Association of Age and Heart Rate with Pulsed‐Wave Doppler Measurements in Healthy, Nonsedated Cats

Abstract

Associations of age and heart rate with blood flow velocities and durations assessed by pulsed-wave (PW) Doppler echocardiography in cats are incompletely understood. To determine the effects of age and heart rate on blood flow velocities and durations of cardiac events obtained by PW Doppler echocardiography in healthy, nonsedated cats. A convenience sample of 87 healthy, nonsedated cats aged 3 months to 19 years. Prospective, observational study. PW Doppler measurements were obtained by echocardiography. Association of age and heart rate with PW Doppler values was evaluated by simple and multiple linear regressions and ANCOVA. Significant weak positive relationships were found between age and isovolumic relaxation time (IVRT) (R2= 0.18; P< or = .001), and between age and duration of pulmonary venous retrograde flow (R2= 0.07; P= .041). There was a significant weak negative relationship between age and transmitral peak early diastolic velocity (R2= 0.19; P< or = .001). Age and heart rate were significantly related to pulmonary venous peak systolic velocity (R2= 0.13; P= .008). Heart rate affected transmitral peak late diastolic velocity (R2= 0.11; P= .006). After adjusting for heart rate effect, the PW Doppler variables that were significantly different between age groups were transmitral peak early diastolic velocity (P< or = .001), duration of transmitral late diastolic flow (P< or = .001), IVRT (P< or = .001), and the ratio of duration of transmitral late diastolic flow to duration of pulmonary venous retrograde flow (P= .029). The association of several PW Doppler-derived variables and age and heart rate is weak and not clinically important.