Tricuspid annular plane systolic excursion (TAPSE) in dogs: reference values and impact of pulmonary hypertension.

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.

Canine and feline caval syndrome.

The caval syndrome is a serious complication of chronic heartworm (Dirofilaria immitis) disease in dogs and cats. The syndrome is characterized by acute anorexia, respiratory distress, weakness, right-sided cardiac murmur, anemia, hemoglobinuria, hepatic and renal dysfunction, signs of forward and backward heart failure, and, possibly, disseminated intravascular coagulation (DIC). Retrograde migration of adult heartworms from the pulmonary arteries to the right ventricle, right atrium, and venae cavae causes disruption of the tricuspid apparatus. Valvular insufficiency, with concurrent pulmonary hypertension, reduces cardiac output thus resulting in forward and backward heart failure. Additionally, red blood cells are traumatized and hemolyzed as they flow through the mass of worms. Therapy consists of supportive care and the removal of the heartworm mass from the right ventricular inflow tract. Caval syndrome in dogs and cats is associated with high mortality rates and generally has a guarded to poor prognosis.

Advances in antiarrhythmic therapy.

The therapy of cardiac arrhythmias in small animals can be confusing and challenging. This article reviews the current concepts of cardiac rhythm, including impulse generation, automaticity, and conduction in normal and diseased cardiac tissues. The mechanisms of arrhythmogenesis (abnormal automaticity and triggered events) and automatic modulation of cardiac arrhythmias are also discussed. Finally, a review of the clinical management of specific cardiac arrhythmias provides the practicing veterinarian with the current concepts of cardiac rhythm control.