AGE-RELATED-CHANGES IN THE FELINE CARDIAC SILHOUETTE

An exaggerated ''horizontal'' alignment of the heart (increased sterna l contact) and tortuous, redundant aorta are often seen on thoracic ra diographs of older cats. Eighty-five cats, divided into 3 age groups [ young (6-15 months), middle aged (3-7 years), old (10-17 years)], were determined to be normal on history, auscultation, ECG, and echocardio gram. Lateral and VD thoracic radiographs were examined and measured f or evidence of these changes. Forty percent of cats 10 years or older were found to have the horizontal cardiac alignment, and 28 % had the redundant aorta. These changes were not seen in Groups 1 and 2 of youn ger and middle aged cats. The angle between the heart and sternum in G roup 3 (old) cats was significantly smaller than the same angle in you nger cats. Systemic hypertension and hyperthyroidism, possible patholo gic causes for this variation, were unlikely related to the cardiovasc ular changes due to the large number of older cats with this change, a nd lack of evidence of left ventricular hypertrophy.