<div>Background: Although cortriatriatumsinister (CTs) represents a well-known and widely described cardiac malformation in humans, its description in the canine population is rare. The aim of this ten-year study is to place on record about the most unusual congenital cardiac malformation, cortriatriatum sinister that was sporadically reported among veterinary patients. 
 
Methods: The dogs were examined clinically, physically and later subjected for chest radiograph and echocardiography to confirm CTs. All were showing regular femoral pulse that was strong and synchronous to the heart beat, pale mucosa, mean systolic arterial blood pressure of 145 mm Hg and with normal hemato-biochemical parameters. Cardiomegaly with increased sternal contact, elevated trachea, pulmonary congestion and engorged caudal vena cava were radiographic findings. 2d-echocardiography revealed a left atrium that was subdivided by a transverse membrane into two distinct compartments, one proximal and one distal, thus confirming the cortriatriatum sinister. 
 
Result: Cor triatriatum sinister (CTs) was diagnosed in 4 dogs with a prevalence of 4.59% amongst those suffering from congenital heart anomalies, that were aged between 5y-7y and the breeds include Boxer, Doberman and Cocker spaniel. All these dogs were presented with similar signs suggestive of heart failure viz., exercise intolerance, dyspnoea at rest, cough that was dry nocturnal type, generalised weakness and syncope. All of these patients were successfully managed with frusemide, benazapril and pimobendan. Hence, it may be concluded that the CTS, a rare congenital cardiac anomaly in dogs should also be included in the differential diagnosis of heart failure, particularly if presented at early life, which also helps to prevent further breeding from such stock.</div>

A Ten Year Retrospective Study on Cor Triatriatum Sinister Associated Heart Failure in Dogs