A six‐mоnth‐оld Dаlmаtiаn named Bailey is brоught to the clinic with lethargy. The owner states that Bailey has been resistant to going for walks and begins panting after walking around the yard. Bailey has tachycardia and a delayed CRT. MM are cyanotic and a Grade IV murmur can be heard on thoracic auscultation. The doctor orders radiographs and blood work. The blood work is unremarkable; however, the thoracic radiographs show a slight cardiomegaly. EKG and ECHO are done and PDA is diagnosed. Surgery is performed to tie off the PDA and Bailey has a routine recovery. On the two‐week post op exam, the owner is delighted with Bailey’s recovery. She states that Bailey’s energy has gone up and she’s much friskier at home and at the dog park. Question: Why was Bailey lethargic and resistant to walking around?