CARDIOMYOPATHY SIGNS & SYMPTOMS
Cardiomyopathy is a complex disease where the physical characteristics of the heart muscle and symptoms vary considerably. Each child may experience symptoms differently, and verifying signs can be complicated by the inability of babies and young children to communicate how they feel. Symptoms can be absent (asymptomatic), mild or severe.
Children may be diagnosed following the detection of a heart murmur during a routine pediatric visit or special screening when another family member is found to have cardiomyopathy. However, a child with cardiomyopathy does not always present with a heart murmur. Murmurs occur in about a third to half of hypertrophic cardiomyopathy patients and are usually due to the obstruction of the ventricle or leaking in one of the heart valves. Because cardiomyopathy is not easily detected in physical examinations, many children are only diagnosed in the later stages of the disease.
A formal diagnosis is made by imaging the heart muscle, most commonly with echocardiography. The echocardiogram helps to determine how well the heart muscle is functioning. In some cases, the contractile force of the heart is diminished and/or the filling of the heart is impaired, leading to signs of heart failure. Each type of cardiomyopathy has slightly different signs and therefore requires varying short and long term medical treatment.
Infants and children with dilated cardiomyopathy most often present with signs of congestive heart failure. This is when the heart cannot pump enough blood to meet the body's needs and there is a buildup of fluid in the body tissues and lungs. The heart also becomes congested with blood. Common symptoms in infants are labored breathing that is faster and deeper than normal (tachypnea) when lying down or with exertion, poor appetite and slow weight gain. Older children may show signs of poor exercise tolerance and gastrointestinal distress. Upon examination, children may show swelling of the lungs, an enlarged liver and heart, and abnormal lung and heart sounds related to a rapid, galloping heartbeat and congestion in the lungs. In more severe cases, patients may experience fainting (syncope), irregular heartbeats (arrhythmias), or sudden cardiac death.
Children with cardiomyopathies of a metabolic nature may have additional symptoms of low blood sugar (hypoglycemia), excessive acidity in the blood (metabolic acidosis) or neurological abnormalities such as decreased muscle tone (hypotonia) and changes in mental status or behavior (encephalogpathy). These symptoms may arise when the body's metabolic demand exceeds supply or when the body cannot break down accumulated toxins.
There is tremendous variation in the presentation and course of hypertrophic cardiomyopathy. In some cases, the observance of a murmur will lead to a diagnosis of hypertrophic cardiomyopathy. In infants, common symptoms are difficulty breathing, excessive sweating (diaphoresis), poor appetite and failure to thrive. Older children with obstructive hypertrophic cardiomyopathy typically show signs of shortness of breath (dyspnea), chest pain or pressure (angina), dizziness (presyncope) and/or fainting (syncope) upon exertion, and reduced activity tolerance. Infants and children with non-obstructive hypertrophic cardiomyopathy may have milder symptoms.
Rapid, forceful or irregular heartbeats (palpitations and arrhythmias) are common complications associated with hypertrophic cardiomyopathy. In the later stages of the disease, symptoms similar to dilated cardiomyopathy may present such as coughing, abdominal pain, weakness, breathing difficulties and fluid accumulation in the lungs and body.
Symptoms are often subtle in patients with restrictive cardiomyopathy. However, small children may show poor appetite, growth failure and fatigue easily. Older children may experience rapid breathing while resting or shortness of breath on exertion (dyspnea), fainting (syncope), chest pain (angina), an upset stomach and a dry cough. Although swelling of the lungs is uncommon initially, over time venous congestion and hypertension may cause an enlarged liver and excess fluid in the abdomen and lower leg. Common complications of restrictive cardiomyopathy are arrhythmias, heart block, blood clots and sudden death. Similar to the other forms of cardiomyopathy, the disease can progress to congestive heart failure.
Arrhythmogenic Right Ventricular Cardiomyopathy
This is extremely rare in children and there are usually no signs or symptoms until later in life. Common symptoms include shortness of breath, palpitations, fainting, swollen neck veins, abdominal discomfort and irregular heart rhythms. In the later stages of congestive heart failure, there may also be kidney and liver malfunction, hypertrophy or enlargement of the heart, congestion in the lungs, and swelling in the liver, gastrointestinal tract and legs.
Left Ventricular Non-Compaction Cardiomyopathy
Patients with left ventricular non-compaction cardiomyopathy (LVNC) may have symptoms of heart failure, shortness of breath (dyspea), poor growth, fatigue or irregular heartbeats (arrhythmias) that may increase the risk of sudden cardiac death. In older individuals, blood clots can form in the recesses of the heart muscle and travel to other parts of the body and block blood flow to the brain (stroke) or to other organs (thromboembolism).
Properly diagnosing LVNC is difficult because of its obscure visual characteristics. Defining LVNC on echocardiography has not been standardized, although criteria have been proposed. These include: (1) appearance of at least 4 trabeculations and deep trabecular recesses, (2) blood flow from the ventricular cavity into the recesses, and (3) an appearance of a two layered structure in the muscle wall of the ventricle with a end-systolic ratio of trabeculated muscle to compacted muscle of greater than 2:1.