Echocardiographic diagnosis of interventricular septum defect with Eisenmenger syndrome in an adult dog - case report

Interventricular septal defect (IVSD) is a congenital heart disease characterized by communication or non-closure of the interventricular septum in the embryonic or postnatal period, causing a failure in the separation between the systemic and pulmonary circulation. The severity of the hemodynamic consequences depends on the extent of the defect and the magnitude of the flow through it. Blood flow commonly occurs from left to right, because systemic vascular resistance is greater than pulmonary resistance. This report describes the echocardiographic findings in a 4-year-old male Poodle treated at the Veterinary Hospital with a history of exercise intolerance, cyanosis and episodes of syncope. On echocardiography, perimembranous IVSD was diagnosed with atrial and right ventricular dilatation, discontinuity of the interventricular septum in the subaortic region measuring approximately 5 mm. In the Doppler evaluation, reverse turbulent flow was evidenced, characterizing shunt from right to left (Eisenmenger syndrome). Despite preserved systolic function, abnormal relaxation was observed. Doppler echocardiography was a fundamental complementary imaging test for the diagnosis of this congenital heart disease since its suspicion is not commonly raised in adult patients. Doppler echocardiography allowed us to identify the defect, define its size and extension, determine the direction of blood flow as well as its hemodynamic consequences.