Left Atrial Enlargement in Cats

This study evaluated cats with known or suspected heart disease using diagnostic techniques available in private practices. Of 151 cats, 103 had heart disease, 19 had respiratory disease, and 29 were controls. All cats had a full history, physical examination, blood pressure, ECG, and echocardiographic examination. Of the cats with cardiac disease, 77 had primary acquired disease, 16 had secondary heart disease, and 10 had congenital disease. For data analysis, cats were divided into 3 groups: group 1, no heart disease (normal and respiratory disease cats); group 2, heart disease with no clinical signs of heart failure; and group 3, heart disease with clinical signs of failure. Significant difference in prevalence of murmurs was noted, with 50%, 25%, and 65% of normal cats, cats with respiratory disease, and cats with primary acquired disease having murmurs, respectively. Arrhythmia was noted in 26% of all cats, with significant differences among groups; group 3 had the highest percentage (48%). Group 3 also had the highest prevalence of gallop sounds and a significantly lower median heart rate. Prevalence of coughing was highest in the respiratory group (63%), whereas only 8 cats with cardiac disease coughed. Echocardiographic [measurement of left atrial diameter was significantly different among the groups, with medians of 12, 15, and 20 mm in groups 1, 2, and 3, respectively. A left atrial diameter >16.5 mm may help differentiate heart failure from respiratory disease.

CommentaryThis study described important findings clinicians likely see in cats with cardiac disease and CHF. This population of cats typically does not cough, may or may not have a murmur, and may have a depressed heart rate. A brief echocardiographic evaluation of the left atrial size can provide highly sensitive and specific information about a cat with heart failure. Recently, NT-proBNP (a cardiac blood-based biomarker) analysis has been shown to accurately discriminate between cats with respiratory disease and cats with CHF.1 Elevated NT-proBNP concentration in a cat with dyspnea can help diagnose CHF when the cause of dyspnea is unclear and difficult to determine.—Heidi Kellihan, DVM, DACVIM (Cardiology)

SourceClinical signs and left atrial size in cats with cardiovascular disease in general practice. Smith S, Dukes-McEwan J. J SMALL ANIM PRACT 53:27-33, 2012