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• Symptoms of Heart and Blood Vessel Disorders
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Heart disorders can limit a person's ability to perform physical activities. One way to evaluate the severity of a heart disorder is to determine how limited this ability is. Doctors may use the New York Heart Association (NYHA) functional class system to make this evaluation. In mild disease (class I), ordinary physical activity may not be limited. In moderate disease (class II), ordinary activity causes symptoms, and in moderately severe disease (class III), less-than-ordinary activity causes symptoms. In severe disease (class IV), symptoms occur during rest, and any physical activity makes them worse. However, this system is not foolproof, because even serious heart disorders may produce no symptoms if people reduce their activity level to compensate for the disorder.

Last full review/revision April 2006 by Paul H. Tanser, MD