Veterinary Clinical Medicine-I (General and Systemic)

Congestive heart failure - Basics

CONGESTIVE HEART FAILURE

• The failure of the heart to adequately pump blood is the simplest definition of cardiac failure.
• Congestive heart failure is the clinical syndrome initiated by myocardial dysfunction or failure and is characterized by pulmonary or systemic venous congestion or both and low cardiac output.
• The Congestive aspects of heart failure results from the body’s attempts to compensate for a low cardiac output principally by sympathetic reflexes and by the renal retention of fluid.
• Indeed, these compensatory mechanisms frequently determine whether cardiac disease is clinically detectable or not, and they form the basis for many diagnostic and therapeutic considerations.
• Fluid retention - a low cardiac output can cause anuria, and the urinary output is generally less when the cardiac output is below normal. Similarly, the relationship between cardiac disease and the accumulation of edema and accites has long been recognized, as has the causal relationship between increased salt intake and the progressive accumulation of fluid in congestive heart failure.

Clinical Manifestations of CHF

Clinical signs of Left Heart Failure

• Mainly pulmonary components, which on exertion causes
• Cough
• Orthopnea
• Paroxysmal dyspnea or cardiac asthma
• Cyanosis
• Hemoptysis
• Varying degrees of pulmonary edema
• Animal with left ventricular failure are frequently reported to develop respiratory distress while lying down resting. This is due to the escape of fluid into the tissues as a result of daily activity which is reabsorbed while resting, thus expanding, the blood volume and creating respiratory distress. The term Orthopnea applies for this occurrence, such patients present with a history of not resting well during, the night.

Clinical Signs of Right Side Heart Failure

• Generalized systemic venous congestion
• Distension of the jugular veins and other superficial veins
• Hepatic & splenic enlargement
• Effusion of fluid in serous cavities
• Subcutaneous edema
• Other features of congestive heart failure when there is generalized distention of the superficial veins.
• Due to the increase in the central venous press with right heart failure. The jugular veins remain distended even when the head is elevated.

Hepatomegaly and Splenomegaly

• Hepatomegaly and Splenomegaly are consequences of chronically elevated systemic venous pressure. Hepatic function test are usually moderately elevated (SGPT) which is central lobular necrosis. Also noted are mild to moderate elevation in the SGOT test, alkaline phosphatase and urobilinogen levels.

Ascites

• Ascites in the dog, is a very common occurrence and tends to develop long before subcutaneous edema becomes apparent. The ascites fluid that in right heart failure is initially a transudate with a specific gravity below l.018. With chronic ascites the fluid frequently becomes blood tinged and the specific gravity may rise above l.018.