Myocardial fibrosis is a condition that involves the impairment of the heart's muscle cells called myocytes. It belongs to a class of diseases collectively known as fibrosis, which denotes hardening or scarring of tissue. This is a condition that not only affects the heart, but also other organs such as the lungs and liver. Myocardial fibrosis is also referred to by the more general term of cardiac fibrosis.
Myocytes, which come from originating cells called myoblasts, are instrumental in controlling the heart rate by producing electrical impulses. Each myocyte cell has a collection of cylindrical filaments called myofibrils. These are the cell units that enable the heart to contract. Normally, myocytes form lines of cells in the heart.
In myocardial fibrosis, myocytes are replaced by tissue that is unable to contract. This happens when fibroblasts, which produce collagen to enable wound healing, provide excessive amounts of the protein. This results in a case of abnormal scarring, or fibrosis. This process hardens the heart, thus making it inflexible.
This condition usually affects the ventricles, which are the heart's pumping chambers. Its symptoms include chest pain, some abdominal swelling, nausea and fatigue. This usually indicates an array of heart problems, with progressive heart failure being a prime example. Other problems include accelerated heart rate, or tachycardia, and arrhythmia, the irregular electrical activity of the heart due to the loss of myocytes.
The myocardial heart condition is particularly common in Africa's subtropical regions. It is most severe in countries like Nigeria, where myocardial fibrosis is one of the leading causes of adult heart disease and the culprit in about a quarter of heart-failure cases in children. Other African countries similarly affected include Uganda and Mozambique. It is also especially prevalent in other substantially equatorial regions in the Indian subcontinent and South America.
No official cause has been established for myocardial fibrosis. Additionally, the disease is generally thought to be irreversible. Patients tend to have the condition at an advanced stage when diagnosed, since the symptoms are not particularly distinctive. This results in short survival rates. Most patients with this condition die within two or three years.
Despite the limited knowledge and poor prognosis of myocardial fibrosis, some progress has been made regarding the disease. For example, some researchers have suggested infections from diseases such as malaria, high-fiber diets and inflammation as causes. Also, it is suggested that certain proteins could reverse the hardening process by decreasing the development rate of fibroblasts, which ultimately can restore the heart's flexibility.