The most common causes of right ventricle hypertrophy (RVH) are diseases that damage the lung like emphysema and cystic fibrosis. These diseases destroy blood vessels in the lung, causing increased pressure in the remaining vessels. Conditions that decrease oxygen levels, such as chronic bronchitis and sleep apnea, also lead to RVH. Stenosis of the pulmonic heart valve, repeated blood clots to the lungs (chronic pulmonary embolism), and primary pulmonary hypertension are a few of the remaining causes of RVH.
What causes cardiac dilation?
The most common causes of dilation are conditions that directly damage the heart muscle. The heart’s healing response is a thinning and stretching-out of the muscle. Types of damage include prior heart attack, long-term alcohol abuse, and heart muscle inflammation. Heart muscle inflammation, or myocarditis, is sometimes of unknown cause and is often associated with a viral infection or interaction between the immune system and the heart muscle. This immune reaction can be seen with inflammatory diseases like lupus or toward the end of pregnancy (approximately 1 in 4000 chance). Other sources of damage to the heart muscle, which can lead to dilatation, include:
- Some types of cancer chemotherapy
- Excess iron accumulation in the body from the disease hemochromatosis
- Cocaine use
- Several of the anti-viral medications used to treat HIV
- Some of the older medications to treat schizophrenia
- Exposure to metals like cobalt, lead, and mercury (an important consideration for those who work in manufacturing processes that includes exposure to these metals)
Cardiac dilation may also be associated with thyroid disease. There is a genetic form of dilated cardiomyopathy, related to many of the several forms of muscular dystrophy; in these, the disease process which affects and weakens body muscle does the same to the heart muscle. Finally, problems with the heart valves can cause abnormal cardiac dilation. In situations where the heart valves cannot fully close, a condition called valvular regurgitation, a backflow of blood with each heartbeat stretches out a chamber of the heart (typically the left atrium or left ventricle), causing it to dilate over time.