Progression of Congestive Heart Failure in Dogs

Congestive heart failure occurs when a dog's heart weakens and can no longer effectively circulate blood throughout the body. The underlying cause of congestive heart failure is often unknown, though various conditions can result in heart failure. Some of these conditions, such as dilated cardiomyopathy, are thought to have a genetic component in some breeds.

  1. Early Stages

    • Often the early stages of congestive heart failure will not lead to any outward signs of a problem. A dog's body will compensate for decreased heart function by retaining sodium, increasing the heart rate and constricting the blood vessels.

    First Signs

    • Typically the first signs an owner will notice in a dog with congestive heart failure are exercise intolerance, lethargy and coughing, especially at night. As the condition progresses, more obvious signs may appear such as rapid breathing, decreased appetite with noticeable weight loss or swelling of the abdomen.

    Fluid Retention

    • If the heart failure is on the left side, fluid will accumulate in the lungs, leading to pulmonary edema. The dog may cough up a bloody fluid. With right-side heart failure, fluid builds up in the abdomen and chest cavity, and the legs may also swell.

    Late Stage

    • In the late stages of congestive heart failure, the dog will be obviously uncomfortable and will sit with his head extended and elbows spread. A rapid, thin and irregular pulse is common, and the dog may experience fainting spells (syncope). His tongue and gums will be a pale, bluish-gray color and he will have difficulty breathing normally.

    Prognosis

    • Medication can relieve or minimize the symptoms of congestive heart failure, especially in the middle stages, but the condition is not reversible. Cardiac drugs are given to lower the blood pressure, thereby decreasing the heart's workload, and to improve the heart's strength and contractility. Diuretics remove excess fluids from the body. With medication and proper veterinary care, many dogs can live for extended periods after diagnosis with congestive heart failure.