Background: The impact of pulmonary hypertension (PH) on right ventricular systolic function is difficult to assess. Tricuspid annular plane systolic excursion (TAPSE) is an echocardiographic measurement of right ventricular systolic function and a strong predictor of outcome in human PH patients.Hypothesis/Objectives: Determine a reference range for TAPSE in healthy dogs, and quantify TAPSE in dogs with PH. It is hypothesized that TAPSE is lower in dogs with PH compared with a reference group, and decreases as PH worsens.Animals: Fifty normal dogs and 30 dogs with PH. Methods: TAPSE was measured by 2-dimensional echocardiography-guided M-mode from the left apical 4-chamber view. Peak systolic tricuspid valve regurgitation jet velocity was measured by continuous-wave Doppler to estimate right ventricular-to-right atrial pressure gradient. PH was subjectively classified as mild, moderate, and severe.Results: There was a curvilinear correlation between TAPSE and body weight. The upper and lower limits of the 95% reference interval were determined by quantile regression. Interobserver and intraobserver agreement was adequate with a coefficient of variation <10%. There were significant differences when comparing dogs with PH and the healthy group, as well as between the PH subgroups (P < .01), except between dogs with mild and moderate PH (P = .99). Only dogs in the severe PH group had TAPSE values that were mostly below the lower limit of the reference interval.Conclusions and Clinical Importance: TAPSE is easily obtainable with acceptable inter and intraobserver agreement. TAPSE is decreased in PH and below the reference interval in most dogs with severe PH.

Pulmonary edema is the most common complication of left-sided heart failure in dogs and early detection is important for effective clinical management. In people, pulmonary edema is commonly diagnosed based on transthoracic ultrasonography and detection of B line artifacts (vertical, narrow-based, well-defined hyperechoic rays arising from the pleural surface). The purpose of this study was to determine whether B line artifacts could also be useful diagnostic predictors for cardiogenic pulmonary edema in dogs. Thirty-one normal dogs and nine dogs with cardiogenic pulmonary edema were prospectively recruited. For each dog, presence or absence of cardiogenic pulmonary edema was based on physical examination, heartworm testing, thoracic radiographs, and echocardiography. A single observer performed transthoracic ultrasonography in all dogs and recorded video clips and still images for each of four quadrants in each hemithorax. Distribution, sonographic characteristics, and number of B lines per thoracic quadrant were determined and compared between groups. B lines were detected in 31% of normal dogs (mean 0.9 ± 0.3 SD per dog) and 100% of dogs with cardiogenic pulmonary edema (mean 6.2 ± 3.8 SD per dog). Artifacts were more numerous and widely distributed in dogs with congestive heart failure (P < 0.0001). In severe cases, B lines increased in number and became confluent. The locations of B line artifacts appeared consistent with locations of edema on radiographs. Findings from the current study supported the use of thoracic ultrasonography and detection of B lines as techniques for diagnosing cardiogenic pulmonary edema in dogs.

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An increased tracheal bifurcation angle on the dorsoventral projection is described as a sign of left atrium enlargement in dogs, with a normal range of 60-90 degrees reported. However in people, this angle is a poor indicator of left atrial size. Our purpose was to evaluate the value of the tracheal bifurcation angle for differentiating normal from enlarged left atrium in dogs. Dorsoventral radiographs and echocardiograms of 33 healthy and 73 dogs with confirmed degenerative myxomatous mitral valve disease were evaluated. Left atrial size was classified according to the echocardiographic left atrium to aorta ratio, as normal, mildly, moderately, or severely enlarged. Independent samples t-tests were used to compare the bifurcation angle between groups. A significant difference was observed between the angle of dogs with normal left atrium (68.1 +/- 8.5 degrees, range: 51.3-92.4 degrees) and dogs with enlarged left atrium (75.8 +/- 8.2 degrees, range: 57.3-91.7 degrees). A significant difference was also noted between the angle of normal dogs and those with moderate (75.5 +/- 6.8 degrees, range: 62.8-88.7 degrees) and severe (80.4 +/- 7.7 degrees, range: 64.7-91.7 degrees) left atrial enlargement, as well as between dogs with mild (70.7 +/- 7.2 degrees, range: 57.3-89.9 degrees) and severe enlargement. Using two discriminators, 85.1 degrees and 76.6 degrees, the bifurcation angle had a specificity of 92.6% and 88.9%, respectively, for identifying left atrial enlargement, and a sensitivity of 15.4% and 40.4%. Although significant differences were observed between dogs with normal and increased left atrial size, the large degree of overlap in the range of bifurcation angles and its poor sensitivity make the measurement of this angle of little value for diagnosing left atrial enlargement.

The dose-limiting toxicity of doxorubicin is cardiotoxicosis. The authors of this report hypothesized that by using their institution's adopted guidelines (that involve prescreening echocardiography and electrocardiography), they would detect pre-existing cardiac abnormalities that preclude doxorubicin administration in <10% of dogs. Of 101 dogs, only 6 were excluded from doxorubicin administration based on electrocardiogram abnormalities, with a majority of those arrhythmias classified as ventricular premature contractions. One patient was excluded based on echocardiogram alone due to hypertrophic cardiomyopathy. The incidence of cardiotoxicity in treated dogs was 8% (8/101). Additional pretreatment and ongoing studies are indicated to identify risk factors for cardiotoxicity.

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Pathologic right-sided heart changes are a common echocardiographic finding in patients with pulmonary hypertension (PH). Canines with PH may have right heart pathology documented via echocardiographic color Doppler interrogation including tricuspid valve regurgitation, pulmonic valve insufficiency, elevated pulmonary arterial systolic pressure, elevated pulmonary arterial diastolic pressure, and alterations in ejection profiles. Two-dimensional echocardiographic findings may include right ventricular hypertrophy, interventricular septal flattening, paradoxical interventricular septal motion, pulmonary artery dilation, and potentially abnormal left heart dimensions. In veterinary medicine, much confidence is given to the measurement of pulmonary arterial systolic pressure estimated from tricuspid valve regurgitation to grade the severity of PH and monitor its improvement with little emphasis placed on the integration of two-dimensional echocardiographic right and left heart pathology in conjunction with Doppler findings. To the authors’ knowledge, marked improvement and/or resolution of echocardiographic-documented right heart pathology have not been previously reported in the veterinary literature. This case report documents profound echocardiographic improvement of right-sided heart disease in a dog with severe PH.