Reversible congestive heart failure associated with diabetes mellitus in two cats

This report describes two cats diagnosed with diabetes mellitus who developed clinical signs consistent with congestive heart failure (CHF). Clinical and echocardiographic findings improved over time with stabilisation and optimisation of glycaemic management. Both cats presented with dyspnoea, hypotension and hypothermia. Thoracic radiographs demonstrated diffuse pulmonary infiltrates. Pleural effusion was identified in one case. Echocardiography revealed left ventricular thickening with left atrial enlargement. Laboratory abnormalities included hyperglycaemia, elevated fructosamine and increased N-terminal pro B-type natriuretic peptide (NT-proBNP) concentrations. After CHF therapy and insulin administration, both cats showed rapid clinical improvement, with NT-proBNP concentrations decreasing into the reference interval and improvement in echocardiographic parameters within weeks. One cat later again showed an increase in myocardial thickness and experienced recurrence of CHF during a period of poor glycaemic control, with subsequent improvement after intensified glycaemic management.

To the authors' knowledge, this is the first report describing cats diagnosed with diabetes mellitus who developed CHF accompanied by increased left ventricular wall thickness and left atrial enlargement on echocardiography, with subsequent improvement after clinical stabilisation and glycaemic management. These cases suggest a potential association between metabolic dysregulation and the occurrence of CHF in cats.