RESUMO
Pulmonary transit time (PTT) normalized to heart rate (nPTT) is a measure of the pulmonary blood volume (PBV) to stroke volume ratio (PBV/SV). It is an index of cardiac performance. To determine the effect of compensated mitral regurgitation (CMR) and decompensated mitral regurgitation (DMR) caused by valvular endocardiosis on the index nPTT, we measured nPTT by first-pass radionuclide angiocardiography and ECG in 13 normal dogs, 18 dogs with CMR, and 13 dogs with DMR. PTT was measured as time between onset of appearance of activity at the pulmonary trunk and the left atrium. In the normal dogs, the relationship between PTT and mean R-R interval (mRR) was PTT = 4.08 x mRR + 0.15 (R2 = 0.71). Normal nPTT was 4.4 +/- 0.6 (SD) (range. 3.6-5.3). in CMR, 6.3 +/- 1.6 (SD) (range, 4.0-9.7). and in DMR, 11.9 +/- 3.4 (SD) (range, 8.0-18.8). The differences among all groups were significant. Heart rates were 110 +/- 22 bpm in normal dogs, 111 +/- 20 in dogs with CMR, and 144 +/- 18 in dogs with DMR (P < .001 for difference between DMR group and normal and CMR groups). Increased nPTT in CMR indicates preclinical heart pump dysfunction. Heart rate-normalized pulmonary transit times may be a useful index of heart function in mitral regurgitation.
Assuntos
Doenças do Cão/fisiopatologia , Pulmão/fisiopatologia , Insuficiência da Valva Mitral/fisiopatologia , Circulação Pulmonar/fisiologia , Angiocardiografia/veterinária , Animais , Função Atrial/fisiologia , Doenças do Cão/diagnóstico por imagem , Cães , Ecocardiografia/veterinária , Átrios do Coração/diagnóstico por imagem , Frequência Cardíaca , Ventrículos do Coração/diagnóstico por imagem , Pulmão/diagnóstico por imagem , Insuficiência da Valva Mitral/diagnóstico por imagem , Angiografia Cintilográfica/veterinária , Volume Sistólico/fisiologia , Função VentricularRESUMO
First-pass radionuclide angiography of the terminal aorta was performed in 3 normal horses and a 6-year-old Standardbred intact male with aortoiliac thromboembolism. Thromboembolism caused chronic bilateral hind limb lameness, more severe in the right hind limb, was detected by rectal examination, and confirmed using transrectal ultrasonography. Using 99mTc-HDP, first-pass radionuclide angiography was combined with hind limb and pelvis bone (delayed) scintigraphy and revealed marked reduction in blood flow through both external iliac arteries and absence of blood flow in the internal iliac arteries. Quantitative analysis showed a decreased activity in the right iliac vessels in the clinic patient consistent with reduced blood flow when compared to control horses. First-pass radionuclide angiography provided a method to obtain diagnostic images of the terminal aorta and branches and a method to diagnose aortoiliac thromboembolism in the horse.
