<qa>  What is the ejection fraction of the left ventricle?- unstable coronary artery disease, ejection fraction of the left ventricle of 40 or less, heart valve defect that dictate specific treatment, condition after valve replacement, heart rhythm disorders, the presence of a permanent pacemaker, contraindications to exercise, inability to perform exercise testing, mental retardation, severe anemia, obstructiverestrictive lung disease severe degree, recent thrombo embolic events, age over 80 years. 