Changes in radial and longitudinal left ventricular (LV) function were investigated in beagles with iatrogenic hypercortisolism. A total of 11 normal dogs were used, and 2 mg/kg prednisone was administered per oral q12 h for 28 days to 7 out of 11 dogs to induce iatrogenic hypercortisolism. Body weight, blood pressure, conventional echocardiography and tissue Doppler imaging (TDI) of normal and iatrogenic hypercortisolism groups were conducted. The myocardial wall velocity of the LV was measured using color TDI and myocardial deformation was determined by the strain and strain rate. Conventional echocardiography revealed that the diastolic LV free wall and interventricular septum in the hypercortisolism group were thickened relative to those in the normal group. The peak early diastolic myocardial velocity and early to late diastolic myocardial velocity ratio of TDI in the hypercortisolism group were significantly lower than those in the normal group. The strain values in the hypercortisolism group were significantly lower than those in the normal group, particularly for longitudinal wall motion. The lower values of myocardium from TDI and strain imaging could be used to investigate subclinical LV systolic and diastolic dysfunction in dogs with the iatrogenic hypercortisolism.
Animals ; Cushing Syndrome/etiology/*veterinary ; Dogs ; Echocardiography, Doppler/*veterinary ; Heart Ventricles/*ultrasonography ; Iatrogenic Disease/veterinary ; Male ; Reproducibility of Results ; *Ventricular Function, Left

This study was conducted to evaluate the usefulness of coronary arterial profiles from normal dogs (11 animals) and canines (six dogs) with experimental myocardial infarction (MI) induced by ligation of the left coronary artery (LCA). Blood velocity of the LCA and right coronary artery (RCA) were evaluated following transthoracic pulsed-wave Doppler echocardiography. The LCA was observed as an infundibular shape, located adjacent to the sinus of Valsalva. The RCA appeared as a tubular structure located 12 o'clock relative to the aorta. In normal dogs, the LCA and RCA mean peak diastolic velocities were 20.84 +/- 3.24 and 19.47 +/- 2.67 cm/sec, respectively. The LCA and RCA mean diastolic deceleration times were 0.91 +/- 0.14 sec and 1.13 +/- 0.20 sec, respectively. In dogs with MI, the LCA had significantly (p < 0.01) lower peak velocities (14.82 +/- 1.61 cm/sec) than the RCA (31.61 +/- 2.34 cm/sec). The RCA had a significantly (p < 0.01) rapid diastolic deceleration time (0.71 +/- 0.06 sec) than that found in the LCA (1.02 +/- 0.22 sec) of MI dogs. In conclusion, these profiles may serve as a differential factor for evaluating cardiomyopathy in dogs.
Animals ; Blood Flow Velocity/*veterinary ; Coronary Vessels/surgery/*ultrasonography ; Dog Diseases/*diagnosis ; Dogs/*physiology ; Echocardiography, Doppler, Pulsed/standards/*veterinary ; Female ; Male ; Myocardial Infarction/diagnosis/*veterinary

The present study was performed to determine the accuracy and reproducibility of calculating the mitral regurgitant orifice area with the proximal isovelocity surface area (PISA) method in dogs with experimental mitral regurgitation and in canine patients with chronic mitral insufficiency and to evaluate the effect of general anesthesia on mitral regurgitation. Eight adult, Beagle dogs for experimental mitral regurgitation and 11 small breed dogs with spontaneous mitral regurgitation were used. In 8 Beagle dogs, mild mitral regurgitation was created by disrupting mitral chordae or leaflets. Effective regurgitant orifice (ERO) area was measured by the PISA method and compared with the measurements simultaneously obtained by quantitative Doppler echocardiography 4 weeks after creation of mitral regurgitation. The same procedure was performed in 11 patients with isolated mitral regurgitation and in 8 Beagle dogs under two different protocols of general anesthesia. ERO and regurgitant stroke volume (RSV) by the PISA method correlated well with values by the quantitative Doppler technique with a small error in experimental dogs (r = 0.914 and r = 0.839) and 11 patients (r = 0.990 and r = 0.996). The isoflurane anesthetic echocardiography demonstrated a significant decrease of RSV, and there was no significant change in fractional shortening (FS), ERO area, LV end-diastolic and LV end-systolic volume. ERO area showed increasing tendency after ketamine-xylazine administration, but not statistically significant. RSV, LV end-systolic and LV end-diastolic volume increased significantly (p < 0.01), whereas FS significantly decreased (p < 0.01). The PISA method is accurate and reproducible in experimental mitral regurgitation model and in a clinical setting. ERO area is considered and preferred as a hemodynamic-nondependent factor than other traditional measurements.
Anesthesia, Rectal ; Animals ; Body Surface Potential Mapping/*veterinary ; Chordae Tendineae/physiopathology/surgery ; Dog Diseases/diagnosis/*physiopathology ; Dogs ; Echocardiography, Doppler/veterinary ; Electrocardiography/veterinary ; Mitral Valve/*physiopathology ; Mitral Valve Insufficiency/diagnosis/physiopathology/*veterinary