Bidirectional flow across a perforate cor triatriatum dexter in a dog with concurrent pulmonary, tricuspid, and mitral valve dysplasia

Percutaneous Balloon Dilation in Two Dogs with Cor Triatriatum Dexter

Percutaneous balloon dilation was performed in a Rhodesian Ridgeback and in an American Staffordshire Terrier affected by cor triatriatum dexter (CTD). Both cases had ascites without jugular venous distension or pleural effusion. In both dogs the CTD presented a perforated membrane but with different morphology: in one case the coronary sinus entered the caudal chamber of the CTD together with the caudal vena cava. In the other case, the coronary sinus communicated with the cranial chamber of the CTD together with the cranial vena cava. Percutaneous balloon dilation of the CTD was successfully performed, and both dogs had uneventful surgery recoveries. At two years of follow-up, the dogs were free from clinical signs and cardiac medication.

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.