General Information
Dilated cardiomyopathy (DCM) is an adult-onset heart disease seen most often in large to giant breed dogs, particularly in breeds such as the Doberman, but can also be seen in medium size dogs, such as the Cocker Spaniel. DCM is characterized by dilated heart chambers, a thin heart muscle, and decreased contractility (decreased ability of the heart muscle to contract), which results in decreased ability of the heart to pump blood throughout the body. DCM is a progressive disease that can be managed with medication but cannot be cured. Patients with DCM often experience progressive weakness and lethargy, progressive weight loss, and are at risk for congestive heart failure. In addition, they can die suddenly secondary to cardiac rhythm disturbances.
Diagnosis
Dilated cardiomyopathy often causes only subtle, if any, changes to your pet’s physical examination. Heart murmurs are caused by turbulent blood flow as blood leaks backwards across the affected valve, and if present, are often quiet. Other abnormal heart sounds, such as a gallop sound, or an arrhythmia (abnormal heart rhythm) may be identified. Thoracic radiographs often do not show significant enlargement of the heart in the early stages of DCM. The best way to diagnose DCM is by referral to a cardiologist for an echocardiogram (ultrasound of the heart) to evaluate for specific heart chamber enlargement and to evaluate heart function. An electrocardiogram (ECG) and or holter monitor may be recommended to evaluate arrhythmias. Other diagnostics, such as a blood pressure or blood work may be recommended to further evaluate for other concurrent diseases or factors which may complicate management of DCM.
Complications and Sequelae
Signs of heart failure include cough, difficulty breathing, weakness, lethargy, exercise intolerance, and collapse. Less commonly, abdominal distension from fluid build-up in the abdomen may occur. In addition, arrhythmias may develop or worsen, and lead to signs of weakness, lethargy, and collapse. These arrhythmias may also increase the risk of sudden death.
Pulmonary hypertension (PH), or high blood pressure in the lungs, may develop secondary to mitral valve disease. PH is best controlled by managing the underlying valvular disease. Medications can be added in if the PH increases in severity resulting in more pronounced clinical signs including exercise intolerance and collapse.
Treatment
The goal is to keep your pet out of heart failure without harming their kidneys and to help them maintain a good quality of life. Medications used to treat heart failure include diuretics to help remove extra fluid from the body; a medication to help improve function of the heart; and other medications to help prevent fluid retention and fibrosis (scarring) of the heart muscle. Other medications may be used to help control coughing or to control PH.
It is important your pet not be fed a diet or snacks that are very high in salt. This includes things like bacon, pig ears, sausage, etc. It is best to maintain them on a moderately sodium restricted diet. This would include any senior or kidney diet.
It is best to allow your pet to set their own pace. It is not uncommon for dogs with heart disease to be exercise intolerant, particularly in hot summer months.
Prognosis
In general, DCM with heart failure carries a guarded prognosis, with an average life span after diagnosis of heart failure (fluid in the lungs or abdomen), on appropriate treatment, is months to a year. If atrial fibrillation (a frequent arrhythmia) is also present, the prognosis is guarded to poor, with an average survival time of weeks to months. Frequent monitoring is important in maximizing treatment of heart failure, to help your pet feel as good as possible, for as long as possible.
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