Congestive heart failure (CHF) is a clinical syndrome in dogs caused by severe heart disease that leads to fluid retention in specific parts of the body. The location of fluid retention depends on which side of the heart is affected: the left side causes fluid retention in the lungs or pleural cavity, while the right side causes fluid retention in the abdomen or pleural cavity. CHF occurs when the pressure in veins and capillaries increases due to heart disease, causing fluid to leak into surrounding tissues.
Causes of CHF
CHF is a result of severe heart disease that elevates the resting (diastolic) cardiac pressure. Conditions such as mitral or tricuspid valve disease, dilated cardiomyopathy, hypertrophic cardiomyopathy, congenital cardiac defects, and heartworm disease can lead to CHF. Congenital diseases obstructing outflow from the heart, like pulmonic stenosis or aortic stenosis, do not typically cause CHF.
Clinical Signs of CHF
The clinical signs of CHF depend on which side of the heart is affected. Left-sided CHF causes pulmonary edema and pleural effusion, leading to increased breathing rates and difficulty in breathing. Coughing may or may not be a feature of CHF. Right-sided CHF usually presents as abdominal swelling (ascites), discomfort when lying down, and labored breathing if fluid accumulates in the chest cavity.
Diagnosis of CHF
The diagnosis of CHF involves identifying clinical signs of increased respiratory rate and difficulty in breathing along with severe heart disease. Chest X-rays can reveal an enlarged heart and opacity in the lungs or fluid in the chest cavity. Cardiac ultrasound (echocardiogram) may be recommended for further evaluation, typically performed by veterinary cardiologists or radiologists.
Treatment of CHF
Treatment for CHF involves managing the underlying heart disease and addressing fluid accumulation. Correcting the cause, such as closing a congenital shunt or repairing a leaking mitral valve, can alleviate the problem. Medical treatment often includes diuretics like furosemide or torsemide to reduce blood volume and fluid buildup. Other medications like angiotensin-converting-enzyme inhibitors, pimobendan, thiazide diuretics, and spironolactone may also be used in combination with diuretics.
In right-sided CHF, fluid buildup may require repeated manual removal through large catheters. Medical treatment combined with manual fluid removal can improve the patient's comfort.
Monitoring and Prognosis
Monitoring the respiratory rate is crucial in managing left-sided CHF. Stable respiratory rate during sleep indicates good control of CHF, but an increase in sleeping respiratory rate might require treatment adjustments. Regular bloodwork might be monitored to check for side effects of medications. The prognosis for CHF depends on the underlying disease, but survival is generally less than two years for common diseases like mitral valve disease and hypertrophic cardiomyopathy.
Congestive heart failure in dogs is a clinical syndrome caused by severe heart disease leading to fluid retention in specific parts of the body. Identifying the side of the heart affected is crucial in understanding the clinical signs and initiating appropriate treatment. While CHF has no cure, medical management and monitoring can significantly improve the patient's quality of life and extend survival in many cases. Early detection and proper management are essential for better outcomes.
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