Ecg of the Month. Sinus Rhythm with Complete Heart Block
Jacobs G.J. and Otto C.
J Am Vet Med Assoc, 1988. 193(3): p.316-7.
A 10-year-old castrated male domestic longhair cat with hyperthyroidism was referred for radioactive iodine (131I) treatment. Treatment with methimazole was initiated 1 week before our examination. Serum thyroxine concentration before treatment was 8 ug/dl (normal. 1 to .. ug/dl). A grade III/V holosystolic band-shaped murmur at the left apex and a regular rhythm with variation in the intensity of the first heart sound were auscultated. Prominent Cannon a waves of jugular venous pulse were not observed. Mild cardiomegaly was detected by thoracic radiography, and echocardiography revealed mild left atrial enlargement.