Radiographic and Echocardiographic Assessment of Left Atrial Size in 100 Cats With Acute Left‐sided Congestive Heart Failure

Abstract

The aims of this study were to evaluate left atrial size in cats with acute left-sided congestive heart failure. We hypothesized that left atrial size as determined by thoracic radiography can be normal in cats with acute left-sided congestive heart failure. One hundred cats with acute left-sided congestive heart failure in which thoracic radiography and echocardiography were performed within 12 h were identified. Left atrial size was evaluated using right lateral and ventrodorsal radiographs. Measurements were compared to two-dimensional echocardiographic variables of left atrial size and left ventricular size. On echocardiography, left atrial enlargement was observed in 96% cats (subjective assessment) whereas maximum left atrial dimension was increased (>15.7 mm) in 93% cats. On radiographs left atrial enlargement (subjective assessment) was found in 48% (lateral view), 53% (ventrodorsal view), and 64% (any view) of cats whereas left atrial enlargement was absent in 36% of cats in both views. Agreement between both methods of left atrial size estimation was poor (Cohen's kappa 0.17). Receiver operating characteristic curve analysis identified a maximum echocardiographic left atrial dimension of approximately 20 mm as the best compromise (Youden index) between sensitivity and specificity in the prediction of radiographic left atrial enlargement. Left atrial enlargement as assessed by thoracic radiography may be absent in a clinically relevant number of cats with congestive heart failure. Therefore, normal left atrial size on thoracic radiographs does not rule out presence of left-sided congestive heart failure in cats with clinical signs of respiratory distress.

Distribution of alveolar‐interstitial syndrome in dogs and cats with respiratory distress as assessed by lung ultrasound versus thoracic radiographs

“…Surprisingly little primary literature exists to document distribution of pulmonary disease on TXR. Studies that do report TXR findings with specific diseases often list only the predominant pulmonary pattern (alveolar, interstitial, or bronchial) or state that patients had “pulmonary infiltrates consistent with” a particular diagnosis, but fail to report the actual distribution of pulmonary disease (by lobe, quadrant, or another spatial definition). Furthermore, to the authors’ knowledge, no previous studies have compared distribution of AIS among patients with different diseases to see whether particular patterns of distribution of AIS are statistically overrepresented in certain disease types.…”

“…Some studies use general descriptors such as “diffuse,” “multifocal,” and “focal,” but do not specify exact locations of pathology; some studies classify pathology as “caudal/caudodorsal” versus “cranial,” but do not clarify laterality . Some studies use the descriptor “hilar” or “perihilar” but also discuss pathology by individual lung lobes, of which the perihilar area must be a part . Given the lack of standardization, investigators must either choose to describe TXR appearance of pulmonary pathology in individual lung lobes (and list all permutations of patterns of lobe involvement) or use a system based on larger spatial areas (such as lung quadrants).…”

ACVIM consensus statement guidelines for the classification, diagnosis, and management of cardiomyopathies in cats

“…Cardiomyopathy might be suspected when severe cardiomegaly is present radiographically, when a left auricular bulge is present on dorsoventral/ventrodorsal radiographic views, or both . Thoracic radiography is insensitive for identification of mild or moderate cardiac changes associated with cardiomyopathy, and in some cats the cardiac silhouette may appear normal even when disease is severe enough to cause CHF . Furthermore, it is difficult to identify the cardiomyopathy phenotype from the shape of the cardiac silhouette, and the classic “valentine‐shaped” heart is not specific for HCM, as previously thought .…”

Echocardiography

“…255 long-axis plane used to measure the LA (or alternatively, obtained from conventional M-mode echocardiography). The auricle becomes especially prominent in cats with LA dilatation.…”

“…105,125,135,232,233,235,236,238,239,243,[246][247][248]250,[252][253][254][255] Quantitation of LA mass is far more difficult because the atrial walls are so thin. 105,125,135,232,233,235,236,238,239,243,[246][247][248]250,[252][253][254][255] Quantitation of LA mass is far more difficult because the atrial walls are so thin.…”