CONGESTIVE HEART FAILURE IN DOGS AND CATS

Congestive heart failure (CHF) occurs when the heart cannot pump enough blood to meet the body’s oxygen needs. Blood and fluids accumulate in either the lungs or throughout the body, resulting in difficulty breathing, tiredness and reduced oxygen delivery to muscles.

Unlike being a singular condition, CHF represents the end stage of several types of heart diseases. The majority of cases are identified in association with valvular heart disease or dilated cardiomyopathy in dogs. In cats, hypertrophic cardiomyopathy is the most common association with CHF. Early identification and successful treatment will allow some patients to live a relatively normal quality of life for months to years.

Causes

CHF develops when underlying heart disease gradually weakens the heart’s ability to pump blood effectively.

Degenerative valve disease, which results from chronic damage to the heart valves, causing them to become progressively thicker and leakier, is one of the leading causes of CHF in dogs. Large breed dogs have a high incidence rate of dilated cardiomyopathy, which causes the heart muscle to weaken and enlarge.

Hypertrophic cardiomyopathy, characterized by abnormal thickening of the heart muscle and subsequent impairment of the heart’s filling and pumping capabilities, is the most common cause of CHF in cats.

Additional contributing factors include birth defects of the heart, hypertension, heartworm disease in dogs and systemic illness affecting heart function.

Symptoms

• Persistent coughing (more common in dogs)
• Difficulty breathing or rapid breathing
• Shortness of breath, especially after activity
• Fatigue and reduced exercise tolerance
• Weakness or collapse in severe cases
• Fluid accumulation in the abdomen (swollen belly)
• Bluish gums or tongue due to low oxygen
• Restlessness, especially at night
• Loss of appetite and weight loss
• Open mouth breathing in cats (emergency sign)

Early symptoms in cats may be less apparent than those in dogs. Cats may hide, decrease their level of grooming, or show a marked reduction in physical activity before showing obvious clinical signs.

Risks

Congestive heart failure (CHF) is a progressive and potentially fatal disease. As heart function deteriorates, fluid accumulation in the lungs (pulmonary edema) results in significant respiratory distress.

In the final stages of this condition, the pet develops severe respiratory distress due to a lack of oxygenation of their tissues and prolonged exposure to low oxygen levels will ultimately lead to organ failure and death.

Patients with CHF may have a sudden worsening of their condition due to exertion or stress. Without intervention, CHF can also significantly shorten a pets life expectancy, as well as result in a decline in quality of life.

Complications may include:

• Pulmonary Edema
• Pleural Effusion (Increased pressure around the lungs resulting from fluid accumulation)
• Arrhythmias
• Organ Damage from Poor Perfusion

Diagnosis

Diagnosis is made by performing a thorough examination of the patient along with advanced diagnostic tests.

Abnormal heart sounds such as murmurs and irregular heart rhythms are commonly identified on physical examination. Imaging modalities are then used to confirm the diagnosis as well as assess the degree of severity of CHF.

Common Diagnostic Tools

• Chest X-Ray shows fluid accumulation in the lung or heart enlargement
• Echocardiogram shows the structure and function of the heart
• An electrocardiogram is an evaluation of the heart rhythm
• Blood Tests help in the evaluation of each major organ system
• Blood Pressure provides insight into the possible underlying cause

The results of these tests will establish a diagnosis as well as guide the treatment plan.

Treatment

CHF is managed by improving heart function and reducing excess fluid in the lungs and body. While CHF is not typically curable, in most cases, CHF can be controlled through various treatment options.

Medical Management

Commonly used medications for CHF treatment include:

Diuretics to remove excess fluid from the body

• ACE inhibitors to reduce blood pressure and improve heart efficiency
• Pimobendan to strengthen heart contractions in dogs
• Beta blockers or calcium channel blockers in selected cases
• Oxygen therapy in emergencies

Lifestyle Management

• Reducing physical stress and avoiding overexertion
• Maintaining a low sodium diet to limit fluid retention
• Regular monitoring of breathing rate and body condition
• Frequent veterinary checkups to adjust medications

Severe CHF patients may require hospitalization for stabilization.

Prevention

Some forms of congestive heart failure cannot be prevented, such as those due to inherited heart defects. Still, timely identification of and management of heart diseases may slow their development.

Regular veterinary exams are critical, particularly for aging animals or breeds that have higher rates of developing heart disease. Early medical intervention for heart murmurs, managing blood pressure and preventing heartworm disease in dogs will help reduce the risk of developing CHF.

Maintaining your pet’s ideal body weight and allowing them the right amount of activity will support long term cardiovascular health.