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.
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
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)
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).
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
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)
Objective—To evaluate the effects of positioning and
number of repeated measurements on intra- and
interobserver variability of echocardiographic measurements
Animals—4 healthy dogs.
Procedure—Each observer performed 24 examinations,
separately assessing each dog 6 nonconsecutive
times (3 times with the dog in lateral recumbency
and 3 with the dog in a standing position).
Variables evaluated included M-mode measurements
of left ventricular end-diastolic and left ventricular endsystolic
diameters, left ventricular free-wall thickness
in diastole and systole, interventricular septal thickness
in diastole and systole, left ventricular shortening
fraction, and 2-dimensional measurements of the
left atrial diameter-to-aortic diameter ratio.
Results—All coefficients of variation (range, 3.4% to
26.6%) were similar between operators and positions
and were < 15% for 27 of 32 values. For both operators,
repeatability of the measurements was better
for left ventricular end-systolic diameter, left ventricular
free-wall thickness in diastole, left ventricular freewall
thickness in systole, and the left atrial diameterto-
aortic diameter in the standing position, and similar
for both positions for shortening fraction and left ventricular
end-diastolic diameter. No effect of cardiac
cycle was observed.
Conclusions and Clinical Relevance—Within-day
variability of conventional echocardiography performed
with the dog in the standing position was at least as
good as that obtained with the dog in lateral recumbency
for most measured variables. Single measurements
of each variable may be sufficient for trained
observers examining dogs that do not have an arrhythmia.
The standing position should be used, particularly
for stressed or dyspneic dogs. (J Am Vet Med Assoc 2005;227:743–747)
Objective—To determine the within-day and between-day variability of regurgitant fraction (RF) assessed by use of the proximal isovelocity surface area (PISA) method in awake dogs with degenerative mitral valve disease (MVD), measure RF in dogs with MVD, and assess the correlation between RF and several clinical and Doppler echocardiographic variables.
Animals—6 MVD-affected dogs with no clinical signs and 67 dogs with MVD of differing severity (International Small Animal Cardiac Health Council [ISACHC] classification).
Procedures—The 6 dogs were used to determine the repeatability and reproducibility of the PISA method, and RF was then assessed in 67 dogs of various ISACHC classes. Mitral valve regurgitation was also assessed from the maximum area of regurgitant jet signal-to-left atrium area (ARJ/LAA) ratio determined via color Doppler echocardiographic mapping.
Results—Within- and between-day coefficients of variation of RF were 8% and 11%, respectively. Regurgitation fraction was significantly correlated with ISACHC classification and heart murmur grade and was higher in ISACHC class III dogs (mean ± SD, 72.8 ± 9.5%) than class II (57.9 ± 20.1%) or I (40.7 ± 19.2%) dogs. Regurgitation fraction and left atriumto-aorta ratio, fractional shortening, systolic pulmonary arterial pressure, and ARJ/LAA ratio were significantly correlated.
Conclusions and Clinical Relevance—Results suggested that RF is a repeatable and reproducible variable for noninvasive quantitative evaluation of mitral valve regurgitation in awake dogs. Regurgitation fraction also correlated well with disease severity. It appears that this Doppler echocardiographic index may be useful in longitudinal studies of MVD in dogs.
Objective—To determine the intra- and interobserver variability of systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) measurements obtained with 2 indirect methods in awake dogs and percentage of successful measurements.
Animals—6 healthy conscious adult dogs.
Procedures—4 observers with different levels of training measured SAP and DAP on 4 days by use of Doppler ultrasonography (DU) and high-definition oscillometry (HDO). The examinations were randomized. Measurements for each technique were recorded 5 consecutive times, and mean values (total, 720 measurements) were used for statistical analysis.
Results—All within- and between-day coefficients of variation (CVs) for SAP were < 15% irrespective of the observer or method (HDO, 3.6% to 14.1%; DU, 4.1% to 12.4%). Conversely, half the CVs for DAP were > 15% with the highest within- and between-day CVs obtained by the least experienced observer by use of DU (19.5% and 25.9%, respectively). All attempts with HDO were successful, whereas DAP could not be measured by use of DU by the least experienced observer in 17% of attempts.
Conclusions and Clinical Relevance—SAP may be assessed in healthy dogs by use of DU and HDO with good repeatability and reproducibility after a short period of training. Conversely, the variability of DAP is higher and longer training is required to assess DAP via DU than via HDO.
Objective—To determine the prevalence of Doppler echocardiography–derived evidence of pulmonary arterial hypertension (DEE-PAH) in dogs with mitral valve disease (MVD) classified according to the International Small Animal Cardiac Health Council (ISACHC) heart failure classification scheme and various echocardiographic and Doppler indices of MVD severity.
Design—Retrospective case series.
Animals—617 dogs examined from 2001 to 2005 with MVD in ISACHC classes I to III.
Procedures—Dogs were examined echocardiographically. Criteria used for systolic and diastolic DEE-PAH were detection of high tricuspid (≥ 2.5 m/s) and telediastolic pulmonic (≥ 2.0 m/s) valvular peak regurgitant jet velocities, respectively, by use of continuous-wave Doppler echocardiography.
Results—86 (13.9%) dogs with MVD had a diagnosis of DEE-PAH. Severity and prevalence of DEE-PAH increased with ISACHC class (3.0%, 16.9%, 26.7%, and 72.2% prevalences for ISACHC classes Ia, Ib, II, and III, respectively). A significant correlation between systolic or diastolic pulmonary arterial pressure and left atrial-to-aortic diameter ratio (LA/Ao) was detected. Doppler echocardiography–derived evidence of pulmonary arterial hypertension was detected in 18 dogs with values of LA/Ao within reference range, all of which had moderate (n = 2 dogs) or severe (16) mitral valve regurgitation on color Doppler imaging.
Conclusions and Clinical Relevance—The prevalence and degree of DEE-PAH were related to the severity of MVD. Changes associated with DEEPAH may be detected in early stages of the disease, but only in dogs with severe mitral valve regurgitation.