Signs and survival of dogs and cats with tetralogy of Fallot

Abstract

OBJECTIVE To characterize the epidemiological, clinical, and echocardiographic features of dogs and cats with tetralogy of Fallot (TOF) and determine their survival times. DESIGN Retrospective case series. ANIMALS 15 dogs and 16 cats with a diagnosis of TOF as determined via echocardiography. PROCEDURES Medical records of dogs and cats were reviewed to extract information on signalment, clinical status at the time of TOF diagnosis, echocardiographic findings, and any outcome data. RESULTS The most common canine breeds were terrier types (n = 7). Most animals (28/31 [90%]) had clinical signs of TOF at the time of diagnosis, including cyanosis (16/31 [52%]). Pulmonic stenosis was characterized by a variable systolic Doppler-derived pressure gradient (median [range], 108 mm Hg [26 to 255 mm Hg]). Most ventricular septal defects were large, with a median (range) ratio of the diameter of the ventricular septal defect to that of the aorta of 0.60 (0.18 to 1.15). Median age at cardiac-related death was 23.4 months, with no significant difference between dogs and cats. Median survival time from TOF diagnosis to cardiac-related death was briefer for animals with no or low-grade heart murmur (3.4 months) than for those with higher-grade heart murmur (16.4 months). After adjustment for age and sex, having a lack of or a low- to mild-grade systolic heart murmur was significantly associated with a briefer survival time. CONCLUSIONS AND CLINICAL RELEVANCE With a few exceptions, cardiac-related death occurred predominantly in young adult dogs and cats with TOF, and most animals had severe clinical signs at the time of TOF diagnosis.