**4. Dilated cardiomyopathy**

*3.3.2. Metabolic disorders*

296 Cardiomyopathies

unable to use the body's fuel correctly.

*3.3.3. Malformation syndromes associated with cardiomyopathy*

stature, webbed neck, wide set eyes, low set ears and extra skin folds.

symptoms of heart failure.

**3.4. Forms of cardiomyopathy**

Inborn errors of metabolism consist of numerous infiltrative storage diseases, abnormal energy production, biochemical deficiencies and disorders related to toxic substances accumulating in the heart. This category also includes mitochondrial abnormalities (i.e. MELAS, MERRF, respiratory chain diseases, mitochondrial myopathies), fatty acid oxidation defects (carnitine deficiency, VCHAD, LCHAD, LCAD, MCAD), Pompe disease and Barth syndrome. When the demand for energy exceeds what the body can supply (i.e. during illness, physical stress or decreased oral intake), patients with impaired energy metabolism are unable to maintain their body's biochemical stability. This may lead to low blood sugar, excessive acidity in the blood and/or high ammonia levels that put additional strain on the heart.Metabolic disorders are inherited by autosomal recessive transmission (each parent contributes a defective gene) or Xlinked transmission (mother contributes defective gene). Usually patients appear to be physically normal in early childhood but as the body's energy production continues to be impaired, toxic substances may accumulate throughout the body leading to multiple organ failure. Common symptoms include muscle weakness, decreased muscle tone, growth retardation, developmental delays, failure to thrive, constant vomiting and lethargy. In critical states, the child may exhibit stroke like symptoms, seizures, have low blood sugar, and be

In contrast, patients with storage diseases such as Pompe, Cori, and Andersen disease cannot break down glycogen, the storage form of sugar. These syndromes are characterized by problems with growth, brain dysfunction, decreased muscle tone, muscle weakness, and

Malformation syndromes are characterized by minor and major physical abnormalities with distinctive facial features. It is caused by genetic mutations through autosomal dominant, autosomal recessive, or X-linked recessive inheritance. It can also be cause by a chromosomal defect where a specific chromosome is deleted or duplicated. Noonan syndrome is the most common form associated with pediatric cardiomyopathy. Common symptoms include short

There are four main types of nonischemic cardiomyopathy that are recognized by the World Health Organization: dilated (DCM), hypertrophic (HCM), restrictive (RCM) and arrhythmo‐ genic right ventricular (ARVC). Each form is determined by the nature of muscle damage. With some patients, cardiomyopathy may be classified as more than one type or may change from one type to another over time. According to the pediatric cardiomyopathy survey, dilated cardiomyopathy is the most common (58%), followed by hypertrophic cardiomyopathy (30%) and a few cases of restrictive cardiomyopathy (5%) and arrhythmogenic right ventricular cardiomyopathy (5%). Although not formally categorized by the World Health Organization, left ventricular non-compaction cardiomyopathy (LVNC) is increasingly being recognized. Dilated or congestive cardiomyopathy (DCM) is diagnosed when the heart is enlarged (dilated) and the pumping chambers contract poorly (usually left side worse than right). A diagram and echocardiogram comparing a normal heart and a heart with DCM (fig. 15)

**Figure 15.** A normal heart is shown on the left compared to a heart with dilated cardiomyopathy on the right.

This condition is the most common form of cardiomyopathy and accounts for approximately 55–60% of all childhood cardiomyopathies. It can have both genetic and infectious/environ‐ mental causes.It is more commonly diagnosed in younger children with the average age at diagnosis being 2 years. Dilated cardiomyopathy can be familial (genetic), and it is estimated that 20–30% of children with DCM have a relative with the disease, although they may not have been diagnosed or have symptoms.

#### **4.1. Signs and symptoms of DCM**

Dilated cardiomyopathy can appear along a spectrum of no symptoms, subtle symptoms or, in the more severe cases, congestive heart failure (CHF), which occurs when the heart is unable to pump blood well enough to meet the body tissue needs for oxygen and nutrients.When only subtle symptoms exist, infants and young children are sometimes diagnosed with a viral upper respiratory tract infection or recurrent "pneumonia" without realizing that a heart problem is the basis for these symptoms. Older children and adolescents are less likely to be diagnosed with viral syndromes and more likely to present with decreased exercise capacity or easy fatigability. With CHF, babies and young children will usually have more noticeable clinical changes such as irritability, failure to thrive (poor gain weight), increased sweating especially with activities, pale color, faster breathing and/or wheezing. In older children, congestive heart failure can manifest as difficulty breathing and/or coughing, pale color, decreased urine output and swelling, excessive sweating, and fatigue with minimal activities. Until the diagnosis is made in many children, chronic coughing and wheezing, particularly during activities, can be misinterpreted as asthma.Some patients with DCM caused by viral myocarditis (weakened, enlarged heart muscle usually due to a viral infection) can have a rapid increase in the number and severity of CHF symptoms such that within 24–48 hours the child can become very ill requiring emergency hospitalization, and occasionally, advanced life support.Symptoms due to heart rhythm problems (or arrhythmias, which means irregular, fast or slow heart rates) can also be either the first symptom or a symptom that appears after other symptoms have led to a diagnosis of DCM. Symptoms of rhythm problems include palpitations (feeling of funny or fast heart beats), syncope (fainting), seizures (convulsions), or even sudden cardiac arrest (heart stops beating effectively requiring resuscitation). These symptoms can occur at any age and with any stage of cardiomyopathy, even if other more severe symptoms of congestive heart failure have not yet appeared.

into the heart (while watching its course on a TV monitor) so that pressures within the heart chambers can be measured. A cardiac biopsy, which involves removing tiny pieces of heart muscle for inspection under the microscope, may be performed to help distinguish between

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Currently, there are no therapies that can "cure" DCM; however, many treatments are available that can improve symptoms and decrease risk in children with DCM. The choice of a specific therapy depends on the clinical condition of the child, the risk of dangerous events and the ability of the child to tolerate the therapy. In the following sections, current medical

The majority of children with DCM have signs and symptoms of heart failure. The most common types of medications used to treat heart failure include diuretics, inotropic agents,

**Diuretics,** sometimes called "water pills," reduce excess fluid in the lungs or other organs by increasing urine production. The loss of excess fluid reduces the workload of the heart, reduces swelling and helps children breathe more easily. Diuretics can be given either orally or intravenously. Common diuretics include furosemide, spironolactone, bumetanide and metolazone. Common side effects of diuretics include dehydration and abnormalities in the

**Inotropic Agents** are used to help the heart contract more effectively. Inotropic medications and are most commonly used intravenously to support children who have severe heart failure and are not stable enough to be home. Common types of inotropic medications include:

**•** Digoxin (taken by mouth): improves the contraction of the heart. Side effects include low

**•** Dobutamine, dopamine, epinephrine, norepinephrine (intravenous medications given in the hospital): medications that increase blood pressure and the strength of heart contrac‐ tions. Side effects include increased heart rate, arrhythmias and for some, constriction of the

**•** Vasopressin (intravenous medication): increases blood pressure and improves blood flow to the kidneys. Side effects include excessive constriction of the arteries and low sodium.

**•** Milrinone (intravenous medication): improves heart contraction and decreases the work of the heart by relaxing the arteries. Side effects include low blood pressure, arrhythmias and

**Afterload Reducing Agents** reduce the work of the heart by relaxing the arteries and allowing the blood to flow more easily to the body. Common afterload reducing medications include:

heart rate, and, with high blood levels, vomiting and abnormal heart rhythm.

infectious and genetic causes.

and non-medical therapies for DCM are summarized.

afterload reducing agents and beta-blockers.

blood chemistries (particularly potassium loss).

**4.3. Current treatment**

**4.4. Medical therapy**

arteries.

headaches.

#### **4.2. Diagnosis of DCM**

Once there is clinical suspicion based on the patient history and physical exam, the diagnosis of DCM is primarily based on echocardiography. With this test, will be using ultrasound beams to evaluate the heart looking for dilated chambers and decreased pump function. Along with the echocardiogram, there are other tests that will likely be done to confirm the diagnosis or provide clues as to the cause.A chest X-ray will show the heart size and can be used as a reference to follow increases in heart size that may occur over time. An electrocardiogram, or EKG, records the electrical conduction through the heart and is used to look for evidence of thickened or enlarged chambers as well as abnormal heart beats that can occur in children with this diagnosis. To more completely evaluate for the presence or absence of these abnormal heart rhythms, which may effect treatment, your doctor may also order a Holter monitor which records heart beats over a 24–48 hour period. A treadmill test can also be useful in some children (beyond age 5–7 years) who can cooperate with this study. This exercise test is used to assess the energy reserve child's heart and, in cases when children do not respond ade‐ quately to medicines, this test may also help predict the need for heart transplantation.De‐ pending on child's age, a battery of blood tests may be done in order to identify treatable causes for the cardiomyopathy. This may include testing for certain viral infections such as adenovirus and the Coxsackie viruses as they have been associated with DCM especially in younger children. In many cases, no cause is discovered, and the cardiomyopathy may be referred to as "idiopathic" (cause unknown). Many heart failure specialists believe this "idiopathic" form of the cardiomyopathy is genetic. While genetic screening has not yet become a standard procedure, some physicians may send blood to molecular testing labs located in a few centers around the country so that limited genetic testing can be performed looking for possible mutations currently known to cause dilated cardiomyopathy. evaluation, usually with echo, of other family members is recommended to rule out presence of this disease in other close relatives (parents, siblings).

Finally, in more advanced cases of DCM, cardiac catheterization may be performed. During this procedure, a catheter (thin plastic tube) will be slowly advanced through an artery or vein into the heart (while watching its course on a TV monitor) so that pressures within the heart chambers can be measured. A cardiac biopsy, which involves removing tiny pieces of heart muscle for inspection under the microscope, may be performed to help distinguish between infectious and genetic causes.

#### **4.3. Current treatment**

and swelling, excessive sweating, and fatigue with minimal activities. Until the diagnosis is made in many children, chronic coughing and wheezing, particularly during activities, can be misinterpreted as asthma.Some patients with DCM caused by viral myocarditis (weakened, enlarged heart muscle usually due to a viral infection) can have a rapid increase in the number and severity of CHF symptoms such that within 24–48 hours the child can become very ill requiring emergency hospitalization, and occasionally, advanced life support.Symptoms due to heart rhythm problems (or arrhythmias, which means irregular, fast or slow heart rates) can also be either the first symptom or a symptom that appears after other symptoms have led to a diagnosis of DCM. Symptoms of rhythm problems include palpitations (feeling of funny or fast heart beats), syncope (fainting), seizures (convulsions), or even sudden cardiac arrest (heart stops beating effectively requiring resuscitation). These symptoms can occur at any age and with any stage of cardiomyopathy, even if other more severe symptoms of congestive

Once there is clinical suspicion based on the patient history and physical exam, the diagnosis of DCM is primarily based on echocardiography. With this test, will be using ultrasound beams to evaluate the heart looking for dilated chambers and decreased pump function. Along with the echocardiogram, there are other tests that will likely be done to confirm the diagnosis or provide clues as to the cause.A chest X-ray will show the heart size and can be used as a reference to follow increases in heart size that may occur over time. An electrocardiogram, or EKG, records the electrical conduction through the heart and is used to look for evidence of thickened or enlarged chambers as well as abnormal heart beats that can occur in children with this diagnosis. To more completely evaluate for the presence or absence of these abnormal heart rhythms, which may effect treatment, your doctor may also order a Holter monitor which records heart beats over a 24–48 hour period. A treadmill test can also be useful in some children (beyond age 5–7 years) who can cooperate with this study. This exercise test is used to assess the energy reserve child's heart and, in cases when children do not respond ade‐ quately to medicines, this test may also help predict the need for heart transplantation.De‐ pending on child's age, a battery of blood tests may be done in order to identify treatable causes for the cardiomyopathy. This may include testing for certain viral infections such as adenovirus and the Coxsackie viruses as they have been associated with DCM especially in younger children. In many cases, no cause is discovered, and the cardiomyopathy may be referred to as "idiopathic" (cause unknown). Many heart failure specialists believe this "idiopathic" form of the cardiomyopathy is genetic. While genetic screening has not yet become a standard procedure, some physicians may send blood to molecular testing labs located in a few centers around the country so that limited genetic testing can be performed looking for possible mutations currently known to cause dilated cardiomyopathy. evaluation, usually with echo, of other family members is recommended to rule out presence of this disease in other close

Finally, in more advanced cases of DCM, cardiac catheterization may be performed. During this procedure, a catheter (thin plastic tube) will be slowly advanced through an artery or vein

heart failure have not yet appeared.

**4.2. Diagnosis of DCM**

298 Cardiomyopathies

relatives (parents, siblings).

Currently, there are no therapies that can "cure" DCM; however, many treatments are available that can improve symptoms and decrease risk in children with DCM. The choice of a specific therapy depends on the clinical condition of the child, the risk of dangerous events and the ability of the child to tolerate the therapy. In the following sections, current medical and non-medical therapies for DCM are summarized.

#### **4.4. Medical therapy**

The majority of children with DCM have signs and symptoms of heart failure. The most common types of medications used to treat heart failure include diuretics, inotropic agents, afterload reducing agents and beta-blockers.

**Diuretics,** sometimes called "water pills," reduce excess fluid in the lungs or other organs by increasing urine production. The loss of excess fluid reduces the workload of the heart, reduces swelling and helps children breathe more easily. Diuretics can be given either orally or intravenously. Common diuretics include furosemide, spironolactone, bumetanide and metolazone. Common side effects of diuretics include dehydration and abnormalities in the blood chemistries (particularly potassium loss).

**Inotropic Agents** are used to help the heart contract more effectively. Inotropic medications and are most commonly used intravenously to support children who have severe heart failure and are not stable enough to be home. Common types of inotropic medications include:


**Afterload Reducing Agents** reduce the work of the heart by relaxing the arteries and allowing the blood to flow more easily to the body. Common afterload reducing medications include:

**•** Angiotensin converting enzyme inhibitors (ACE inhibitors): captopril, enalapril, lisinopril, monopril (taken by mouth). Side effects include low blood pressure, low white blood cell count, high potassium levels and kidney or liver abnormalities.

**4.7. Pacing therapies for DCM**

*4.7.2. Implantable Cardioverter Defibrillator (ICD)*

pacing or the best way to implant the system

**4.8. Surgical options for DCM**

ventricular arrhythmias.

*4.7.3. Biventricular pacemaker*

Pacemakers are small, battery-operated devices that are placed under the skin of the chest or abdomen and attached to electrical wires (leads) which are threaded to the heart. Depending on which type of pacemaker is used, these leads are attached to muscle tissue either on the inside or outside of the heart. The devices monitor the heartbeat and help maintain a regular rhythm in children who are prone to have abnormal heartbeats.In some patients with DCM, the heart rate can become too slow either due to abnormally slow conduction of impulses through the heart or as a side effect of medications. In those instances, a "back-up" pacemaker can be implanted to help maintain an appropriate heart rate.Conversely, as mentioned above, patients with DCM can develop abnormally fast, life-threatening arrhythmias (ventricular tachycardia and/or fibrillation). Implantable cardioverter defibrillators (ICDs) can be used in those children to convert these arrhythmias to a normal rhythm.Finally, a bi-ventricular pacing system has recently become part of the standard therapy in adults with end-stage heart failure associated with DCM, and this treatment modality is currently being evaluated in children.

Pediatric Cardiomyopathies http://dx.doi.org/10.5772/55820 301

ICDs are designed to prevent sudden death from a serious arrhythmia known as ventricular tachycardia or fibrillation. An ICD constantly monitors heart rate, and when ventricular tachycardia or fibrillation is detected, the ICD delivers a shock to the heart that restores normal rhythm. ICDs are used in patients with hypertrophic cardiomyopathy who are felt to be at high risk for a sudden death and in children with dilated cardiomyopathy who have serious

In recent promising studies in adult patients with dilated cardiomyopathy, a special pace‐ maker that can pace both the right and left ventricles has been designed. This system, which has to be specially timed, allows the two ventricles to contract together and improves the synchrony of contraction between the walls of the left ventricle. Study results have shown that, when added to other medical treatments, this mode of pacing has helped some patients live longer with fewer hospitalizations and, in some cases, has decreased the need for transplan‐ tation. At the time of this publication, use of bi-ventricular pacing in children is in the early stages of development. It is not yet known which children may benefit most from this form of

No surgery has been effective in improving the heart function in dilated cardiomyopathy. In a few patients with a severely dilated left ventricle and a very leaky (regurgitant) mitral valve, surgery to repair or replace the mitral valve may help the heart function improve temporarily.

*4.7.1. Pacemakers*


**Beta-blockers** slow the heartbeat and reduce the work needed for contraction of the heart muscle. Slowing down the heart rate can help to keep a weakened heart from overworking. In some cases, beta-blockers allow an enlarged heart to become more normal in size. Common beta-blockers (taken by mouth) include carvedilol, metoprolol, propanolol and atenolol. Side effects include dizziness, low heart rate, low blood pressure, and, in some cases, fluid retention, fatigue, impaired school performance and depression.In addition to improving the symptoms of heart failure, ACE inhibitors and beta-blockers have been shown to return the heart size toward normal and lessen the number of deaths and hospitalizations in adult patients with dilated cardiomyopathy without symptoms. An ACE inhibitor is recommended in children with dilated cardiomy‐ opathy even in the absence of symptoms. Currently, no firm recommendations are available for beta-blockers in children.

#### **4.5. Anticoagulation medications**

In children with a heart that does not contract well, there is a risk of blood clots forming inside the heart possibly leading to a stroke. Anticoagulation medications, also known as blood thinners are often used in these situations. The choice of anticoagulation drug depends on how likely it is that a blood clot will form. Less strong anticoagulation medications include aspirin and dipyridamole. Stronger anticoagulation drugs are warfarin, heparin, and enoxaparin; these drugs require careful monitoring with regular blood testing. While variable, common side effects of anti-coagulants include excessive bruising or bleeding from otherwise minor skin injuries, interaction with other medications and, for warfarin, fluctuations in anticoagu‐ lation blood levels caused by changes in daily dietary intake.

#### **4.6. Anti-arrhythmia medications**

In some DCM patients, especially those with very dilated and poorly contractile ventri‐ cles, there may be a higher risk of an abnormal, life-threatening heart rhythm (ventricu‐ lar tachycardia), and medications are used to prevent or control this abnormal rhythm which then keeps the heart beating in a regular pattern. Common anti-arrhythmia medications include: amiodarone, procainamide and lidocaine. General side effects may include slower heart rate, lower blood pressure, GI upset (nausea/constipation), head‐ ache, depressed mood, difficulties concentrating, dizziness, and skin rash among others. Consult your cardiologist for drug-specific side effects once a particular anti-arrhythmic medicine has been prescribed.

### **4.7. Pacing therapies for DCM**

#### *4.7.1. Pacemakers*

**•** Angiotensin converting enzyme inhibitors (ACE inhibitors): captopril, enalapril, lisinopril, monopril (taken by mouth). Side effects include low blood pressure, low white blood cell

**•** Angiotensin I Blocker: Losartan (taken by mouth). Side effects include diarrhea, muscle

**Beta-blockers** slow the heartbeat and reduce the work needed for contraction of the heart muscle. Slowing down the heart rate can help to keep a weakened heart from overworking. In some cases, beta-blockers allow an enlarged heart to become more normal in size. Common beta-blockers (taken by mouth) include carvedilol, metoprolol, propanolol and atenolol. Side effects include dizziness, low heart rate, low blood pressure, and, in some cases, fluid retention, fatigue, impaired school performance and depression.In addition to improving the symptoms of heart failure, ACE inhibitors and beta-blockers have been shown to return the heart size toward normal and lessen the number of deaths and hospitalizations in adult patients with dilated cardiomyopathy without symptoms. An ACE inhibitor is recommended in children with dilated cardiomy‐ opathy even in the absence of symptoms. Currently, no firm recommendations are

In children with a heart that does not contract well, there is a risk of blood clots forming inside the heart possibly leading to a stroke. Anticoagulation medications, also known as blood thinners are often used in these situations. The choice of anticoagulation drug depends on how likely it is that a blood clot will form. Less strong anticoagulation medications include aspirin and dipyridamole. Stronger anticoagulation drugs are warfarin, heparin, and enoxaparin; these drugs require careful monitoring with regular blood testing. While variable, common side effects of anti-coagulants include excessive bruising or bleeding from otherwise minor skin injuries, interaction with other medications and, for warfarin, fluctuations in anticoagu‐

In some DCM patients, especially those with very dilated and poorly contractile ventri‐ cles, there may be a higher risk of an abnormal, life-threatening heart rhythm (ventricu‐ lar tachycardia), and medications are used to prevent or control this abnormal rhythm which then keeps the heart beating in a regular pattern. Common anti-arrhythmia medications include: amiodarone, procainamide and lidocaine. General side effects may include slower heart rate, lower blood pressure, GI upset (nausea/constipation), head‐ ache, depressed mood, difficulties concentrating, dizziness, and skin rash among others. Consult your cardiologist for drug-specific side effects once a particular anti-arrhythmic

count, high potassium levels and kidney or liver abnormalities.

**•** Milrinone is an inotropic agent (see above) that also relaxes the arteries.

cramps and dizziness.

300 Cardiomyopathies

available for beta-blockers in children.

lation blood levels caused by changes in daily dietary intake.

**4.5. Anticoagulation medications**

**4.6. Anti-arrhythmia medications**

medicine has been prescribed.

Pacemakers are small, battery-operated devices that are placed under the skin of the chest or abdomen and attached to electrical wires (leads) which are threaded to the heart. Depending on which type of pacemaker is used, these leads are attached to muscle tissue either on the inside or outside of the heart. The devices monitor the heartbeat and help maintain a regular rhythm in children who are prone to have abnormal heartbeats.In some patients with DCM, the heart rate can become too slow either due to abnormally slow conduction of impulses through the heart or as a side effect of medications. In those instances, a "back-up" pacemaker can be implanted to help maintain an appropriate heart rate.Conversely, as mentioned above, patients with DCM can develop abnormally fast, life-threatening arrhythmias (ventricular tachycardia and/or fibrillation). Implantable cardioverter defibrillators (ICDs) can be used in those children to convert these arrhythmias to a normal rhythm.Finally, a bi-ventricular pacing system has recently become part of the standard therapy in adults with end-stage heart failure associated with DCM, and this treatment modality is currently being evaluated in children.

#### *4.7.2. Implantable Cardioverter Defibrillator (ICD)*

ICDs are designed to prevent sudden death from a serious arrhythmia known as ventricular tachycardia or fibrillation. An ICD constantly monitors heart rate, and when ventricular tachycardia or fibrillation is detected, the ICD delivers a shock to the heart that restores normal rhythm. ICDs are used in patients with hypertrophic cardiomyopathy who are felt to be at high risk for a sudden death and in children with dilated cardiomyopathy who have serious ventricular arrhythmias.

#### *4.7.3. Biventricular pacemaker*

In recent promising studies in adult patients with dilated cardiomyopathy, a special pace‐ maker that can pace both the right and left ventricles has been designed. This system, which has to be specially timed, allows the two ventricles to contract together and improves the synchrony of contraction between the walls of the left ventricle. Study results have shown that, when added to other medical treatments, this mode of pacing has helped some patients live longer with fewer hospitalizations and, in some cases, has decreased the need for transplan‐ tation. At the time of this publication, use of bi-ventricular pacing in children is in the early stages of development. It is not yet known which children may benefit most from this form of pacing or the best way to implant the system

#### **4.8. Surgical options for DCM**

No surgery has been effective in improving the heart function in dilated cardiomyopathy. In a few patients with a severely dilated left ventricle and a very leaky (regurgitant) mitral valve, surgery to repair or replace the mitral valve may help the heart function improve temporarily. Heart transplantation is the only effective surgery offered for patients with DCM who have severe heart failure that does not respond to medications or other treatments.

#### **4.9. Cardiac assist devices (Mechanical hearts)**

Cardiac assist devices are machines that do the work of the heart using a mechanical pump to deliver blood to the body. Cardiac assist devices are implanted when all other therapies have failed and the heart failure is severe. They improve blood flow to the body and allow other organs to recover from the stress of heart failure. These devices are typically used as bridges to transplantation. That is, they are used to support a child either until the heart function has recovered enough to effectively circulate blood through the body or until a suitable donor organ can be found. In pediatric patients, they are designed as a temporary means of support and cannot be used as a permanent alternative to the child's own heart or a transplanted heart. Potential complications of cardiac assist devices include infection, blood clots, stroke and mechanical problems with the devices themselves. There are a variety of cardiac assist devices available. The type of cardiac assist device that is used for an individual child depends on body size and also the type of assist support needed.

#### **4.10. Heart transplantation**

Dilated cardiomyopathy is one of the leading reasons for heart transplantation in children. Heart transplant is only considered in children who have such serious heart disease that there are no other medications or support devices available to sustain the child. A heart transplant offers the child with DCM the chance to return to a normal lifestyle.

While a donor heart can cure the symptoms of heart failure and greatly improve survival, it is a major operation with considerable risks and long-term complications. Once a transplant is done, other concerns arise, such as infection, organ rejection, coronary artery disease, and the side effects of medications.

the heart. Often, leakage of the mitral valve causes the blood in the lower chamber (left ventricle) to leak back into the upper chamber (left atrium). In less than 10% of patients, the disease may progress to a point where the heart muscle thins and the left ventricle dilates resulting in reduced heart function similar to that seen in DCM.HCM is most often diagnosed during infancy or adolescence. Gene defects can be familial, and it is estimated that 50–60% of children with HCM have a relative with the disease, although they may not have been

**Figure 16.** A normal heart is shown on the left compared to a heart with a hypertrophic cardiomyopathy on the right.

Pediatric Cardiomyopathies http://dx.doi.org/10.5772/55820 303

There is tremendous variation in how HCM presents and progresses. While some children have no or mild symptoms, others may have more severe symptoms including heart failure. Some patients develop abnormal heart rhythms (arrhythmias) that may put them at increased risk for sudden cardiac death. Children under 1 year of age often have symptoms of congestive heart failure whereas older children may be symptom free and, therefore, may be unaware that HCM is present. Onset of symptoms often coincides with the rapid growth and develop‐ ment of late childhood and early adolescence. The strenuous exercise of competitive sports has also been known to make symptoms of HCM more apparent. Disease severity and symptoms are related to the extent and location of the hypertrophy and whether there is obstruction to blood leaving the heart or valve leakage from the left-sided pumping chamber

diagnosed or have symptoms.

**5.1. Signs and symptoms of HCM**
