Many general diseases affect the heart and can be classified according to the part of the heart affected or the nature of the changes produced. Inflammatory infections are divided into pericarditis, myocarditis, and endocarditis. Valvular diseases are one of the most important groups in which any of the four valves may be stenosed; associated with this group are hypertrophy in which the heart is enlarged, and dilation, in which one or more of the cavities is dilated. Degeneration of the muscular tissue may take place in the direction either of a fatty or, less commonly, of a fibroid change. There is also a class of functional disorders in which palpitation, irregularity, rapidity, slowness or even severe attacks of pain appear. If the defect of the heart be so great that it must be remedied by compensation, the pumping power of the heart weakens and symptoms appear either to the heart itself (pain and palpitation) or to other organs - for example: breathlessness, faintness, dyspepsia, swelling of the abdomen, dropsy of the feet.