Atrioventricular septal defects: Natural history, echocardiographic, electrocardiographic, and radiographic findings in 26 cats

ObjectivesTo evaluate signalment, echocardiographic, electrocardiographic, and radiographic findings as well as natural history in a group of cats with atrioventricular septal defects (AVSD).Animals26 client owned cats.MethodsMedical records were reviewed retrospectively for signalment, morphologic type of AVSD, presence of concurrent congenital heart disease (ConcCHD), diagnostic findings, and natural history.ResultsSeventeen cats had an isolated AVSD; 13/17 had a partial and 4/17 had a complete AVSD. Double outlet right atrium (DORA) was diagnosed in 4/17 cats. Of those with a partial AVSD, 7/13 had an atrial communication while 6/13 had a ventricular communication. Congestive heart failure (CHF) developed in 5/17 cats; all 3 cats diagnosed with a DORA not lost to follow-up developed pulmonary edema. Sudden death was documented in 4/17 (23.5%). The 5 year survival was 53.0% (9/17). Concurrent congenital heart disease was identified in 9/26 cats with 7/9 having a conotruncal abnormality. Electrocardiography was performed in 14 cats with 11/14 diagnosed with a conduction disturbance.ConclusionsOverall the echocardiographic and electrocardiographic findings with AVSD are similar to that seen in humans. Cats may have a higher prevalence than humans of partial AVSD with ventricular communication only as well as a higher prevalence of DORA. Cats with an AVSD have an overall guarded prognosis although some can live for a protracted time.