Displasia de valva tricúspide associada a comunicação interatrial em um felino da raça Sphynx

Resumo

Background: Congenital heart diseases are rare in cats, accounting for less than 5% of cardiac cases, with tricuspid valve dysplasia (TVD) and atrial septal defect (ASD) being common types. TVD causes structural valve abnormalities and right heart dilation, while ASD creates abnormal atrial blood flow, enlarging the right heart and pulmonary artery. Diagnosis relies on echocardiography, and treatment includes symptomatic management and ACE inhibitors. Prognosis varies with severity and diagnosis timing. The aim is to report a case of tricuspid valve dysplasia associated with atrial septal defect in a Sphynx cat.

Case: A 60-day-old male Sphynx kitten, and weighing 0.5 kg, was presented with respiratory distress, nasal discharge, epiphora, and decreased appetite. Physical examination revealed dehydration, fever (39.9ºC), and a grade III/VI holosystolic murmur. Blood tests were within normal limits. Thoracic radiographs showed a globoid cardiac silhouette with enlargement of the right heart chambers and pulmonary edema suggestive of bronchopneumonia. Echocardiography diagnosed tricuspid valve dysplasia (TVD) characterized by right atrial and ventricular enlargement and significant tricuspid regurgitation. Contrast echocardiography identified an atrial septal defect. The kitten was treated with furosemide and lisinopril. Follow-up echocardiograms demonstrated progressive reduction and eventual closure of the atrial septal defect, accompanied by improvement in the severity of TVD. After 2 years of clinical and echocardiographic monitoring, the cat remains asymptomatic without signs of heart failure, and ACE inhibitor therapy was discontinued. This case highlights the potential for spontaneous closure of atrial septal defects in feline patients with congenital tricuspid valve dysplasia and the benefits of medical management in such cases.

Discussion: Congenital heart diseases in cats are rare and challenging due to small patient size and frequent lack of symptoms at presentation. In this case, a Sphynx kitten was brought in with hyporexia and diarrhea, without obvious cardiac signs. Tricuspid valve dysplasia (TVD), a rare congenital defect more studied in dogs and humans, is scarcely reported in cats, especially in breeds like Sphynx. Atrial septal defects (ASDs) are common in humans and increasingly recognized in veterinary patients, mainly dogs. Auscultation revealed a grade 3 holosystolic murmur on the right, matching the tricuspid valve location. Radiographs showed right atrial and ventricular enlargement and pulmonary edema, linked to TVD, ASD, and bronchopneumonia. Echocardiography confirmed significant TVD; contrast echo suggested a left-to-right shunt without microbubble passage. Treatment with ACE inhibitors and furosemide led to clinical improvement. After 24 months, echocardiography showed reduction or closure of the atrial defect and decreased tricuspid regurgitation, which is unusual. The initial septal defect might have been a remnant embryonic membrane, as it was not confirmed by microbubble contrast and disappeared over time. Spontaneous closure of small interatrial communications is common. Surgical correction is not feasible in many settings due to cost and technical limitations. The cat remains asymptomatic with regular monitoring and a favorable prognosis. Early diagnosis and treatment improved quality of life, but ongoing surveillance is essential. Given limited feline data, it’s unclear if therapy alone caused defect regression, as spontaneous remission occurs in kittens over months to years.

Keywords: atrioventricular hypertrophy, atrium, cardiology, cat.