Cardiac abnormalities have many causes including structural defects, electrical conduction problems, and infectious processes. Although some cardiac abnormalities can occur at any time of life, many are present at birth. The American Heart Association reports that congenital cardiac abnormalities are present in up to 1.3 million Americans. Some defects are mild, or they are successfully treated with surgery. Others are very serious, leading to disability and reduced quality of life.
Atrial Septal Defect
The heart has two upper chambers called the atria. An atrial septal defect is a hole in the tissue that separates the two chambers. This causes blood to flow from the left atrium to the right atrium, when it should flow from the left atrium down into the lower left chamber, or ventricle. This opening between the two atria is normally present at birth, but begins to close during the first few weeks or months of life. In some babies the hole is larger than normal or does not close properly.
A small hole may cause no symptoms at all and might never be discovered. Larger holes are generally diagnosed and repaired in early childhood. If the defect is not repaired, it can eventually lead to heart and lung damage later in life. Symptoms may include shortness of breath during exercise, rhythm problems, blood vessel damage in the lungs and stroke.
Mitral Valve Prolapse
The mitral valve consists of two tiny flaps located between the left atrium and left ventricle of the heart. Normally these flaps, or cusps, close tightly to prevent blood from flowing back into the left atrium when the ventricles contract. In mitral valve prolapse, the cusps do not open and close properly. Instead, they flop back into the left atrium, allowing blood to leak back through. This condition is caused by a weakening of the valve tissue and of the chords that attach the valves to wall of the ventricle. Mitral valve prolapse may have a genetic component.
People with mitral valve prolapse are often unaware of their condition. Some may experience chest pain, shortness of breath, faintness and heart palpitations. Mitral valve prolapse can result in a condition called mitral regurgitation, or MR, according to Merck Manuals Medical Library. If MR is severe it can cause heart enlargement, rhythm problems or stroke. Mitral valve prolapse without MR generally requires no treatment.
Dilated Cardiomyopathy
Dilated cardiomyopathy is a condition in which the heart muscle becomes enlarged and weakened, making it difficult for the heart to pump blood effectively. As the condition progresses, the walls of the heart become more thin and the chambers more dilated. Dilated cardiomyopathy can lead to heart failure, a serious condition resulting in fatigue, shortness of breath and swelling of the legs and ankles.
Dilated cardiomyopathy can have multiple causes. The National Heart, Lung and Blood Institute reports that many cases of the disease are inherited from a parent. Other causes include coronary artery disease, thyroid disease, diabetes, alcohol and certain viral infections. Some medications can also contribute to the development of dilated cardiomyopathy.
