Congenital Cardiac Defects in a Cat

Patient Information:

Age: 4 years old

Species: Feline

Breed: DSH

Gender: Male

History:

Feline patient from an animal rescue. Clinically asymptomatic for heart disease. A grade 3/6 systolic murmur was detected on auscultation. Pro-BNP was elevated at 436pmol/L (N - <100).

Echocardiogram interpretation:

Complex congenital heart disease. There appeared to be a second chamber in the dorsal left atrium which could be a supravalvular mitral stenosis or a cor triatriatum sinister. The right ventricle had a very abnormal papillary muscle/ridge that seemed to divide the right ventricle into a high pressure proximal chamber and a lower pressure distal chamber consistent with a double chamber right ventricle. There was also concern that a small VSD was present.

Diagnosis:

Double chamber right ventricle, CTD/supravalvular mitral stenosis with possible VSD.

Image 1. Right parasternal long-axis view showing the normal left ventricle (LV) and atrium (LA) and the double chamber right ventricle (RV1 and RV2).

Image 2. Right parasternal short-axis view showing the normal left ventricle (LV) and the double chamber right ventricle (RV1 and RV2).

Image 3. Right parasternal long-axis view showing the 2nd chamber dorsal to the left atrium and suspected supravalvular mitral stenosis or cor triatriatum sinister (arrow).

Monitoring and therapeutic recommendations:

The patient had reached 4 years of age with no clinical signs and RV hypertrophy. No treatment was clearly indicated but beta blockers such as atenolol or propranolol could be considered. While balloon dilation of the RV obstruction could be attempted, it is very muscular so unlikely to respond. Referral to a board-certified cardiologist for full evaluation and a repeat echocardiogram in 6 months were recommended.