Myocarditis is an inflammation of the heart muscular tissue. Principal triggers of this illness are viruses (up to 50 percent), but bacteria, protozoa, parasites and funguses may also be the cause. These agents can gain access to the body in the guise of a variety of infectious disorders and in this way attack the heart muscle. A person whose immune system is weakened has an increased risk of myocarditis,as infectionscan more easily spread to the whole body and therefore also affect the heart. Low immunity can, for example, be the result of an AIDS illness, or taking medication which weakens the immune system. Such medication is applied, for example, after an organ transplant to prevent the body rejecting the donor organ.

Dilation means extension or enlargement. Dilated cardiomyopathy is an illness of the heart muscle in which the ventricles and the atria of the heart become enlarged. At the same time the pumping capacity of the heart is reduced. This leads to an insufficient supply to the organism and to indications of heart weakness (cardiac insufficiency)

Dilated cardiomyopathy (DCM) is the most frequent form of heart muscle disease. For every 100,000 inhabitants there are 6 new illnesses each year, and men are affected twice as often as women. This is particularly true for types of dilated cardiomyopathy with no recognizable original cause. This form of DCM is also called idiopathic (without recognizable cause) dilated cardiomyopathy. One possible trigger for dilated cardiomyopathy is a suspected viral infection, as examinations show that many affected people have inflammatory infiltrates in the heart muscle. In addition, in many patients there is a significant increase in the production of immunglobulines of the IgG (antibody) type, which points to an activation of the immune system through a causative agent

Hypertrophic cardiomyopathy (HCM) is a genetically conditioned disorder affecting the heart muscle which causes a thickening of the wall or musculature of the left ventricle. The consequence of this is that the coronary arteries can no longer supply the thickened muscle with sufficient oxygen and the muscle is unable to pump enough blood into circulation. There are two distinguishable types:

• hypertrophic obstructive cardiomyopathy (HOCM) - with a narrowing of the left ventricle
• hypertrophic non- obstructive cardiomyopathy (HNCM)  - with no narrowing of the left ventricle

The ischemic cardiomyopathy is a dilative cardiomyopathy which is caused by chronic insufficient oxygen supply of the heart muscle.