Background: Age and heart rate have effects on myocardial velocities as assessed by color tissue Doppler imaging (TDI) in people. A similar phenomenon has been identified when left ventricular velocities are assessed in cats. To date, the effects of age and heart rate on tricuspid annular velocities of cats have not been assessed.Objectives: This study was designed to determine the relationships between age and heart rate and tricuspid annular velocities in cats as assessed by 2-dimensional (2D) color TDI.Animals: Fifty healthy nonsedated cats with age range from 3 months to 19 years old were studied. Methods: Tricuspid annular velocities were obtained with 2D color TDI. Effects of age and heart rate on tricuspid annular velocities were evaluated by simple linear regression. The strength of the linear relationship was determined by using coefficient of determination (R