Reversible right-sided congestive heart failure secondary to primary hyperaldosteronism in a cat

A 10-year-old male castrated Somali cat presented with neurologic signs, severe systemic hypertension, and hypokalemia. Abdominal ultrasonography demonstrated a left adrenal mass, and the serum aldosterone concentration was increased. Computed tomography and follow-up diagnostic testing confirmed a left adrenal mass consistent with functional adenocarcinoma; additional findings included chronic airway and parenchymal disease. Transthoracic echocardiography revealed biatrial enlargement, with abdominal and pericardial effusion, consistent with right-sided congestive heart failure. The cat was treated for congestive heart failure and adrenalectomy was performed. Cardiac structure and function returned to normal within 6 months postoperatively. This report highlights a case of reversible congestive heart failure secondary to primary hyperaldosteronism.