And those are just diagnosed cases. What about missed diagnoses or conditions that display no symptoms at all?
A review of sudden unexpected cardiac death (SUCD) in children found that three causes are the most common: myocarditis, hypoplastic left heart syndrome and dilated cardiomyopathy.
Following is everything you need to know about these cardiac conditions.
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1. Myocarditis
Myocarditis occurs when inflammation and heart muscle damage are present. Causes include viral infections, autoimmune disorders, adverse medication reactions and environmental toxins, according to the Myocarditis Foundation.
This condition, along with its associated condition, idiopathic dilated cardiomyopathy, results in about 45 percent of the heart transplants that take place in the United States.
The most frequently experienced symptom of myocarditis is shortness of breath during physical activity. If you’ve heard of the rare story of an athlete suddenly dying of a cardiac condition, it may have been due to myocarditis.
Shortness of breath usually occurs a week to two weeks after a viral illness, like a severe cold or flu, resulting in difficulty sleeping.
Other symptoms can include fatigue, heart palpitations, and chest pain or pressure. In addition, leg swelling may occur. And in rare cases, abnormal heart rhythm may cause a sudden loss of consciousness.
To diagnose this condition, a doctor will perform an electrocardiogram, in which electrodes are put on the skin to examine heartbeats. It’s a simple, quick procedure.
Further, professionals will conduct an echocardiogram that involves sound waves that an image of the heart and analyze blood flow. And he or she will probably get a chest x-ray to look at the size and shape of the heart.
That brings us to an important question: How is myocarditis treated?
According to the Myocarditis Foundation, doctors use medications used to treat heart failure. Steroids, rest and a low-salt diet also might be prescribed to reduce inflammation. However, abnormal heart rhythms may require surgery to install a pacemaker or defibrillator.
The good news is that lots of people recover from this condition. But in some cases, heart function may not improve after a bout of myocarditis. Sufferers may require long-term medical therapy and sometimes heart transplants.
2. Hypoplastic Left Heart Syndrome
Hypoplastic left heart syndrome (HLHS) is a congenital condition.
The Centers for Disease Control and Prevention (CDC) describe HLHS as a birth defect that affects normal blood flow in the heart. This occurs when the left side of the heart does not form correctly during pregnancy.
Five variations can occur in the case of HLHS:
- The left ventricleis underdeveloped and too small.
- The mitral valvesare malformed or are very small.
- The aortic valveis malformed or very small.
- The ascending portion of theaortais underdeveloped or is too small.
- Often babies with hypoplastic left heart syndrome also have anatrial septal defect, which is a hole between the left and right upper chambers (atria) of the heart.
Treatments for the condition may include medication, nutritional intervention (like a feeding tube) and surgery.
According to the CDC, multiple surgeries are required soon after birth to increase blood flow and bypass the poorly functioning heart's left side. These treatments help restore heart function but are not a cure.
Surgeries are done in three phases. The first is called a Norwood Procedure. According to the CDC, the surgery is done within the first two weeks of a baby’s life. Surgeons create a "new" aorta and connect it to the right ventricle. They also place a tube from either the aorta or the right ventricle to the vessels supplying the lungs (pulmonary arteries).
The second surgery is called a Bidirectional Glenn Shunt (BDG) procedure and is performed when the infant is four to six months old. This procedure creates a direct connection between the pulmonary artery and the vessel (thesuperior vena cava), returning oxygen-poor blood from the upper part of the body to the heart. It lessens the workload on the right ventricle by facilitating blood flow to the lungs.
The third surgery is called a Fontan procedure and is performed at 18 months to three years of age. Doctors connect the pulmonary artery and the vessel (the inferior vena cava), returning oxygen-poor blood from the lower part of the body to the heart and directing the rest of the returning blood to the lungs. Once this procedure is complete, oxygen-rich and oxygen-poor blood no longer mix in the heart, removing the bluish pallor from an infant's skin.
These procedures are not cures, so complications may continue throughout a child’s life. And in some cases, a heart transplant may be needed.
3.Dilated Cardiomyopathy
According to Cincinnati Children’s Hospital Medical Center, dilated cardiomyopathy (DCM) affects the heart muscle, which becomes thin. The left ventricle (lower left chamber of the heart) becomes enlarged (dilated), and the heart is unable to squeeze efficiently, reducing the amount of blood pumped to the body.
The problem with DCM is that it is often symptomless. However, older children who are in heart failure can experience shortness of breath, fatigue, dizziness or light-headedness, fainting, cough, and weight gain or swelling. In newborns, symptoms will come in the form of trouble feeding the child, a lack of growth, sweating during feeding or active times, fussiness, and rapid breathing.
DCM is most commonly caused by myocarditis, which is why it’s considered an associated condition. However, it also can be caused by chemotherapy and metabolic diseases. That’s what is referred to as idiopathic DCM.
To diagnose DCM, thorough cardiac testing is performed. According to Cincinnati Children’s Hospital Medical Center, an echocardiogram is the most common test used to diagnose DCM. It measures the dilation of the ventricle and overall squeeze of the heart. Other tests may include bloodwork, an electrocardiogram (EKG), an exercise stress echo test, cardiac catheterization and magnetic resonance imaging (MRI).
Doctors will ask for a family and medical history. This is an important step. “A family tree should be constructed with specific attention to a history of cardiomyopathy, rhythm problems, sudden cardiac or unexplained death, cardiac surgery or presence of other cardiac disease in relatives,” according to Cincinnati Children’s Hospital Medical Center.
A myocardial biopsy may be performed in the cardiac catheterization laboratory to help determine the cause. A tiny instrument will be inserted into the heart via a vessel in the leg, and a tissue sample will be taken from the heart, examined under a microscope and tested for viruses to help to determine the cause of the cardiomyopathy.
In addition, genetic tests may be run. This type of testing is done with a blood sample. It is best to begin genetic testing in a family with an individual who is known to have cardiomyopathy. If a gene mutation is found in someone with that type of cardiomyopathy, genetic testing for the same mutation can be offered to close family members. Finding a gene mutation in other family members will help identify family members who may be at risk to develop heart muscle disease and who should have cardiac screening, reports Cincinnati Children’s Hospital Medical Center.