Quantification of Feline Myocardial Velocities by Tissue Doppler Imaging
World Small Animal Veterinary Association World Congress Proceedings, 2009
A. Pellegrino; R.J. Yamato; G.G. Pereira; A.G.T. Daniel; V.M.C. Oliveira; M.H.M.A. Larsson
Universidade de São Paulo, São Paulo, Brazil

Tissue Doppler Imaging (TDI) is a new echocardiographic method that allows analysis of velocity from myocardial motion along the cardiac cycle. This study evaluated some aspects of left ventricular myocardial function of normal cats by TDI. TDI examinations were performed in ten healthy cats (5 females and 5 males) without breed definition. Measurements were made in basal, middle and apex segments of the left ventricular free wall (LVFW) and of the interventricular septum (IVS) (longitudinal velocities); and in the endocardium and epicardium of LVFW (radial velocities). Mean weight was 4.80 ± 1.27 kg and age 6.8±4.57 years with no significant difference between females and males. The longitudinal velocities values (cm/s) at basal, middle and apical of LVFW were: Sm = 6.42±2.31, 5.99±2.19 and 4.53±1.75; Em = 5.64±2.86, 4.26±1.72 and 3.78±1.59; Am = 5.09±2.15, 3.98±2.24 and 2.88±1.44; Em/Am = 1.49±1.14, 1.66±1.36 and 1.57±0.81. At basal, middle and apical segments of the IVS, the velocities (cm/s) were: Sm = 6.42±1.85, 5.01±2.05 and 4.23±2.23; Em = 2.89±1.66, 2.80±1.47 and 2.00±0.67; Am = 6.68±1.52, 5.72±2.10 and 3.32±2.49; Em/Am = 0.48±0.37, 0.70±0.83 e 0.95±0.75. The values obtained from radial motion of LVFW of endocardium (cm/s) were: Sm = 6.00±1.76, Em = 6.41±2.91 and Am = 5.21±2.22; and Em/Am = 1.32±0.56; and of epicardium were: Sm = 5.04±1.70, Em = 4.78±1.52 and Am = 3.79±1.63; Em/Am = 1.44±0,68. All velocity profiles included a positive systolic wave (S) and two diastolic negative waves, one in early diastole (E) and other (A) in the end (atrial contraction); or only one negative diastolic wave (EA) when diastolic waves were summated owing to rapid heart rate. They also included two phases, one between S and E, and another between A and S, corresponding to isovolumetric relaxation and isovolumetric contraction, respectively. The myocardial velocities decreased from the endocardium to the epicardium (circumferential) and from the base to the apex (longitudinal). Based on results, it was concluded that: myocardial wall moves in the opposite direction in systole and diastole; increased heart rate causes fusion of myocardial Em and Am, making its interpretation difficult; there are two types of intrinsic myocardial motion, radial and longitudinal; and TDI is an alternative tool that can assist in early detection of myocardial abnormalities.

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A. Pellegrino
Universidade de São Paulo
São Paulo, Brazil

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