An at least 6 month old, castrated male, Siamese cat was presented to the Cardiology Service at Cornell University Hospital for Animals as a referral for severe congestive heart failure. The patient developed a progressive cough of a month duration and was also tachypneic. Pertinent medical history included the following; recent capture as a stray two months prior to referral, recent neutering, administration of Drontal plus, auscultation of a heart murmur, abnormal thoracic radiographs and NT-pro-BNP SNAP, as well as initiation of diuretics and ace inhibitors. At presentation, the patient was bright, alert and responsive with pink mucous membranes, a capillary refill time ofless than two seconds, severe wheezing, marked tachypnea, and normal heart sounds. The patient was placed in oxygen and pulse oximetry revealed adequate oxygenation. This paper will overview ways to differentiate cardiovascular disease from respiratory disease in the cat and review the lungworm Aelurostrongylus abstrusus.