A simple algorithm allows triaging of dogs with mitral valve disease into cardiac or noncardiac causes of dyspnea

Objective To create a simple algorithm for diagnosis of congestive heart failure (CHF) in dogs with myxomatous mitral valve disease (MMVD). Methods Data were collected between November 2, 2015, and December 7, 2017, from dogs presented to investigators after a tentative diagnosis of CHF by first-opinion clinicians. Investigators completed a data-submission form and provided a final diagnosis of CHF or subclinical MMVD. Data included each of the 8 variables of the original algorithm. Variables that did not change diagnostic accuracy were removed from the model. Results 120 dogs were included: 46 with CHF and 74 with subclinical cardiac disease and an alternate diagnosis for clinical signs; 82 dogs (36 with CHF) were referred for coughing. All dogs with CHF had loud or palpable murmurs, as did 59 without CHF. Forty-five dogs with CHF and 26 without CHF lacked sinus arrhythmia. All nonpanting dogs with CHF and 7 of 56 without CHF had tachypnea or dyspnea. All dogs with CHF had moderate-to-severe left atrial enlargement versus 25 of 35 dogs without CHF. Examined in series, these 4 variables yielded an algorithm sensitivity of 98% and specificity of 95% for diagnosing CHF. Conclusions Clinicians who are presented with a dog suspected of having CHF secondary to MMVD should be able to determine whether CHF is likely using 3 to 4 simple variables: a loud or palpable murmur, lack of sinus arrhythmia, tachypnea or dyspnea, and at least moderate left atrial enlargement. Clinical Relevance This algorithm might improve first-opinion practitioners’ diagnosis of CHF in dogs with MMVD.