An enlarged heart is not a major disease on its own, but it is a precursor to stronger serious diseases. It is a symptom, a warning that something is not right and preventive car must be taken to prevent permanent damage from occurring. The heart can not remain enlarged as it is vulnerable in the malformed condition. The heart's new form leaves it unable to perform its basic function.
Stress
The heart is a muscle like any other in the body. Just like the muscles of the arms hypertrophy and grow with stimulation, such does the heart. If a person performs intense exercise to excess, the heart responds by growing in size to meet the need. Although beneficial to exercise, it is not beneficial to rest. Blood travels slowly through a large heart and blood clots may form. Murmurs may form due to the new shape of the heart. Be careful to watch your heart rate while exercising.
Nutrition
Exercise is not the only cause of an enlarged heart. High blood pressure and too much cholesterol also cause the heart to work harder during exercise and even at rest. Work with a dietitian or physician pair to develop a nutritional plan to lower blood pressure and cholesterol so that your heart never has to work harder than it should at any given time.
Barth Syndrome
Perhaps your nutrition is fine and you do not over work yourself but your heart is still enlarged. Barth syndrome is a genetic disease found in male children and typically goes unnoticed for most of life. However, these individuals typically are of shorter stature and catch bacterial infections rather easily. A clinician will be able to run tests to tell if the disease was inborn in you or caused by stimuli of some sort.
Other Diseases:
Many other diseases come into contact with the heart through blood, affecting the heart in some way or another. This can act as a stress on the heart, causing it to increase in size. With treatment of the disease, the heart can return to normal size.
