Dyspnea (Trouble Breathing) in Dogs

Radiograph of a dog who suffered acute dyspnea for less than 8 hours duration. He has lost some weight over the last month.

What are the historical findings in heart failure?

• Syncope/lethargy - due to reduced cerebral perfusion.
• Weakness/reduced stamina - due to reduced skeletal muscle perfusion.
• Dyspnea/wheeze/cough/orthopnea - Dyspnea is due to pulmonary edema or pleural effusion. Cough may occur due to pulmonary edema or due to mitral valve insufficiency with left atrial enlargement and compression of the left main-stem bronchus; this latter cause may often occur in the absence of congestive heart failure. Many dogs with heart failure may not cough, whereas dyspnea, wheezes and sometimes orthopnea (difficulty breathing when lying down) are common historical findings. Some dogs will cough with relatively mild edema and others only cough with severe pulmonary edema. It appears that the speed with which the pulmonary edema develops may play a role in determining when or if cough is to develop.
• Abdominal distention - due to ascites and/or Hepatomegaly or splenomegaly.

With Content by:
Michael R. O'Grady, DVM, MSc, Diplomate ACVIM (Cardiology)
M. Lynne O'Sullivan, DVM, DVSc, Diplomate ACVIM (Cardiology)
Veterinary Cardiology Online, An educational site for veterinary students and practitioners.