Shock Due to Heart Failure in Cats

In some cases, heart disease may already be diagnosed and some factor has exacerbated the condition causing heart failure and shock. Because symptoms of shock in cats are more subtle than in other animals, it can rapidly progress to a critical stage. Shock due to heart failure has a guarded to poor prognosis and requires immediate attention by a veterinarian. 

Shock due to heart failure in cats is a life-threatening condition that occurs when the heart is unable to provide adequate circulation to provide oxygenated blood to organs and tissues. 

When heart function is impaired, proper oxygenation of blood through normal cardiac/pulmonary processes and circulation of the oxygenated blood to tissues and organs becomes impaired, resulting in shock. The symptoms of shock due to heart failure and the symptoms of the heart failure itself overlap, to a large degree. When heart failure occurs, lack of oxygenated blood causes the body to react with compensatory measures to divert blood to vital organs by dilating blood vessels, which lowers blood pressure, further decreasing oxygenated blood supply to other tissues. This causes an already damaged or malfunctioning heart to be required to pump more blood, weakening the heart and creating further heart failure, less oxygenated blood circulating, and further symptoms of shock. As vital organs are deprived of oxygenated blood, organ failure, respiratory distress, buildup of fluid in tissues, weakness, and collapse occur. If left untreated, irreversible organ failure and death will result. 

Symptoms of shock due to heart failure may be less obvious than in dogs or other animals. Many symptoms overlap with symptoms of the heart failure itself. Both are life threatening conditions. Symptoms to be aware of are:

• Low blood pressure
• Decreased oxygen to tissues (pale mucous membranes)
• Lethargy/weakness
• Disorientation
• Collapse
• Weak pulse
• Cold extremities
• Low body temperature
• Lactic acid buildup in blood due to poor oxygenization contributes to organ malfunction from acidic blood.
• Decreased urinary output/kidney failure
• Increased or decreased heart rate
• Abnormal cardiac rhythms
• Cough
• Hemorrhagic disorders/capillary bleeds
• Respiratory distress

As shock progresses, congestive heart failure leads to pulmonary function impairment and fluid buildup in lungs and tissues.

• Pulmonary edema is associated with left-sided cardiac failure
• Pleural effusion is associated right sided cardiac failure

Heart failure may be due to congenital defects or acquired as a result of disease. Heart failure leads to impaired oxygenation of blood, resulting in shock.

Cause of Heart disease

• Arrhythmia
• Blood clot of heart
• Obstruction
• Dilated heart muscle
• Pericardial constriction
• Abnormalities in the heart wall
• Heart valve defects
• Fluid in heart sac

Causes of Secondary Heart Disease

• Anemia
• Blood poisoning (sepsis)
• Pulmonary blood clot
• Heartworm
• Hyperthyroidism

Your veterinarian will perform a complete physical exam including measuring blood pressure

and taking a medical history of your cat. Your veterinarian may immediately provide supportive care for your pet prior to a diagnosis of shock, due to the urgency of the condition.

Diagnosis of shock due to cardiac failure will depend on identifying heart failure. A medical history, including any information regarding symptoms of heart conditions or disease in your cat, will be critical in identifying the cause of shock as cardiac. 

Your veterinarian will also need to rule out other conditions causing shock or contributing factors such as viral infection, parasitic infection, or bacterial infection. Blood and urine tests to look for signs of heart failure and other underlying conditions will be performed. Electrocardiography, x-rays and echocardiography may be performed to identify heart malfunction and abnormalities. 

Treatment of shock due to heart failure is urgent, as this is a life-threatening condition. Hospitalization and aggressive care will be required.

Supportive therapy for treatment of shock will begin immediately. Intravenous therapy will be administered to increase blood pressure and medication to ensure adequate blood flow to vital organs will be administered. Vasopressor drugs to constrict dilated blood vessels and improve blood pressure may be administered. Oxygen will also be administered to your cat to increase oxygenation of blood supply to tissues and organs. Blood transfusion may also be required. Additional supportive care such as heat support and painkillers may be administered. 

If fluid buildup has occurred, drainage of the pericardium may also be performed by your veterinarian. Heart functioning will be closely monitored and appropriate treatment for heart failure administered. Prognosis of shock due to heart failure is guarded, in spite of treatment, fatality is possible.

Recovery from heart failure and shock due to heart failure will require close monitoring by your veterinarian. Follow-up treatment in the form of cardiac therapy and supportive care including continued intravenous therapy to restore appropriate blood chemistry, blood pressure, and oxygenation may be required As a pet owner, you will be required to provide close monitoring of your pet and administer any treatments required to restore cardiac functioning such as medication and diet.

Rest in a stress-free environment for several weeks including any therapy recommended by your veterinarian will be required.