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.