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  • Author or Editor: Audrey Nicolle x
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Abstract

Objective—To describe and analyze the left ventricular free wall (LVFW) radial and longitudinal motions in a population of healthy Maine Coon cats by use of quantitative 2-dimensional color tissue Doppler imaging (TDI).

Animals—23 healthy young Maine Coon cats (mean ± SD: age, 2.1 ± 0.9 years; weight, 5.0 ± 1.0 kg).

Procedure—TDI was performed by the same trained observer (VC) on all cats. Radial LVFW velocities were recorded in endocardial and epicardial LVFW segments, and longitudinal velocities were recorded in the mitral annulus and in basal and apical LVFW segments. Isovolumic contraction and relaxation times were calculated in each myocardial segment, and the coefficients of variation (CVs; %) were determined for each TDI parameter.

Results—LVFW velocities were significantly higher in the endocardial layers than in the epicardial layers and also significantly higher in the basal than in the apical segments. Annular velocities were significantly higher than basal myocardial velocities in systole and early diastole. Coefficient of variation values were lower for radial velocities, particularly in systole, and were also lower for time intervals (16% to 22%) than for myocardial velocities (19% to 62%).

Conclusions and Clinical Relevance—Because Maine Coon cats are predisposed to an inherited hypertrophic cardiomyopathy, which is a common cause of death in this breed, TDI could provide a useful tool for early detection of the disease. Tissue Doppler imaging indices may complete the conventional analysis of the left ventricular function in Maine Coon cats. However, the usefulness of TDI indices in the early detection of myocardial dysfunction needs to be clarified. (Am J Vet Res 2005;66:1936–1942)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To analyze velocities of the annulus of the left atrioventricular valve and left ventricular free wall (LVFW) in a large population of healthy cats by use of 2-dimensional color tissue Doppler imaging (TDI).

Animals—100 healthy cats (0.3 to 12.0 years old; weighing 1.0 to 8.0 kg) of 6 breeds.

Procedure—Radial myocardial velocities were recorded in an endocardial and epicardial segment, and longitudinal velocities were recorded in 2 LVFW segments (basal and apical) and in the annulus of the left atrioventricular valve.

Results—LVFW velocities were significantly higher in the endocardial than epicardial layers and significantly higher in the basal than apical segments. For systole, early diastole, and late diastole, mean ± SD radial myocardial velocity gradient (MVG), which was defined as the difference between endocardial and epicardial velocities, was 2.2 ± 0.7, 3.3 ± 1.3, and 1.8 ± 0.7 cm/s, respectively, and longitudinal MVG, which was defined as the difference between basal and apical velocities, was 2.7 ± 0.8, 3.1 ± 1.4, and 2.1 ± 0.9 cm/s, respectively. A breed effect was documented for several TDI variables; therefore, reference intervals for the TDI variables were determined for the 2 predominant breeds represented (Maine Coon and domestic shorthair cats).

Conclusions and Clinical Relevance—LVFW velocities in healthy cats decrease from the endocardium to the epicardium and from the base to apex, thus defining radial and longitudinal MVG. These indices could complement conventional analysis of left ventricular function and contribute to the early accurate detection of cardiomyopathy in cats.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine left ventricular free wall (LVFW) radial and longitudinal myocardial contraction velocities in healthy dogs via quantitative 2-dimensional color tissue Doppler imaging (TDI).

Animals—100 dogs.

Procedure—TDI was used by a single trained observer to measure radial and longitudinal myocardial movement in the LVFW. Radial myocardial velocities were recorded in segments in the endocardial and epicardial layers of the LVFW, and longitudinal velocities were recorded in segments at 3 levels (basal, middle, apical) of the LVFW.

Results—LVFW velocities were higher in the endocardial layers than in the epicardial layers. Left ventricular free wall velocities were higher in the basal segments than in the middle and apical segments. Radial myocardial velocity gradients, defined as the difference between endocardial and epicardial velocities, were (mean ± SD) 2.5 ± 0.8 cm/s, 3.8 ± 1.5 cm/s, and 2.3 ± 0.9 cm/s in systole, early diastole, and late diastole, respectively. Longitudinal myocardial velocity gradients, defined as the difference between basal and apical velocities, were 5.9 ± 2.2 cm/s, 6.9 ± 2.5 cm/s, and 4.9 ± 1.7 cm/s in systole, early diastole, and late diastole, respectively. A breed effect was detected for several systolic and diastolic TDI variables. In all segments, systolic velocities were independent of fractional shortening.

Conclusions and Clinical Relevance—LVFW myocardial velocities decreased from the endocardium to the epicardium and from base to apex, thus revealing intramyocardial radial and longitudinal velocity gradients. These indices could enhance conventional echocardiographic analysis of left ventricular function in dogs. Breed-specific reference intervals should be defined. (Am J Vet Res 2005;66:953–961)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine left ventricular free wall (LVFW) motions and assess their intra- and interday variability via tissue Doppler imaging (TDI) in healthy awake and anesthetized dogs.

Animals—6 healthy adult Beagles.

Procedure—In the first part of the study, 72 TDI examinations (36 radial and 36 longitudinal) were performed by the same observer on 4 days during a 2-week period in all dogs. In the second part, 3 dogs were anesthetized with isoflurane and vecuronium. Two measurements of each TDI parameter were made on 2 consecutive cardiac cycles when ventilation was transiently stopped. The TDI parameters included maximal systolic, early, and late diastolic LVFW velocities.

Results—The LVFW velocities were significantly higher in the endocardial than in the epicardial layers and also significantly higher in the basal than in the midsegments in systole, late diastole, and early diastole. The intraday coefficients of variation (CVs) for systole were 16.4% and 22%, and the interday CV values were 11.2% and 16.4% in the endocardial and epicardial layers, respectively. Isoflurane anesthesia significantly improved the intraday CV but induced a decrease in LVFW velocities, except late diastolic in endocardial layers and early diastolic in epicardial layers.

Conclusions and Clinical Relevance—Left ventricular motion can be adequately quantified in dogs and can provide new noninvasive indices of myocardial function. General anesthesia improved repeatability of the procedure but cannot be recommended because it induces a decrease in myocardial velocities. (Am J Vet Res 2004;65:909–915)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To measure the radial and longitudinal velocities of several myocardial segments of the left ventricular wall by use of tissue Doppler imaging (TDI) in healthy cats and determine the repeatability and reproducibility of the technique.

Animals—6 healthy cats.

Procedure—72 TDI examinations were performed on 4 days by the same trained observer. Radial parameters included left endocardial and epicardial myocardial velocities. Longitudinal parameters included left basal, middle, and apical myocardial velocities.

Results—All velocity profiles had 1 positive systolic wave (S) and 2 negative diastolic waves (E and A). Myocardial velocities were higher in the endocardial than epicardial segments during the entire cardiac cycle (systolic wave S, 4.4 ± 0.82 and 1.9 ± 0.55; diastolic wave E, 9.7 ± 1.70 and 2.2 ± 0.74; and diastolic wave A, 5.1 ± 1.56 and 1.4 ± 0.76, respectively). Velocities were also higher in the basal than in the apical segments (systolic wave S, 4.7 ± 0.76 and 0.2 ± 0.11; diastolic wave E, 9.7 ± 1.36 and 0.5 ± 0.17; and diastolic wave A, 3.7 ± 1.51 and 0.2 ± 0.13, respectively). The lowest within-day and between-day coefficients of variation were observed in endocardial segments (8.2% and 6.5% for systolic wave S and diastolic wave E, respectively) and in the basal segment in protodiastole (5.5%).

Conclusions and Clinical Relevance—Repeatability and reproducibility of TDI were adequate for measurement of longitudinal and radial left ventricular motion in healthy awake cats. Validation of TDI is a prerequisite before this new technique can be recommended for clinical use. ( Am J Vet Res 2004; 65:566–572)

Full access
in American Journal of Veterinary Research