Dilated Cardiomyopathy

Symptoms

When the left ventricle is enlarged and unable to pump enough blood to the body, the body reacts by reducing blood flow to parts of the body. This leads to the following symptoms:

• Pallor – The skin may appear paler than usual because the blood vessels near the skin surface constrict, allowing blood to go to the vital organs preferentially.
• Fast heart rate – The heart beats faster to deliver more blood to the body.
• Arrhythmia – The sick heart may create abnormal heart rhythms, some of which may be life-threatening.
• Shortness of breath with exertion/fatigue – As the heart’s lower left chamber (left ventricle) fails to pump blood out to the body effectively, proper blood flow through the other heart chambers and the blood vessels from the lungs to the heart is restricted. Fluid may build up in the lungs, making it through the other heart chambers. Blood vessels from the lungs to the heart are restricted, making oxygenation more difficult. The skin may become cool and wet due to sweating (diaphoretic).
• Leg swelling – Fluid may build up in the legs.
• Poor appetite and failure to grow properly – Because of the extra calories used by the heart and body to struggle to maintain proper blood flow, growth may be affected, particularly in babies.

Progression and possible complications

If caused by a virus, cardiomyopathy may improve on its own. Medications may help the heart undergo this healing process. If it does, the child can lead a normal life thereafter. It’s believed that about one-third of patients with DCM get better, one-third stay the same with reduced heart function, and one-third experience a severe deterioration. Cardiomyopathy related to muscular dystrophy or a metabolic cause generally is progressive, and when cardiomyopathy becomes evident after chemotherapy treatment for cancer.

In addition to reducing the heart’s ability to deliver sufficient blood to the body, the stretched and scarred heart muscles caused by cardiomyopathy may lead to abnormal heart rhythms, some of which may be life-threatening. Because of the sluggish blood flow created by the weakened pumping action of the heart, blood clots may develop within the heart, which are dangerous because they can break loose, travel through the bloodstream, and lodge in the brain or lung, thereby blocking blood flow and leading to a stroke or death.

As the heart enlarges, the valves may become stretched, resulting in leakage. This leakage can place additional strain on an already sick heart. The weak heart has difficulty pumping blood to the body, and it may send blood backward through the valve that sends blood into the ventricle (mitral valve), known as mitral valve regurgitation.

As the heart becomes sicker, not only is the squeezing/pumping (systolic) action impaired, but the ability of the heart to relax to suck blood into it for the next pumping cycle suffers, which is known as diastolic dysfunction. If leakage of the mitral valve worsens, this further impairs the ability of the heart to relax between pumping cycles. The heart becomes stiffer, and blood backs up into the lungs, resulting in congestion of the lungs and impairment of oxygenation of the blood. Furthermore, a backup in blood pressure places additional stress on the lungs and can lead to the development of pulmonary hypertension.