cardiovascular rehabilitation: status, 1990

Cardiovascular Rehabilitation: Status, 1990

RAY W. SQUIRES, Ph.D., GERALD T. GAU, M.D., TODD D. MILLER, M.D., THOMAS G. ALLISON, Ph.D., CARL J. LAVIE, M.D.,* Division of Cardiovascular Diseases and Internal Medicine

Cardiovascular rehabi l i tat ion is def ined as the process of deve lopment and maintenance of a desirable level of physical , social , and psychologic funct ioning after the onset of a cardiovascular i l lness . Pat ient educat ion, counsel ing, nutrit ional guidance, and exerc ise tra ining play prominent roles in the process of rehabil itation. Benef i ts from cardiac rehabi l i tat ion include improved exercise capacity and decreased symptoms of angina pectoris , dyspnea, c laudicat ion, and fatigue. Recent pooled data regarding exerc ise tra ining after myocardial infarction demonstrated a 20 to 25% reduct ion in mortal i ty and major cardiac events . Exercise training may result in an improvement in systemic oxygen transport, a reduct ion in the myocardial oxygen requirement for a g iven amount of external work, and a decrease in the extent of myocardial i schemia during physical activity. The efficacy of modiflcation of risk factors in reduc ing the progress ion of coronary artery disease and future morbidity and mortal i ty has b e e n establ ished. Herein w e rev iew the history, current practice and results , and future chal lenges of cardiovascular rehabil i tation.

Cardiovascular rehabilitation has become an accepted component of patient care after acute myocardial infarction, cardiac surgical procedures, and other cardiovascular disorders. It is the process of development and maintenance of a desirable level of physical, social, and psychologic functioning after the onset of a cardiovascular i l lness. ' In the broad sense, almost all types of treatment for cardiovascular disease ass ist in rehabilitation. Specifically, education, counseling, nutrition, and exercise training are combined in classic cardiac rehabilitation to assist patients in returning to a near-normal

*CuiTent address: Ochsner CHnic and Alton Ochsner Medical Foundation, New Orleans, Louisiana.

Individual reprints of this article are not available. The entire Symposium on Myocardial Ischemia will be available for purchase as a bound booklet from the Proceedings Circulation Office in June.

life-style as soon as possible after recognition of the disease or in adapting to the limitations imposed by the disease. ' Specific goals of rehabilitation include risk stratification, limitation of potential adverse psychologic and emotional consequences of cardiovascular disease, modification of risk factors, reduction of morbidity and mortality, alleviation of symptoms, and improvement of function." For coronary artery disease, the potential retardation or reversal of the disease process with the objective of decreasing the probability of future clinical manifestations is an important, if not yet proven, goal. This is a particularly important goal because most patients who have had a myocardial infarction will eventually die as a direct result of their coronary artery disease.

H I S T O R I C A L P E R S P E C T I V E Although some efforts at rehabilitation of cardiac patients were begun in the 19308,* part of

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732 CARDIOVASCULAR REHABILITATION Mayo Clin Proc, May 1990, Vol 65

the usual treatment for acute myocardial infarction until the 1950s included 6 weeks of strict bed rest. This corresponded to 2 t imes the assumed heal ing t ime for the damaged myocardium.'' This period of drastically reduced activity resulted in a substantial diminution in cardiovascular functional capacity (cardiovascular fitness) because of both deconditioning of the myocardium and skeletal muscle and loss of vasomotor reflexes.' In 1951, Levine and Lown* advocated early mobilization, which included progressive periods of sitt ing upright in an armchair. They reported that this "armchair treatment" resulted in a considerable decrease in morbidity and mortality in comparison with the standard treatment practice. Later in the same decade, detailed programs of physical activity for inpatients were formalized."

In the 1960s, with the proliferation of coronary-care units and continuous electrocardiographic monitoring, progressively earlier mobilization after acute myocardial infarction was practiced. Some patients with healed myocardial infarctions were found to have an exercise capacity comparable to that of normal age- and sex-matched patients. Investigators realized that the measurable physical impairment after an uncomplicated myocardial infarction was less than was previously thought.*"" The presumption of emotional and physical invalidism invariably occurring after a coronary event was found to be in e r r o r . R e h a b i l i t a t i o n was dominated by aerobic exercise training and included some vocational readjustment.

During the 1970s, the multidimensional aspects of cardiovascular rehabilitation were acknowledged, established methods were developed, and the team approach was promoted.*^ Risk factor concepts emerged from the epidemiologic literature, and guidelines for cardiac exercise programs were established.'^*" Rehabilitation, including efforts at secondary prevention, gained widespread support as an integral component of comprehensive cardiology.

The need for cardiac rehabilitation services is supported by data that suggest that 20% of patients who have suffered a myocardial infarction have some type of perceived disability.*^ In

one large study,* only 63% of patients younger than 65 years of age remained in the work force 1 year after having an infarct. Even fewer patients who have undergone a coronary artery surgical procedure return to work than the percentage of those who have had an uncomplicated myocardial infarction.*' The need to modify traditional cardiovascular risk factors and use judicious medical and surgical therapy is apparent because of the progressive nature of coronary artery disease. Approximately 55% of patients who undergo coronary artery bypass grafting have progressive atherosclerosis that occludes at least one saphenous vein graft within 10 years after the operation.'*

A D M I N I S T R A T I V E A S P E C T S The components of the rehabilitation program must be individualized and are most efficiently determined and provided by use of the collective skills and experience of a variety of health-care professionals (Table 1). The primary patient population that may benefit from cardiovascular rehabilitation consists of selected patients with cardiovascular disease such as acute myocardial infarction, angina pectoris, cardiac operations (for example, bypass grafting, percutaneous coronary angioplasty, valve repair or replacement, valvuloplasty, correction of congenital abnormalities, and cardiac or cardiopulmonary transplantation), cardiomyopathy, peripheral vascular disease, hypertension, or angiographically demonstrated but silent disease. Additional patient subgroups may benefit

Table 1.Potential Team Members for Cardiac Rehabi l i tat ion Programs

Primary physician Nurse coordinator Cardiologist Physical therapist Surgeon Occupational therapist Psychiatrist Dietitian Physiatrist Cardiac rehabilitation Exercise physiologist nurse Psychologist Primary nurse Pharmacist Head nurse Social worker Exercise specialist Vocational rehabilitation Smoking cessation

counselor counselor

Mayo Clin Proc, May 1990, Vol 65 CARDIOVASCULAR REHABILITATION 733

from exercise training, renal dialysis, renal or renal and pancreatic transplantation, liver transplantation, and other rehabilitative efforts for pulmonary disease, obesity, diabetes mell itus, anxiety and depression, neurologic problems (stroke, spinal cord injury), cancer, or drug dependency.

Most patients have the potential to benefit from the instructional aspects of rehabilitation, such as information about the acute event, medications, diet, cessation of smoking, management of stress, and psychosocial adjustment. Nurse-directed group discussions are helpful for all patients as well. The exercise portion of the program is restricted to patients who have no unresolved absolute contraindication to exercise training (Table 2).

I N P A T I E N T R E H A B I L I T A T I O N The rehabilitative process for the cardiac patient has been arbitrarily divided into four phases (Table 3). The period of hospitalization (inpatient rehabilitation) is designated phase I. During this period, individual patient needs must be addressed; family members and significant others should be included in the process of rehabilitation. Program components include controlled low-level exercise, patient and family education, group and individual counseling, and group discussion sessions. Patient education is particularly important after a cardiac event because patients who understand their disease and the rationale for its management are more likely to follow recommendations for their care.'" The objectives are diverse: (1) to prevent potential deleterious effects of prolonged bed rest; (2) to hasten adjustment to the hospital environment and the acute event; (3) to begin risk

stratification; (4) to begin identification and modification of risk factors; (5) to facilitate return to physical activity and thereby reduce the feeling of invalidism; (6) to provide medical surveil lancethat is, to determine the appropriateness of psychologic adaptation and the hemodynamic and electrocardiographic responses to exercise; and (7) to maintain neuromuscular relaxation.

The usual psychologic responses of a patient to an acute cardiac event have been described.'"" Panic and anxiety surface during the first hours after myocardial infarction. Precipitating factors include the stress of i l lness, unfamiliar surroundings, the threat of death, and discomfort. Depression, probably related to a feeling of loss of physical ability or potential as an individual, may occur as early as 3 days after the event or during the early outpatient phase of recovery. The depression is usually transient and may be characterized by typical somatization complaints of fatigue or nonspecific discomfort. The group discussions in the hospital, led at our institution by specially trained nurses, provide important psychologic support and counseling. Denial is common and may constitute a beneficial response (that is, complete acceptance of the illness but denial of its seriousness) or may be manifest by complete rejection of the reality of the i l lness. Beneficial denial is associated with a high potential for rehabilitation and a favorable outcome." Careful education and encouragement are generally all that is necessary, with particular emphasis on the normal psychologic reaction to a cardiac event as well as stress education and relaxation training.

Sexual function should be addressed early during rehabilitation. Data suggest that the

Table 2.^Absolute Contraindicat ions to Exercise Training

Unstable angina pectoris Dangerous arrhythmias Overt cardiac failure Severe obstruction of the left ventricular

outflow tract Dissecting aneurysm Myocarditis or pericarditis (acute)

Serious systemic disease Thrombophlebitis Recent systemic or pulmonary embolus Severe hypertension Overt psychoneurotic disorders Uncontrolled diabetes mellitus Severe orthopedic limitations


Table 3 .Phases of Cardiac Rehabi l i tat ion

Phase Type of program Duration

I Inpatient Days II Outpatient, immediately 2-12 wk

after hospitalization III Late recovery period Minimum of 6 mo

beyond phase II IV Maintenance Indefinite

frequency of intercourse is reduced for many months after myocardial infarction and coronary bypass grafting procedures in most patients and that sexual dysfunction is common-^^-^* Individual counseling with the patient and partner in terms of the "energy cost" of intercourse and the recommended t ime frame for resumption of sexual activity is helpful. Exercise test ing and training are helpful in increasing patient and partner confidence and sense of well-being. In general, peak rates of energy expenditure during intercourse are less than 5 mets (metabolic energy equivalents)for example, equivalent to climbing one to two flights of stairs (1 met = resting energy expenditure equivalent to 3.5 ml of O^/kg per min).^'^ Most patients are able to return to sexual activity by the third week after the event. Male patients taking -adrenergic blockers may experience impotence, which can easily be reversed by altering the medical regimen. Patients who experience angina pectoris during intercourse may benefit from taking nitroglycerin before intercourse.

The physical activity program follows a step-by-step written protocol (Table 4). A step is defined as a specific activity level, and patients typically advance one step each day. Exercise guidelines are similar for all patients and are conservative in intensity and duration. At our institution, three stages of activity are identified. Stage one begins when the patient is hemodynamically and electrically stable in the intensive-care unit. This stage commences with passive range-of-motion exercises and sitting at the bedside and in an armchair to maintain vasomotor reflexes that prevent orthostatic hypotension. During stage II, the patient gradually assumes self-care activities, supervised

walking, and active range-of-motion exercises. An upper limit heart rate of 20 beats/min above the rate for standing at rest is used. Stage III activity includes progressive slow ambulation (1 to 2 mph) for up to 10 minutes three t imes daily, supervised by a physical therapist. Limited stair climbing is also performed. Throughout stage III, the patient dresses in street clothes. The hemodynamic and electrocardiographic responses to early inpatient low-level exercises have been acceptable.^ Heart rate responses for active range-of-motion exercises and ambulation are between 5 and 15 beats/min above resting levels. The typical systolic blood pressure response is 4 to 14 m m Hg above the resting level. Complications are rare.^' Early and rapid mobilization after uncomplicated myocardial infarction does not increase infarct size or decrease left ventricular ejection fraction.^*

A predismissal or early postdismissal graded exercise test , with use of either a standard rehabilitation treadmill protocol or a nuclear cardiology procedure (radionuclide angiography or thallium perfusion study), is helpful in risk stratification and home activity prescription. Test endpoints usually include an energy expenditure of 5 to 6 mets or signs and symptoms of ischemia or exercise intolerance. A home exercise program is provided and discussed with the patient before dismissal from the hospital. Guidelines for graduated general physical activity are also provided (Table 5).

The short-term benefits include the following factors: (1) reduction in orthostatism, impaired physical work capacity, thromboembolism, reduced joint range of motion, and hypoventila-tion;''^" (2) improved psychologic status during convalescence;^"'^" (3) potential earlier return to previous activities and work;^' (4) potential reduction in duration of hospital stay; and (5) increased patient sense of well-being.

Long-term benefits of inpatient cardiovascular rehabilitation are questionable. Evidence supports the fact that habitual exercise after hospitalization is greater in phase I participants than in nonparticipants,^^ but risk factor status and subsequent morbidity and mortality are unaffected.'*"


Table 4.Mayo Clinic Inpat ient Cardiac Rehabi l i tat ion Physical Activity Protocol

Days of program

Stage 6-day plan

9-day plan

12-day plan Activity schedule

II

2

2 3

3 4

III

5

6

6

7

8

9

8

9

11

12

Use bedside commode. Begin physical therapy range-of-motion exercises to each extremity. Sit at side of bed 5-10 min

Sit in chair 5-15 min twice daily. Begin education program at bedside. Continue physical therapy as above

Sit in chair up to 30 min twice daily. Continue physical therapy as above

Move to step-down area. Bathe above waist, shave, and comb hair. Begin self-exercise program with physical therapy supervision. Sit in chair 60-120 min twice daily

Continue self-exercise program with physical therapy supervision. Begin ambulation with physical therapist. Sit in chair 90-150 min twice daily. Begin attending education classes and discussion groups

Take wheelchair shower and use bathroom ad lib. Continue physical activity as above

Move to general cardiovascular ward. Dress in street clothes if desired. Be up and around room as tolerated. Begin climbing stairs with physical therapist

Take predismissal graded-exercise test. Continue physical activity as above. Take standing shower

Receive final going-home instructions

The recent trend toward shorter periods of hospitahzation and more invasive procedures during the hospital stay for cardiac patients has resulted in less t ime for phase I activities. Hospital dismissal as early as 3 days after myocardial infarction has been advocated for patients with uncomplicated conditions."^ The continuation of rehabilitative services during the immediate posthospitalization period has increased in importance because of these changes and represents one of the strongest challenges for the next decade.

O U T P A T I E N T R E H A B I L I T A T I O N Outpatient rehabilitation begins at the t ime of hospital dismissal and usually involves close medical supervision for a period of weeks (phase II, Table 3). In many respects, the immediate posthospitalization period is the most critical stage of rehabilitation, in that patients are receptive to changes in life-style and are motivated by a clear recollection of the acute event. The objectives of phase II are as follows: (1) to

instruct patients in proper exercise procedures and to restore them to a desirable exercise capacity appropriate to their clinical status, life-style, and occupation; (2) to provide understanding for both the patient and the family members regarding cardiovascular disease and to continue appropriate steps for modification of risk factors; (3) to meet the psychosocial needs of pat ients and families, restore confidence, and reduce anxiety and depression; (4) to ass ist the primary physician in identifying medical problems and to provide surveillance concerning the recovery process and the effectiveness of the therapeutic regimen; and (5) to ass ist in the gradual return to occupational and avocational activities.

At our institution, education is provided by consultations with physicians, exercise physiologists, dietitians, nurses, psychologists, and other rehabilitation team members as needed. Group discussions and patient education materials are generally included. Educational topics include medications, techniques for relaxation


Table 5.Guidelines for Graduated Activity After Dismissal From the Hospital of Pat ient Who Has Had a Myocardial Infarction

W e e k l W e e k s mets ml O^/kg/min kcaVmin (70-kg person) mets ml O^/kg/min kcal/min (70-kg person) l ' /2-3 5-11 2-4

Mayo Ciin Proc, May 1990, Vol 65 CARDIOVASCULAR REHABILITATION 737

Pge. John

CARDIOVASCULAR HEALTH PROHLE MALES: aO-99 VEARS OF

CAROKWHSCULAII HEALTH GUNK MiyQCMcR

Fig. 1. Cardiovascular health profile for a 55-year-old man. The profile is used to enhance patient education and serves to motivate patients in their efforts to modify risk factors. ECG = electrocardiogram; HDL and LDL = high-density and low-density lipoproteins.

individual group participants. At the conclusion of the group meeting, participants are encouraged to identify positive changes that have evolved since their cardiac event and to try to identify a "meaning" or "message" of the event for their future lives.

Pat ients who require additional attention for emotional or psychologic i ssues are frequently identified in the support group. These persons are approached individually (often they initiate the process by approaching the group leaders themselves) , and the possibility of counseling with one of the clinical psychologists who work closely with the cardiac rehabilitation program is discussed.

Other patients in need of individual counseling are identified by a screening tool, the SCL-90R, which is given to all patients as they enter the program. The SCL-90R is a 90-item, self-

administered questionnaire that addresses 13 different categories of emotional and psychologic functioning.^' We have developed standards for assessment of the responses of patients in light of the stress of their recent cardiac event. For patients with responses outside the expected range, further discussions with a clinical psychologist or other appropriate professional are recommended. Depression and somatic anxiety are the principal reasons for referral of patients for additional individual counseling.

A standard phase II program consists of three visits per week to the rehabilitation center for supervised exercise and education. Additional home exercise sessions are usually prescribed. For patients who must travel substantial distances to the rehabilitation center and for low-risk patients, less frequent visits are scheduled. A medically supervised outpatient program of


rehabilitation provides many advantages, including close patient surveillance, expert assistance in progressing in the activity program, availability of patient education services, and social support to facilitate patient adherence to the prescribed regimen.

Dietary counseling is an extremely important aspect ofthe educational process. Depending on the patient's clinical picture, specific dietary guidelines for total fat, saturated fat, cholesterol, sodium, and caloric intake are provided by a registered dietitian."* Routine scheduled visits with the dietitian for both patient and spouse are recommended.

The exercise sessions at our medical center are supervised directly by cardiac rehabilitation nurses and exercise specialists, with physician availability. Continuous single-lead electrocardiographic monitoring and periodic blood pressure measurements are routine. Continuous electrocardiographic monitoring during exercise sessions precisely documents the heart rate, the presence of ischemia, and any arrhythmias. In our experience, electrocardiographic monitoring may be discontinued after 4 to 8 weeks for most patients. In those patients with a history of life-threatening arrhythmia or poor left ventricular function, a longer period of monitoring may be used.

Aerobic activities such as treadmill walking and cycle ergometry (forms of exercise that are easily quantifiable and reproducible) constitute the core of the supervised physical activity program at this stage of rehabilitation. Flexibility and relaxation exercises, arm ergometry, and muscle-strengthening activities including light weight training are available. Exercises for the upper extremities are important because there is little carryover in adaptive training responses from one muscle group to another."" Warm-up and cool-down activities are always performed. Initial aerobic exercise is prescribed conservatively and individually for each patientfor example, 5 to 15 minutes per session at an energy cost of 1.5 to 3.0 mets . A safe level of heart rate is derived from the predismissal graded exercise test. The prescribed exercise intensity level is below that which would produce isch

emic s igns and symptoms. In dogs in which hydraulic coronary artery occluders were inserted, repeated episodes of exercise-induced ischemia have been shown to result in cumulative deterioration of left ventricular function.''" The perceived exertion scale developed by Borg*' is used to adjust exercise intensity to a comfortable level for the patient (Table 6). The scale provides a rating of the degree of overall effort that is helpful in teaching patients proper exercise pacing.'"'*" During the first 2 to 3 weeks, the duration of aerobic exercise is increased to approximately 40 minutes while exercise intensity is maintained at moderate levels. The frequency of exercise is set at five to seven sessions per week (three or fewer at the rehabilitation center for most patients).

Home exercise activities during the first weeks of convalescence include walking, stationary cycling, and gentle calisthenics. An excellent series of exercise videotapes for cardiac patients, provided to patients only by physicians, has recently become available. Higher intensity activities such as jogging or competitive sports are inappropriate at this stage of rehabilitation. Use of the concept of mets in counseling patients is helpful (Table 7). In general, peak rates of energy expenditure should not exceed 70% of the patient's maximal capacity.

Near the completion of the phase II program, a symptom-limited graded exercise test is usu-

Table 6.Borg" Perce ived Exertion Scale

Value Description

6 7 Very, very light 8 9 Very light

10 11 Fairly light 12 13 Somewhat hard 14 15 Hard 16 17 Very hard 18 19 Very, very hard 20


Table 7.Energy Expenditure (in mets*) for Se lected Activit ies

Activity Range (mets) Desk work 1.5-2.5 Driving a car 1.5-2.5 Bench work 1.5-2.5 Bicycling 1.5-15.0 Driving a truck 2.0-3.0 Bowling 2.0-3.0 Janitorial work 2.0-4.0 Light housework 2.0-4.0 Sexual intercourse 2.0-5.0 Golf 2.0-5.0 Walking (on level surface)

2 mph 2.0 3 mph 3.0 4 mph 4.5

Dancing 2.0-8.0 Stair climbing 2.0-12.0 Light carpentry 3.0-5.0 Medium housework 3.0-5.0 Gardening 3.0-5.0 Lawn mowing 3.0-8.0 Wood chopping 3.0-10.0 Shoveling 4.0-7.0 Heavy assembly work 5.0-8.0 Heavy labor 8.0-12.0 Jogging

5 mph 8.0 6 mph 10.0 7 mph 12.0

*1 met = resting metabolic rate, 3.5 ml ofO^/kg/min.

ally performed. Depending on the clinical picture, a standard treadmill test , cycle ergometry, radionuclide angiography, tomographic thall ium study, or exercise with respiratory gas analysis is chosen. Results are used to update the exercise prescription and to determine the patient's readiness to return to work and other activities. At this point in the program of rehahilitation, the intensity of exercise i s prescribed at approximately 60 to 70% of exercise capacity and at a level below the precipitation of s igns and symptoms of ischemia. This level of exercise intensity is generally comfortable and well tolerated by most patients. Exercise at intensit ies as low as 50% of capacity has been demonstrated to improve the aerobic exercise capacity of selected

cardiac patients.** The duration of exercise continues at 30 to 45 minutes , with a minimal frequency of three sessions per week.

For selected patients, an occupational readiness assessment including strength and endurance test ing specific to the job tasks is helpful. Work hardening activities (repetitive movements that require strength and muscular endurance similar to the actual job tasks) performed during rehabilitation are beneficial for selected patients. For patients with ischemic ST-segment depression during exercise test ing or other higher risk patients, Holter monitoring with ST-segment sensitive equipment is helpful in determining the appropriateness of specific job tasks. For patients whose jobs require considerable lifting and carrying, strengthening activities during phase rehabilitation are emphasized. Other important factors such as environmental conditions (heat, cold, humidity, and air quality), psychologic stressors, duration of work periods, and job retraining should be analyzed. Many patients are able to return to work within 4 to 8 weeks after myocardial infarction.*^

Phase of rehabilitation continues for at least 9 months beyond phase . At our institution, the exercise portion of the program either is medically supervised at a community exercise facility (YMCA) or is purely an individual program at home or at an exercise facility. Participation in patient support groups such as the Coronary Club is encouraged. Program objectives are a further increase in exercise capacity, a return to appropriate job and recreational activities, and continued education and implementation of steps for modification of risk factors. In our program, patients return to the rehabilitation center for formal evaluations at 3 ,6 , and 9 months after completion of phase II. These evaluations include, as needed, exercise testing and refinement of the exercise prescription, determination of the status of risk factors (blood lipids, body composition, cessation of smoking, blood pressure, and management of stress), progress toward goals in rehabilitation, diet, medications, and previously unsolved problems. Further evaluations are scheduled as needed. Follow-up consultations enhance patient com-


pliance with life-style changes and in our view are a crucial factor for successful rehabilitation.

As with all longitudinal types of treatment, compliance with recommendations for rehabilitation is of concern. Modifications in life-style are not easily accomplished by most patients. Although potential dropouts cannot be accurately predicted, the following factors seem to increase the chance of general noncompliance: continued cigarette smoking, depressed mood, blue-collar occupations, poor left ventricular function, and obesity.**'

Phase IV of rehabilitation is the maintenance program (consisting of efforts to modify risk factors and a routine program of physical activity) that patients should continue indefinitely. Yearly evaluations including graded exercise test ing are recommended for most patients. Selected patients may require more frequent assessment .

R I S K S T R A T I F I C A T I O N A F T E R C A R D I A C E V E N T S After myocardial infarction or coronary artery bypass grafting procedures, patients may be categorized as either low or high risk for reinfarction and sudden death. High-risk patients are identified on the basis of left ventricular dysfunction (left ventricular ejection fraction of 40% or less), congestive heart failure, complex arrhythmia (particularly with late potentials on signal-averaged electrocardiography), and either obvious or silent ischemia.***" Exercise test ing soon after both myocardial infarction and coronary artery bypass grafting provides important prognostic information such as the angina threshold, ST-segment changes, exercise capacity, and presence of arrhythmia and forms the basis for the early rehabilitation exercise prescription. The exercise test may be a standard treadmill evaluation or may include nuclear imaging (radionuclide angiography or tomographic thall ium perfusion). Nuclear exercise tests , although more expensive than standard treadmill tests , seem superior to standard treadmill test ing for the purpose of risk stratification.** The exercise test may be performed either before dismissal of the patient from the

hospital or early in the outpatient phase of recovery. Generally, this early exercise evaluation has a low to moderate intensity endpoint of 5 to 6 mets or a heart rate of 120 to 130 beats/ min. At 6 to 8 weeks after the cardiac event, myocardial and sternal healing is generally complete. At this t ime, a second graded exercise test is recommended. Test endpoints include fatigue or adverse s igns or symptoms. The test may be a standard treadmill or nuclear study and may include expired gas analysis for precise determination of aerobic capacity.

A medically supervised outpatient rehabilitation program has distinct advantages, including close surveillance of patients, expert assistance in progressing the level of the activity program, availability of patient education services, and social support to facilitate patient adherence to the prescribed regimen. Many patients, however, do not have or do not take the opportunity to enroll in supervised rehabilitation programs because of financial or other concerns.'^" Home activity programs are feasible and beneficial for many low-risk cardiac patients. Investigators from Stanford pioneered the concept of risk stratification after myocardial infarction with medically directed home exercise training for low-risk p a t i e n t s . ' ' ' P a t i e n t surveillance during home exercise was accomplished by transtele-phonic electrocardiographic transmission. For the past 9 years, we have used home exercise training in conjunction with periodic visits to the rehabilitation center for some of our patients, and the results have been favorable.' For pat ients referred to a rehabilitation center, a home exercise component is critical for minimizing the potential patient-perceived dependence on supervision of all physical activity.

Because of the unsolved problem of early repeat occlusion, patients who have had a myocardial infarction and who have received thrombolytic agents or undergone percutaneous transluminal coronary angioplasty (or both) are best served by a medically supervised exercise program for 4 to 8 weeks after dismissal from the hospital. In our opinion, low-risk patients may safely participate exclusively in home exercise training if a medically supervised program is unavailable


or impractical. High-risk patients who cannot undergo revascularization or whose risk status cannot otherwise be improved are best served by a medically supervised exercise program and close surveillance. For all cardiac patients, participation in at least a brief supervised outpatient exercise program is indicated before exclusive use of a home activity regimen.

Many patients with severe left ventricular dysfunction are not referred for cardiac rehabilitation. Some cardiac rehabilitation programs have excluded these patients on the basis of concerns that they may not benefit from exercise training, that the long-term prognosis is dismal, and that exercise training may worsen left ventricular function and precipitate left ventricular failure or dangerous arrhythmias (or both). We^ -^ recently reviewed the outcome of participation in our outpatient cardiac rehabilitation program by 20 consecutive patients who had had a myocardial infarction and had resting left ventricular ejection fractions of less than 25% (mean, 21%). These patients had no contraindications to exercise test ing and training. N o serious complications of exercise training occurred during the 8-week supervised program, and a substantial training effect (38% increase in exercise capacity) was noted. Almost 60% of these pat ients returned to gainful employment, and most patients continued to exercise independently after graduating from the supervised program. We were encouraged by the relatively low annualized mortality rate of 8% over 3 years of follow-up. Thus, these patients should not be categorically denied the psychosocial and physical benefits of exercise training. Other investigators have also reported favorable results of rehabilitation with similar selected patients.^*'^*^ Recently, Sul l ivan and colleagues^ performed central and peripheral hemodynamic as well as metabolic measurements before and after a 4- to 6-month supervised exercise training program in 16 patients with a mean left ventricular ejection fraction of 24%. Maximal oxygen uptake increased a mean of 26% as a result of a widening of the arterial-mixed venous oxygen difference. After training, blood flow in the legs was significantly higher during maximal exercise. For

maximal exercise, cardiac output, left ventricular ejection fraction, and pulmonary capillary wedge pressure were unaltered by exercise training. No relationship was found between the observed training effect and baseline hemodynamic or metabolic variables.

R I S K S O F E X E R C I S E T R A I N I N G Exercise training in patients with coronary artery disease is not without risk. Contraindications to exercise test ing and training (Table 2) must be strictly followed. Advanced age and poor left ventricular function are not contraindications. Because cardiac patients may have a limited coronary reserve, the increase in myocardial oxygen demand during exercise may result in ischemia and may potentially precipitate a lethal arrhythmia or myocardial infarction. Cardiac arrest may occur long after the clinical event. With proper patient screening and care in prescribing exercise, exercise training can be safely performed by most cardiac patients. Reported complication rates for cardiac exercise sess ions are low. Van Camp and Peterson^' reported a rate for cardiac arrest of 1 in 111,996 hours of patient exercise and rates for myocardial infarction and sudden cardiac death of 1 in 293,990 and 1 in 783,972 hours of patient exercise, respectively. Typically, patients in whom life-threatening arrhythmia or myocardial infarction develops during exercise training demonstrate exercise-induced ischemia, have severe nonaltered coronary disease, and choose to exceed their prescribed upper limit heart rate during exercise sessions.^* All personnel involved in exercise programs and family members of cardiac patients, when appropriate, should undergo training in cardiopulmonary resuscitation in order to minimize the risk of an untoward event.

A recent report by Jugdutt and colleagues'^" urged caution in recommending exercise training for patients with moderate-sized anterior transmural myocardial infarctions who exhibited left ventricular asynergy (akinesia or dyskinesia) of 18% or more. After a 3-month moderate exercise program that began 15 weeks after infarction, these patients demonstrated more


cardiac shape distortion, expansion, and wall thinning. Left ventricular ejection fraction and functional capacity also worsened. We and others'* have not observed such deterioration in patients with large anterior infarcts, and further investigation is indicated before such patients are excluded from exercise training.

The importance of a supervised program of cardiac rehabilitation in detecting medical problems in participants was addressed by Sennett and associates." Of 365 patients who participated in a 12-week outpatient program, approximately 20% were referred to their primary physician for problems ascertained during rehabilitation sessions.

Musculoskeletal injuries are common in persons who participate in exercise programs. In general, higher intensity activities that involve weight bearing, such as jogging, traditional aerobic dancing, racket sports, and basketball, are more likely to result in injury than low-intensity activity. An assessment of previous injuries and orthopedic l imitations by a phys-iatrist and physical therapist is an important consideration. Prompt treatment and rehabilitation are of paramount importance in helping the patient resume an exercise schedule. Risks of injury can be minimized by using low-intensity activities such as walking or non-weight-bearing exercise such as stationary cycling, swimming, or other water activities.

E X E R C I S E P R E S C R I P T I O N An exercise prescription should be individualized and updated periodically for each patient and must include the following information: type (or types) of exercise, desired intensity, duration of exercise, frequency of exercise sessions, anticipated rate of progression of duration and frequency, specific warm-up and cool-down activities, and warning symptoms. Warning symptoms necessitating termination of exercise sess ions and consultation with a physician include (1) new onset or change in angina pectoris; (2) severe dyspnea; (3) unusual fatigue; (4) lightheadedness , syncope, or near-syncope; (5) musculoskeletal pain; (6) heart rate that exceeds the prescribed target rate; and (7) new onset of pulse

irregularity. Specific guidelines for exercise prescriptions for cardiac patients have been described elsewhere.''

Adaptations to exercise training are somewhat specific to the muscle groups involved in the exercise program. A portion of the exercise training session can be devoted to activities for the upper extremities such as arm ergometry, a combination of arm and leg ergometry (Schwinn Airdyne), hand dumbbell activities, or circuit weight training. Modest muscle-strengthening activities with use of weights or the patient's body weight are an important consideration for improving patient confidence and functional ability.

B E N E F I T S O F C A R D I A C R E H A B I L I T A T I O N Exercise training results in impressive benefits for most cardiac patients (Table 8). A reduction in the symptoms of angina pectoris, exercise-related dyspnea, fatigue, and claudication is an important outcome'"* (Fig. 2). The oxygen transport system adapts favorably to exercise training in most patients, as indicted by an improvement in maximal oxygen uptake (Vo^max) measured during incremental exercise testing. Patients who have exercise-induced ischemia during graded exercise testing often demonstrate less of an increase in Vo2max as a result of training than do other patients.'^ Vo^max may increase 10 to 30% or more in cardiac patients.'* Selected patients with poor left ventricular function may improve exercise capacity by an exercise training program.^ "'^ In general, the magnitude of the improvement in VOgmax is inversely proportional to the exercise capacity before training." The rate of improvement is greatest during the first 3 months of exercise training, but the increase in fitness continues for 6 months or longer.'" The increased physical work capacity results in use of a smaller proportion of the V O j m a x during routine activities (Fig. 3). As a result, tasks are performed with less fatigue, dyspnea, and perceived exertion, and the productivity and quality of life of the patient may be considerably enhanced. An increase in the arterial-mixed ve-


Table 8Benef i t s Derived From Long-Term Outpatient Cardiac Rehabi l i tat ion

Physiologic* Vo.^max i MVo.^ for given workload Muscle strength and endurance Blood fibrinolytic activity i Platelet aggregation i Catecholamines

Symptomatic I Angina pectoris i Dyspnea i Claudication i Fatigue

Anatomic i Progression of diseaset

Regression of diseaset

Psychologic i Anxiety and depression Confidence and self-esteem Knowledge

Epidemiologic i Morbidity i Mortality

Risk factors i Smoking i Total cholesterol and triglycerides High-density lipoprotein cholesterol i Obesity i Hypertension Carbohydrate metabolism

Economic Patient productivityt i Cases of disabilityt i Visits to physician's officet i Medications

*Vo.^max = maximal oxygen uptake; MVo,^ = myocardial oxygen demand. tPotential benefits.

nous oxygen difference (peripheral adaptation) as a result of an increase in blood volume, capillary density, and oxygen extraction from capillary blood by exercising skeletal muscle" and in cardiac output (central adaptation) accounts for the augmentat ion of VOgmax. An improvement in exercise stroke volume after 1 year of exercise training has been demonstrated in some, but not all, cardiac pat ients" '^ (Fig. 4). An increase in maximal heart rate has also been observed.'^ Improvement in submaximal exercise endurance and in muscular strength, independent of the improvement in Vo^max, has been substantiated and results in an improvement in physical work capacity. Increasing the muscular strength of the upper extremities results in use of a lower percentage of the maximal contractile force during routine tasks and enables patients to accomplish activities at a lower heart rate and blood pressure and thus at a lower myocardial oxygen demand.

For a specific exercise intensity, the myocardial oxygen requirement, as evidenced by a

reduction in the rate-pressure product, is reduced by approximately 18%" (Fig. 5). Furthermore, studies have provided evidence that myocardial perfusion is enhanced by exercise training in selected patients'** ''^ and that ST-segment depression and thall ium defects during exercise test ing are diminished' (Fig. 6). Investigators have found no evidence, however, that training improves the coronary collateral circulation in humans . Importantly, at a standard submaximal exercise intensity, free plasma catecholamine concentrations may be decreased by regular aerobic exercise ." In nonhuman primates, regular aerobic exercise training has been shown to reduce coronary atherosclerosis in the sett ing of diet-induced hypercholesterolemia and to result in increased epicardial coronary artery caliber.'*

In patients with coronary disease, moderate exercise training reduces platelet aggregation'" and probably increases fibrinolytic activity.*" Intense physical exercise with a large anaerobic metabolic component may result in a hyperco-


.1

Before training Alter training

Angina pectoris Anginai threshold

--io

Exercise intensity

Fig. 2. Effect of exercise training on exertional angina pectoris. (Modified from Franklin A, Rubenfire : Exercise training in coronary heart disease: mechanisms of improvement. Pract Cardiol 6:84-99, 1980. By permission of Med Publishing, Inc.)

agulable state.'^' Additional potential benefits of habitual physical activity include a reduced susceptibility to arrhythmia**' and increased resistance to ventricular fibrillation (data from studies in animals).**'

Cardiac patients who exercise regularly have an improved psychologic profilethat is, less anxiety and depression, more confidence, and more self-esteem than nonexercising patients.***"'^ Sanne** suggested that certain patient-perceived barriers to complete rehabilitation, such as fear of activity, fatigue, feeling of i l lness, emotional disturbance, angina pectoris, and a defeatist attitude, may be removed by exercise training. Potential economic benefits include an increase in patient occupational activity, a reduction in cases of disability, fewer visits to the physician's office, and a decrease in the requirement for medications. '

R I S K F A C T O R M O D I F I C A T I O N A N D S E C O N D A R Y P R E V E N T I O N The efficacy of modification of risk factors in reducing the progression of coronary artery disease and future morbidity and mortality has been established. Progression of disease in the native coronary vessels and in saphenous vein

bypass grafts has been linked to continued cigarette smoking, elevated total serum cholesterol and low levels of high-density lipoprotein cholesterol (HDL-C), hypertension, sedentary life-style, and elevated fasting blood glucose concentration.**'"" Drug therapy designed to minimize the occurrence of arrhythmias and ischemia, improve left ventricular function, alleviate symptoms, and improve platelet function provides important benefits for secondary prevention of cardiovascular disease. Such benefits have been reviewed in detail elsewhere."'

Control of Blood Lipids.Prospective trials have conclusively demonstrated the importance of lipid interventions directed at both low-density lipoprotein cholesterol (LDL-C) and the pivotal role of HDL-C in reducing cardiac events in patients with known coronary artery disease."' "* The Coronary Drug Project, a double-blind, randomized, placebo-controlled trial, was conducted in 8,241 male patients with a history of a prior myocardial infarction."'"' Despite only a 50% compliance with the drug regimen, pat ients treated with niacin had a 10% reduction in

Peak METS

75% 3 mph 60%

-

wdk

Before training

After training

Fig. 3. Effect of exercise training on peak oxygen uptake in metabolic energy equivalents (METS) and relative oxygen expenditure for walking 3 miles per hour (mph) on a level surface. After exercise training, peak oxygen uptake increased; thus, relative oxygen cost for the activity decreased. (From Franklin BA, Rubenfire M: Exercise training in coronary heart disease: mechanisms of improvement. Pract Cardiol 6:84-99,1980. By permission of Med Publishing, Inc.)


140

_ 120

2 So

100

80

60 h

40 J I I I L

Initial 12 months

_ l Rest .200 400 600. 35 50 65

Work rate, pmmin ' Work rate. % VO2 max

Fig. 4. Stroke volume at same absolute work rate (A) and same relative work rate (B) before () and after ( ))) 12 months of exercise training. Difference from before versus after training: *P


140

C

1

120

CC I

100

80

160

140

120

100

22

Initial 12 months

L I Stage I

L L Stage II Stage I Stage II Stage I

Treadmill test (Bruce protocol) stage I

Fig. 5. Effects of exercise training on heart rate (HR), systolic blood pressure (SBP), and rate-pressure product (RPP) at stages I and II of Bruce treadmill protocol. All variables after 12 months of training () were significantly (P


had a myocardial infarction and have adequately controlled hypertension in comparison with patients who have uncontrolled or inadequately controlled arterial pressure. Great efforts should be made to control arterial pressure with agents that do not adversely affect other cardiac risk factors."^"*

Control of hypertension may alleviate symptoms of angina and congestive heart failure. The lack of association between blood pressure after an infarct and survival may be a result of a reduction in blood pressure attributable to left ventricular dysfunction.

Control of Obesity.Correction of obesity independently has not been demonstrated to lower morbidity and mortality in cardiac patients. The reduction of excess body fat, however, decreases symptoms of angina and fatigue and improves established risk factors such as blood lipids, hypertension, elevated blood glucose concentration, platelet abnormalities, left ventricular hypertrophy, and a sedentary existence."" Apparently, abdominal or central obesity, as defined as a waist-to-hip ratio of greater than 1.0 in men and 0.85 in women, is associated with more of a cardiovascular risk than hip and leg obesity."-^"*

Psychologic Factors.The coronary-prone behavior pattern (type Aa high level of ambi-t iousness, aggressiveness, hostility, competitiveness , and t ime urgency) was originally identified as an independent risk factor for first myocardial infarction in the Western Collaborative Group Study.""^ The role of type A characteristics for secondary prevention is controversial. Data from the Recurrent Coronary Prevention Project indicate that intensive counseling can alter type A behavior and result in a decrease in the rates of recurrent myocardial infarction and cardiac death."" In that study, 151 patients received no specific counseling, 270 were given cardiac counseling, and 592 received cardiac and type A behavior counseling. At 4.5 years, type A behavior was reduced in 35.2% of the patients given cardiac and type A counseling in comparison with 9.8% of patients given only cardiac counseling. The cardiac recurrence rate of 12.9% in the type A counseling group was significantly

X QC X X

Q . CD (0

1 Ic 0)

30

20

10

-0.1

-0.2

CO 0.3 -

Initial 12 months

I I II

Treadmill stage

Fig. 6. Rate-pressure product and extent of ischemic ST-segment depression at two submaximal levels of Bruce treadmill protocol before () and after ( ) )^) 12 months of exercise training. Difference from before versus after training: *P


randomized trial of traditional cardiac rehabilitation procedures, Roviaro and associates"'' reported an improved understanding of heart disease, improved compliance with treatment recommendations, more positive self-perceptions, decreased employment-related stress, more enjoyment of leisure t ime, and more physical and sexual activity. Taylor and colleagues,*'' in a randomized and controlled trial, found that exercise training resulted in significant improvement in all measures of depression and anxiety relative to the control group. Burgess and coworkers"" also used a randomized, controlled study to evaluate the effects of comprehensive cardiac rehabilitation services. At 3 months after initiation of the program, patients in the treatment group were less distressed psychologically and less dependent on family support than the control subjects. The potential benefits of relaxation therapy after myocardial infarction were assessed in a randomized, controlled study by van Dixhoorn and associates."" When compared with a group of patients who underwent exercise training only, the patients who underwent muscle relaxation therapy and exercise training had a lower recurrence rate of cardiac events (17% versus 37%; = 0.05) during a 2- to 3-year period.

Exercise Training.Epidemiologic studies have demonstrated a strong inverse relationship between habitual physical activity and morbidity and mortality from primary coronary artery d i s e a s e . ' " ' " Powell and colleagues"" who summarized 47 epidemiologic studies concerning physical activity and coronary disease published in English, reported a strong (relative risk, 1.9), consistent, inverse relationship between routine physical activity and the incidence of coronary artery disease.

The available evidence about the role of habitual physical activity for second or subsequent coronary events is less impressive. Paffenbarger and Hyde , '" in an elegant epidemiologic study of Harvard alumni, indexed habitual physical activity in 782 alumni with known coronary disease. During approximately a 12-year study period, the more active subjects had a coronary event rate that was 30% lower than the less

400 h -

300

200

100

>2,000 kcal/week


pooled data from the trials to evaluate the effects of exercise on major cardiac events."**2''"*^ The most recent report by O'Connor and associates*^ pooled data from 22 randomized trials involving 4,554 patients who underwent follow-up for 3 years. In comparison with control subjects, these patients had a total mortality, cardiovascular mortality, and fatal reinfarction rate that were significantly reduced by 20%, 22%, and 25%, respectively. The importance of these data is substantial . The 20 to 25% reduction in cardiac events after cardiac rehabilitation including exercise training is similar to that demonstrated with other, more expensive, therapies including revascularization strategies and other medical regimens (-adrenergic blockers, lipid agents , and antihypertensive treatments) . Thus, exercise training is indicated and most effective for patients after acute myocardial infarction.

S E C O N D A R Y P R E V E N T I O N T R I A L S Control of blood lipids, cessation of smoking, control of hypertension, and perhaps regular aerobic exercise, when evaluated individually, demonstrate significant reductions in recurrence rates and cardiac-related deaths after the appearance of coronary artery disease. Combining the control of these risk factors should logically enhance secondary prevention to a greater extent than management of a single factor in isolation. Nevertheless , randomized trials of multidimensional cardiac rehabilitation programs have failed to show conclusive reductions in subsequent morbidity and mortality.

Kallio and colleagues''^' provided evidence that a multifactorial rehabilitation program improves survival in patients who have had a myocardial infarction. They randomized 301 men and 74 women into either a rehabilitation program that included exercise training, dietary and smok-ing-cessation advice, and psychosocial counseling or a control group. Relative to the control group, the experimental subjects had an improvement in blood lipids, blood pressure, and habitual exercise. The 3-year cumulative mortality was 18.6% in the intervention group versus 29.4% in the control group (P = 0.02) (Fig. 8).

Fig. 8. Cumulative percentage of deaths from coronary heart disease in multifactorial risk intervention (/) and control (C) groups. Circles denote the monthly cumulative mortality. (From Kallio and a s s o c i a t e s . B y permission of The Lancet Ltd.)

The difference was primarily the result of a reduction in the incidence of sudden death in the intervention group (5.8% versus 14.4%; P


quent cardiac events were minimized. No formal cardiac rehabilitation program was recommended for low-risk patients. Less than 8 weeks of rehabilitation was recommended for moderate-risk patients, and 8 to 12 weeks of cardiac rehabilitation was suggested for those designated as high risk on the basis of traditional clinical factors. Wenger and A l p e r t , w r i t i n g about the position paper, pointed out that it was an incomplete review because it excluded data from studies that used meta-analysis,"*" which have demonstrated a 20 to 25% improvement in survival advantage for patients randomized to exercise training. They also suggested that low-risk patients are excellent candidates for reduction of multifactorial risk factors to maintain their low-risk status.

Risk reduction is a result of education, counseling, and exercise training. For behavioral changes, not only education but also practice of new skills, measurement of benefit, and reinforcement of progress are necessary. Cardiac rehabilitation programs can provide this critical component of continuing care. The position paper advises individualization in designing rehabilitation programs based on patient needs. We agree completely with this concept, as do Wenger and Alpert,'"" who refer to "patient-oriented" rehabilitation as the appropriate model. The American Association of Cardiovascular and Pulmonary Rehabilitation's current position paper on the exercise-training component of cardiac rehabilitation provides a more comprehensive approach than the other report.'"' This s tatement emphasizes that medically prescribed and supervised exercise as part of a comprehensive rehabilitation program is a well-accepted standard of care throughout the world after acute myocardial infarction or revascularization procedures. They recommend a minimum of 2 to 3 months and ideally 6 months of medically supervised exercise training, although continued telemetric electrocardiographic monitoring is unnecessary for low-risk patients.

F U T U R E C O N S I D E R A T I O N S The key challenge in cardiac rehabilitation is continued patient adherence to the recommen

dations for life-style change: cessation of smoking, diet and weight control, regular physical activity, and control of blood lipids. Further investigation is needed to identify optimal delivery systems for patient education and motivation. The role of the family and other support systems needs further clarification. The role of the physician as a health educator and motivator has been addressed.'"' Characteristics of dropouts from supervised cardiac exercise programs (blue-collar occupation, continued cigarette smoking, poor social support, obesity, depressed mood, and poor left ventricular function) have been identified.* *' Patients who will be noncompliant, however, cannot be accurately predicted. Behavioral techniques such as self-reporting (exercise, relaxation, and diet logs), patient contracts, follow-up office visits specifically for cardiac rehabilitation purposes, and training for prevention of relapse are currently under study.'""

The data suggest that aggressive control of blood lipids in middle-aged male cardiac pat ients results in a reduction of both progression of disease and occurrence of cardiac events."^" Observations including women and elderly pat ients are lacking. Goals for blood lipids (total cholesterol 180 mg/dl or less, LDL-C 110 mg/dl or less, total cholesterol/HDL-C 3.5 or less, and triglycerides 120 mg/dl or less) in cardiac pat ients have been suggested'"* but have not yet been fully accepted by practitioners. Additional studies of control of blood lipids are needed.

The amount of exercise training necessary for the development of cardiovascular fitness has been well established.' Thus far, however, optimal amounts of physical activity for improvement of cardiovascular health and secondary prevention of cardiac disease have not been established. Recent data suggest that nonfor-mal exercise (such as routine walking, stair climbing, occupational activity, gardening, and home repairs) is helpful in reducing coronary risk. '"'"' Further investigation into the safety and efficacy of home exercise programs for cardiac patients is needed.

The assessment of job-related ability or disability for patients with cardiac disease is an


important aspect of cardiac rehabilitation. Unfortunately, after a cardiac event, many patients do not return to their previous occupation.*'*'^ For those with uncomplicated myocardial infarction whose jobs do not require heavy physical labor, recent evidence suggests that return to work as early as 1 month after myocardial infarction not only is possible but also provides patient-perceived psychologic benefits. *^ ^ For patients with physically demanding occupations, a work evaluation consisting of hemodynamic, electrocardiographic, and metabolic (VO2) responses to isometric, dynamic, and combination isometric and dynamic activity is helpful.^'*^' Assessment of disability should be studied further. Objective work-related data such as muscular strength and endurance and measured aerobic capacity are helpful. Medically supervised rehabilitation programs that emphasize work task simulation and training are needed.

More physicians, both subspecialists and primary-care practitioners, should receive training in cardiovascular rehabilitation and methods of secondary prevention of cardiovascular disease. Specific educational goals consist of exercise testing, exercise prescriptions, patient education, and techniques for modification of risk factors.

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