen, Nephritis, Alter, Geschlect, Fettleibigkeit, Körperliche Tätigkeit, Cholesterol Serum, Blutdruck, relatives Herzegewicht und Schilddrüsentätigkeit wurde von acht und fünfzig Hunden gesammelt. Endothelbezügliche Plaques der Aorta wurden in 77.6% der Hunde festgestellt, lipide Infiltrationen in 39.7%, valväre Herzinnenwanddegeneration in 59.6%, myokardische Läsionen in 29.3%, und nephrotische Veränderungen in 55.1%. Die Parameter wurden miteinander korreliert und eine Faktorenanalyse ausgeführt. Man fand drei Faktoren: der erste Faktor verband Herzinnenwanddegeneration, lipide Infiltration, aortische Plaques und Nephritis im Alter; der zweite Faktor verband Fettleibigkeit ind hohes Cholesterol Serum mit niedrigem relativem Herzgewicht; und der dritte Faktor verband myokardische Läsionen, lipide Infiltration, aortische Plaques, und das männliche Geschlecht mit Blutdruck. Alter, Blutdruck und Geschlecht scheinen “Gefahrenpunkte” für Arteriosklerose in Hunden sowie in Menschen. Fettleibigkeit zeigt auch Verbindung zu Herzinnenwanddegeneration und Nephritis, und hohes Cholesterol Serum mit myokardischen Läsionen.