Severe left atrial enlargement raises coughing risk in dogs

Abstract

OBJECTIVE: To determine whether congestive heart failure (CHF) or specific degrees of left atrial enlargement increase the probability of coughing in dogs with myxomatous mitral valve disease (MMVD). METHODS: Data from 2 previous studies were examined separately and collectively. Proportions of dogs coughing at each level of left atrial enlargement (none, mild, moderate, and severe) were compared in all dogs regardless of clinical status, in dogs with subclinical disease, and in dogs with CHF. Binomial logistic regression examined whether coughing or left atrial enlargement predicted the presence of coughing. RESULTS: 352 dogs with varying degrees of left atrial enlargement were included from the 2 studies. Only severe left atrial enlargement (left atrial-to-aortic ratio, > 2.29) resulted in an increased probability of coughing in dogs with MMVD. Dogs with lesser degrees of left atrial enlargement had similar probabilities of coughing as dogs without left atrial enlargement. Congestive heart failure was not found to be an independent predictor of coughing. CONCLUSIONS: We found no evidence that CHF contributes to or increases the probability of coughing in dogs with MMVD. Conversely, we found that severe left atrial enlargement does increase this probability, independent of clinical status. CLINICAL RELEVANCE: Clinicians should not include coughing (or absence thereof) when considering whether dogs with MMVD have CHF or not. Instead, other findings (regardless of coughing status) should inform the diagnosis.