ECHOCARDIOGRAPHIC AND DOPPLER DIAGNOSIS: FIRST CASE OF ATRIAL SEPTAL ANEURYSM IN A CAT

Acquired left-to-right shunting through a valve-incompetent foramen ovale in a cat with hypertrophic cardiomyopathy and congestive heart failure

Case summary

An 8-year-old spayed female domestic shorthair cat was presented for a recheck evaluation of hypertrophic cardiomyopathy and chronic kidney disease. Three years prior to presentation, the patient was diagnosed with obstructive hypertrophic cardiomyopathy and started on atenolol. The left ventricular outflow tract obstruction subsequently resolved. Biochemical analysis a week prior to presentation demonstrated severe azotemia. Transthoracic echocardiograph revealed pericardial effusion, pleural effusion, severe left ventricular concentric hypertrophy, severe left atrial enlargement and continuous left-to-right flow through the interatrial septum near the fossa ovalis. The patient was euthanized owing to poor prognosis, and gross examination at necropsy revealed a valve-incompetent patent foramen ovale secondary to severe left atrial dilation.

Relevance and novel information

To our knowledge, this is the first report of an acquired left-to-right shunt through a valve-incompetent foramen ovale in a cat with hypertrophic cardiomyopathy. Severe left atrial dilation was suspected to cause interatrial shunting through the valve-incompetent foramen ovale, and this finding may be relevant to echocardiographic evaluations in other cats.

Sequential segmental classification of feline congenital heart disease

Feline congenital heart disease is less commonly encountered in veterinary medicine than acquired feline heart diseases such as cardiomyopathy. Understanding the wide spectrum of congenital cardiovascular disease demands a familiarity with a variety of lesions, occurring both in isolation and in combination, along with an appreciation of complex nomenclature and variable classification schemes. This review begins with an overview of congenital heart disease in the cat, including proposed etiologies and prevalence, examination approaches, and principles of therapy. Specific congenital defects are presented and organized by a sequential segmental classification with respect to their morphologic lesions. Highlights of diagnosis, treatment options, and prognosis are offered. It is hoped that this review will provide a framework for approaching congenital heart disease in the cat, and more broadly in other animal species based on the sequential segmental approach, which represents an adaptation of the common methodology used in children and adults with congenital heart disease.