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A 45-year-old man with dyspnea on exertion and peripheral edema is diagnosed as having congestive heart failure. There is no evidence of coronary artery disease by angiog-raphy, and his ejection fraction is 25%. The patient is advised to restrict his dietary sodium and to weigh himself every day. An angiotensin-converting enzyme inhibitor is initiated and uptitrated to tolerance. Digoxin and a diuretic are also prescribed. His dyspnea resolves, but he remains slightly fatigued on exertion.
On physical examination, his pulse rate is 76/min and regular, and his blood pressure is 100/70 mm Hg. Jugular venous pressure is 6 cm H2O. His chest is clear. An S4 is heard. There is no evidence of peripheral edema. An exercise test with gas exchange is ordered. The patient walks for 6 minutes using a low-level protocol and stops because of fatigue. His pulse rate increases to 130/min and his blood pressure to 130/70 mm Hg. Peak oxygen uptake is 20 mL/min/kg with an adequate effort, but with only walking 10 minutes. No arrhythmias are noted during the test. The patient would like to increase his activity level but has been told by another physician that he should rest and remain relatively inactive.
Which of the following should you recommend to the patient regarding his physical activity?
(A) He should limit his activities to a very low level.
(B) He should limit his activities until his volume status stabilizes.
© He may increase his activities commensurate with, but not exceeding, his exercise tolerance.
(D) He should begin a carefully prescribed exercise program.
(E) He should adjust his activities to avoid fatigue, since the fatigue is related to a low cardiac output.
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ANSWER IS D
This patient has improved symptomatically, and his physical examination has not shown any evidence of volume overload. Furthermore, the resting ejection fraction has no relationship to exercise capacity. Therefore, one cannot predict activity tolerance with resting indices of ventricular function. A peak oxygen uptake of 20 mL/min/kg is associated with a good 1-year prognosis. His blood pressure rose during exercise, indicating an increase in cardiac output with exercise. Therefore, his fatigue is probably related to deconditioning and not to heart failure.
Traditionally, patients with heart failure were encouraged to rest and avoid physical activity. However, recent studies have proved that physical activity should be strongly encouraged, rather than avoided. Heart failure, in itself, can be debilitating, and bed rest can lead to deconditioning. In addition, patients with longstanding heart failure have skeletal muscle wasting and changes in muscle fiber composition that enhance activity intolerance. Rehabilitation programs for these patients have successfully improved functional capacity with an acceptable risk. In 1995, the Agency for Health Care Policy and Research published cardiac rehabilitation guidelines that recommend exercise for patients with impaired ventricular function. Physiologic improvements from exercise include an increase in peak oxygen uptake, improved peripheral oxygen extraction, and an increase in the peak early filling rate. Asking this patient to limit activity only to his current tolerance will hinder his ability to improve. An exercise program needs to be carefully constructed by an experienced rehabilitation team and should include resistive training in addition to aerobic activities. The minimum amount of exercise needed to effect improvements in functional capacity has not been definitively established. One recent study has shown improvement in exercise capacity in patients with heart failure when even a low-level exercise program was undertaken. Unfortunately, few clinicians refer patients to rehabilitation programs, although their beneficial effects and safety are clearly evident.
A reasonable exercise program can be derived from results of a baseline exercise stress test, with or without gas exchange measurements. In general, aerobic activity of 20 to 30 minutes, duration three times a week at an intensity commensurate with 60% to 80% of peak capacity or a rate of perceived exertion of 13 to 15 on the Borg Scale is recommended. However, if a patient is unable to exercise for 20 minutes, shorter segments can be started and gradually increased to tolerance. Similarly, if an intensity of 60% to 80% of peak capacity is not possible at the outset, a lower intensity is advised with gradual increases. Most important, continued activity should be recommended. Whether aerobic exercise will improve mortality in the long-term still needs to be determined.
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l, aerobic activity of 20 to 30 minutes, duration three times a week at an intensity commensurate with 60% to 80% of peak capacity or a rate of perceived exertion of 13 to 15 on the Borg Scale is recommended.
