REVIEW ARTICLE
Sports Medicine 14 (4): 243-259, 1992 0112-1642/92/0010-0243/$08.50/0 © Adis International Limited. All rights reserved. SPOll77
Cardiac Rehabilitation Following Myocardial Infarction
A Practical Approach
lain C. Todd, Dzifa Wosornu, Isabella Stewart and Trevor Wild Department of Cardiology, The Victoria Infirmary, Glasgow, Scotland
Contents 243 245 245 246 246 248 248 249 251 251
252 253 255 255 255 255 256
Summary
Summary I. Cardiac Liaison Sister l.l The Need for Information 1.2 Who Should Provide the Information? 1.3 The Role of the Liaison Sister 2. Exercise Training 2.1 Assessment 2.2 Type of Exercise Programme 2.3 Benefits of Exercise Training 2.3.1 Peripheral Effects 2.3.2 Effects on Cardiovascular and Left Ventricular Function 2.3.3 Effects on Myocardial Perfusion 2.3.4 Secondary Prevention 2.3.5 Psychological Effects 2.3.6 Effects of Training on Risk Factors 2.4 Risks of Exercise Training 3. Conclusions
The concept of cardiac rehabilitation following myocardial infarction is not a new one but is now at last gaining acceptance as an essential part of the service to the coronary patient. Its aim is to restore the effectiveness of post-infarct patients by ensuring that they are well adjusted, well educated and fit and thereby best able to cope with the long term consequences of their ischaemic heart disease. The first essential factor for good rehabilitation is patient education. Studies have shown high levels of distress and anxiety after infarction and to a large extent this is related to lack of information. Where patients have been given adequate information concerning their condition and treatment there is a high level of patient satisfaction and greater compliance. It must be appreciated that stress and anxiety impair the patient's ability to assimilate information and therefore repeated reinforcement is necessary. During the in-hospital period, the staff who are caring for the patient are constantly changing and while there is a role for all to educate the patient, the use of a cardiac liaison sister provides a continuity throughout the early recovery period to ensure that the education process is adequate. The use of written material and both audio and video tapes is also helpful. It is also important for the liaison sister to extend her role to the patient's immediate family, who also require information, and finally the liaison sister can provide a link
244
Sports Medicine 14 (4) 1992
into the post discharge phase, to answer the many questions that arise at this time, and to provide encouragement to the patient who is attempting to modify his lifestyle by stopping smoking, changing his diet and taking regular exercise. The use of exercise training is the second vital ingredient for adequate rehabilitation. This begins in earnest after the 6-week assessment, which can provide information on which to base an exercise prescription. The majority of patients enrolled within exercise programmes are medically stable and relatively symptom-free. There is increasing evidence that those with extensive myocardial damage, left ventricular dysfunction or failure, and ongoing myocardial ischaemia may also benefit. Traditional training programmes have been hospital based and have used mainly aerobic exercise. However, home based programmes should not be discounted where they may be more economical, more convenient, and improve patient compliance. Similarly, circuit training with weights has been shown to improve aerobic endurance and muscle strength and to have additional benefits in improved treadmill time compared with traditional aerobic programmes. It is conceivable that strength training may gain acceptance in future programmes. While current guidelines suggest that 30 to 60 minutes of exercise training 2 to 3 times per week for 3 months is a reasonable approach, benefits may be gained from other regimens including much shorter periods of daily exercise. Tradition has again dictated the use of heart rate monitoring and target heart rates during exercise training but there is a growing use of simpler methods such as perceived exertion scales, where the patient's own maximum perceived level of exertion has been found to correlate well with 85% of maximum treadmill heart rate. The clear benefits of exercise training relate to its peripheral effects, which lead to reduction in heart rate and systolic blood pressure during exercise, reducing myocardial oxygen demand. This effect is muscle specific. The central effects of exercise training are still the subject of debate. While animal studies suggest improved cardiac performance and increases in coronary artery, capillary, and collateral vessel size, studies in humans are less clear. In normal individuals, and in some studies in cardiac patients, left ventricular dilatation and left ventricular hypertrophy have been shown to result from prolonged exercise training. These changes do not appear to be associated with improved ejection fraction, either at rest or during stress. Likewise, the majority of studies on myocardial perfusion suggest that this is not improved in most coronary patients, although it may be enhanced in those patients with evidence of continuing myocardial ischaemia, particularly where this is associated with angina pectoris. Such improvements may require training at a higher intensity than used in most programmes and for a longer duration. Meta-analysis of exercise rehabilitation programmes suggests that they produce a 20% reduction in mortality over a 3-year post infarct period. While there is little to suggest that exercise training produced psychological benefits in the long term, it has been shown to reduce hypertension and to improve lipoprotein profiles. The serious risks of exercise training are small. However, one has to accept that there is a transient increase in the risk of cardiac arrest during exercise, although habitual exercise is associated with an overall reduction in risk of cardiac arrest. The proven benefits of cardiac rehabilitation are such that all hospitals practising coronary care should aim to provide the minimum of a cardiac liaison sister to improve patient education and a simple exercise regimen to aid recovery.
The management of myocardial infarction has undergone dramatic change over the past 30 years since the inception of coronary care units. Patients are surrounded by an ever more bewildering array of electronic gadgetry designed to monitor every conceivable aspect of their cardiovascular response. They are injected by increasing numbers of drugs with impressive titles like '(j-blockers', 'inotropes', 'vasodilators' and 'thrombolytics'. After
the infarct they are 'processed' by early exercise testing, late exercise testing, coronary angiography, angioplasty and coronary grafting. Struggling over the years for recognition amongst its more glamorous counterparts has been the concept of cardiac rehabilitation. Like a tortoise amongst the hares it has made slow but steady progress without ever being 'fashionable'. Yet more and more institutions are adding rehabilitation programmes to the
245
Cardiac Rehabilitation
routine management of their coronary patients and in time hospitals which do not offer such a service may be seen to be failing to provide optimum care. How do we define cardiac rehabilitation? The Oxford Dictionary defines rehabilitation as 'restoration to privileges, reputation, or proper conditioning or to effectiveness by training'. This implies loss of privileges, reputation, conditioning and effectiveness and is as good as any description of the consequences of myocardial infarction. Confined to bed and harnessed by monitors the cardiac patient is as stripped of the privileges of normal living as one can be and although many of the more basic lifestyle functions are rapidly restored, like getting out of bed, washing and toileting oneself, there are limitations placed on activities even after discharge from hospital which signal that this is somehow a lesser person than before. Therefore, it must be one of the main aims of rehabilitation to restore the confidence not only of the patient in his own capabilities but also of those around the patient in order that his reputation and standing within the family and community may as far as possible be restored. The infarct patient will be out of condition as a result of his illness, the associated bed rest, and in many cases years of neglect. Clearly restoration of condition, therefore, is also a keystone of cardiac rehabilitation. Some patients may have suffered extensive myocardial damage and not have the potential to regain their former condition but the majority can achieve a fitness which they did not possess before their infarct. A holistic approach to cardiac rehabilitation, therefore, does indeed aim to restore the effectiveness of the post infarct patient by producing a well adjusted, well educated, fit individual who is able to cope with the health problems of his ischaemic heart disease. Cardiac rehabilitation does not stand as an alternative to good coronary care and appropriate medical treatment but rather it must dovetail in with the rest of the patient's management. As part of the whole process it is incumbent on the physician to address the underlying disease and to treat those individuals who have ongoing health problems. Such medical treatment will not only facilitate the further rehabilitation of the infarct patient
but also be facilitated by rehabilitation up to that time. This article reviews the evidence that these aims can be achieved by rehabilitation programmes and in particular considers the role of the rehabilitation or cardiac liaison sister and of the exercise training programme.
1. Cardiac Liaison Sister 1.1 The Need for Information
Myocardial infarction is for the sufferer and for his immediate family a major life event and one which may easily lead to psychological as well as physical disability. In an early study by Wynn, 400 patients were assessed (Wynn 1967). 50% suffered from emotional distress and 'invalidism' characterised by mild to severe anxiety states. A third felt they had received inadequate explanation regarding their illness and inadequate reassurance about their progress. More recently, Schuckit (1983) reported that 70% of patients in a study left coronary care units on medication for stress. 60% reported sleep disturbance after discharge and 60% reported anxiety leading to family disruption. 95% of spouses reported anxiety and 40% of all patients could be classed as psychologically impaired. He stressed the need for 'psychotherapy' in the form of education and reassurance to encourage the patient to participate in their own rehabilitation. Conroy and Mulcahy (1989) examined the evidence for genuine organic anxiety or depressive disorders in the post myocardial infarction patient. They concluded that the patient's emotional response was a normal and appropriate reaction to their illness which could be treated by appropriate psychological support. It would appear, therefore, that there may be a positive benefit in providing the patient with information about his condition and treatment. In Cartwright's study in 1964, 60% of patients reported difficulty in obtaining information while in hospital (Cartwright 1964); 40% said they asked for information more than it was volunteered. The main stumbling block was diffidence or fear of rebuttal of the patient. The use of technical terms inhibited patients as did the fear that their vocab-
246
ulary was inferior to that of their doctor. Social class was also important. In general, the higher social classes tended to ask for information, while the lower social classes waited to be told. However, overall there was a positive correlation between information given and patient satisfaction. The informed patient is a happy patient! In a further study, Ley and Spelman (1967) concluded that there was a positive correlation between patient satisfaction with information received and subsequent compliance with treatment. The happy patient is a compliant patient! Despite this early realisation that providing information could have significant benefits in terms of the psychological rehabilitation of the patient, the results of subsequent and current studies show a continuing desire for information on the part of the patient and varying degrees of failure to meet that desire on the part of the medical staff. There are a number of possible reasons for this. First, the staffs perception of what the patient needs to know or has assimilated may be inadequate. Jenkins and colleagues (1984) assessed the value of an information session given by coronary care unit nurses based mainly on exercise, smoking and sex. While up to 91 % felt the sessions were valuable, 50% wanted more help in these areas and 40% wanted information on other topics such as therapy. Nearly 50% wanted family involved in the sessions. Secondly, the patient may not be able to retain information. Rahe et al. reported poor retention of information by patients despite enthusiasm by both staff and patients for an education programme (Rahe et al. 1975). They concluded that information should be written rather than verbal to allow reinforcement. Scalzi et al. (1980) and Budan (1983) recognised the role of stress and anxiety in the poor results of early patient education. Both conclude that stress/anxiety leads to poor attention and either avoidance of or inability to retrieve information. While Budan (1983) takes the negative view that early teaching is, therefore, doomed to failure, Scalzi (1980) suggests that repeated reinforcement of information helps to reduce stress and improve concentration. Finally, Thompson (1989) suggests that such support and education must continue after
Sports Medicine 14 (4) 1992
discharge as, in males at least, anxiety and depression peak at 6 weeks with the prospect of return to work, driving and sexual relations. 1.2 Who Should Provide the Information? There is a traditional view that nurses care for the sick and doctors advise. This would certainly appear to be the case in studies by Tilley et al. (1987) and by Karlik & Yarcheski (1987). Both found that patients expressed a preference for receiving advice and information from medical staff and appropriate paramedical specialists such as dieticians rather than nurses. Woody et al. (1984) and Jenkins et al. (1984), however, reported that on the whole patients did learn what nurses taught and that education was a justifiable nursing role. Perhaps a combination of both would allow sufficient reinforcement of information. There is, however, a risk of too much information which may be further compounded by the transfer of patients from staff in the coronary care unit to medical wards and associated loss of continuity of information. The above difficulties may be eased by having a dedicated rehabilitation nurse. Pozen et al. (1977) reported that the use of a 'nurse rehabilitator' improved return to work, lessened cigarette smoking and increased patient knowledge. Naismith et al. (1979) reported similar benefits from a full time 'nurse counsellor'. Similar titles have been applied by other authors to what has become the cardiac liaison sister. 1.3 The Role of the Liaison Sister
Patients with uncomplicated myocardial infarction spend an average of 7 days in hospital. During that time they may spend time both in coronary care and in a general medical ward. They will be exposed to a number of different doctors and nurses and in addition perhaps dietitians, physiotherapists and social workers. They will transfer from the relative security of the coronary care unit to the open ward. They will be bombarded with information which they must digest and finally will be
Cardiac Rehabilitation
discharged. They are expected to cope with these ever changing stimuli and somehow come to terms with the major event in their lives and begin the process of recovery. The role of the liaison sister is to provide continuity throughout this period, thereby, to be seen by patients as someone from whom they can obtain information and with whom they can discuss their concerns. Rehabilitation starts when the patient is well enough to make simple decisions, the length of each formal session depending on the response from the individual. The general aim within the initial period is to offer patients and their relatives support and guidance to help them to take a more active role in their recovery. Early sessions involve education of the disease process and the healing mechanism, in addition to helping the patients and relatives to identify specific health risks in their lifestyles. Without such basic knowledge and understanding it is difficult for patients to make informed decisions about changes which need to be made and compliance with such changes would also diminish. The use of simple language allows patients to feel that they can communicate with the liaison sister and gives the patients the confidence to explore and increase their knowledge. The use of written material allows them greater freedom to take in information at their own pace. A combination of booklets, tape cassettes and videos may be used to expand their education. Tapes containing relaxation exercises to be used while in hospital may also be useful. Patients who are well informed and understand why this has happened to them can begin to explore the options towards making modifications to their health risks. While the patients may feel their physical state improving each day, their emotional responses may be going through many phases including anger, denial, fear and even rejection of themselves and their families. Depending on these responses more counselling sessions may be required and may also involve the family, even long after discharge, until all involved can come to terms with their feelings. During these early days the liaison sister will have encouraged the patients and their relatives to express themselves more openly and the basic edu-
247
cation allows them to achieve this more confidently. The patient's and relatives' individual needs will have been assessed through the nursing process and an individual plan for information and psychological and social support will have been implemented and be ongoing through the patient's stay in hospital and after discharge. The phase of mobilisation begins with the transfer of the patient from the monitored room. This is a stressful time for many patients who fear the loss of the monitored situation and the security which it gave. They need increased reassurance with regard to their increasing mobility and independence. Since at this time they may be in a new environment with unfamiliar medical and nursing staff the continued contact with the liaison sister provides a continuity of care both for the patient and for the staff. The new staff can be informed of patients' fears, their stage of education and social factors which need attending to. The knowledge that this information has been successfully communicated to the new staff is reassuring both to the patient and relatives. It is at this stage that patients begin to take a more active role in their rehabilitation as they begin preparing for home. Discussions at this time relate to mobility and exercise, as well as hobbies and the return to normal life. Patients need time to discuss the merits of returning to work or taking retirement and since many may not yet have the confidence to explore their options it can be helpful for the liaison sister to assist the patient in making appropriate decisions. Information is given on such matters as driving, flying and alcohol consumption. Drugs which have been given to the patient and those which he may receive on discharge are explained with information as to how they should be used at home and the possible side effects. By the end of the 7 days in hospital, patients and their relatives should be developing a positive attitude towards recovery and an increased awareness of their ability to return to a normal lifestyle. The last session before discharge will involve reinforcement of all the previous information and further details on how to reduce risk factors in their lifestyle after discharge. Information on possible
248
mood changes and the physical symptoms which may occur during the recovery period at home is given with advice on how to deal with those problems which occur. Both patients and their partners are understandably worried about returning to a normal sex life and this is discussed before discharge with both to help to alleviate the anxiety which may occur at a later date. After discharge there is a contact telephone service which allows the patients and relatives to phone the liaison sister to discuss problems or worries which they are experiencing during the early post discharge recovery period. Patients are encouraged to use this service, but in addition specific arrangements should be made for contact between the liaison sister and the patient at the end of the first 7 days at home, preferably by means of a home visit. Ideally, such support continues throughout the following weeks, taking the patients through to their review in the outpatient clinic 6 weeks after their infarct when enrolment in the formal exercise programme or further investigation may be considered. Such a post has been shown to produce positive results in our institution. Like Pozen (1977) and Naismith et al. (1979) we have found a 50% return to work at 8 weeks after admission to a coronary care unit with a myocardial infarction (MI) compared with 26% before the appointment of a liaison sister. Overall patient satisfaction with information increased significantly after the liaison sister began. This was particularly notable among those admitted with an episode of cardiac pain which did not lead to myocardial infarction such as unstable angina. 77% of patients reported lack of information pre liaison sister, compared to 33% in the first 3 months after the appointment. Interestingly, the teaching given by the liaison sister also led to improved patient satisfaction with advice from other nurses and medical staff. This was perhaps because of improved understanding by the patient, the key to effective rehabilitation (unpublished data).
2. Exercise Training 2.1 Assessment Assessment for exercise training generally takes place at the 6 week review appointment. By this stage the patient who is progressing well will have
Sports Medicine 14 (4) 1992
been encouraged to walk each day up to 2 miles and, with the exception of returning to work, may have been restored to all other routine activities. It is also to be hoped that they have already significantly modified their lifestyle in terms of smoking habits, exercise and diet. Some patients will not have progressed so well and the physician may identify clinical reasons for this in terms of angina pectoris, cardiac failure or poor left ventricular function. Such assessment may be aided by carrying out an ECG and chest x-ray and by the performance of the now almost obligatory exercise tolerance test. This will identify a group of patients who require further assessment by coronary angiography with a view to revascularisation. Unless there is a delay in angiography such patients are normally not enrolled in the exercise programme at this stage, though they may of course enter it either while awaiting surgery or as postcoronary artery bypass graft patients. The exercise tolerance test may also be used to identify patients with ventricular arrhythmias induced by exercise as such patients are normally excluded from training, though it must be realised that exercise testing does not always identify those at risk of serious arrhythmias on exercise as such arrhythmias can be unpredictable in timing and provocation. However, for the majority, exercise tolerance tests provide reassurance before commencing training. Most patients are surprised that they can do so well and indeed that they are allowed to exercise in such a vigorous way. It provides both a stimulus to begin training and a benchmark against which they may assess their subsequent improvements. The physician on the other hand can categorise his patients in terms of fitness on the treadmill, presence of chest pain or ST depression and dyspnoea. While we may not have achieved sufficient sophistication to be able to prescribe an ideal programme for each type of problem, we can use this clinical information as a guide to how far and how fast to push that patient and what degree of supervision to give him. Most programmes, for example, base exercise prescription on the patient's symptom limited heart rate and this can be readily measured.
Cardiac Rehabilitation
It is usually the stable, relatively symptom free patient who is admitted to the exercise programme but extensive myocardial damage does not preclude the development of a training response and its benefits. As with normal sedentary persons it is the patient most out of condition who has most to gain from exercise and patient motivation is the vital component for success. In 1 study, patients who defaulted from an exercise programme had a reinfarction rate of approximately 50% while those who continued to exercise had a 2% recurrence rate over 3 years (Kavanagh et al. 1979).
249
erate load with frequent repetitions. Circuit training has been shown to be safe and to result in a significant increase in aerobic endurance and muscular strength (Ghilarducci et al. 1989) with in-
Table I. Victoria Infirmary power exercise training programme
Power exercises Bench press
Military press
2.2 Type of Exercise Programme After discharge, patients are advised to take short daily walks as a prelude to formal exercise training. The exercise training programme should be user friendly and encourage compliance. The sessions should start with a warm-up period and end with a cool down period (Naughton 1977). Training programmes have traditionally been aerobic exercise based, largely because this form of exercise has been extensively studied in normals and in patients with heart disease. Aerobic exercise is recommended for cardiac patients. It involves rhythmic movement of large muscle groups associated with increased cardiac output, ventilation and oxygen consumption. Strength training has been less popular and has been considered dangerous for cardiac patients because of its association with isometric exercise. The latter type of exercise causes a pressure rather than a volume load and therefore does not cause a sustained increase in cardiac output. Strength training, however, is not totally isometric as there is development of muscle tension against resistance plus movement of muscle groups with increased blood flow and cardiac output. It results in increased muscle mass, strength and cardiac size (Sparling et al. 1990). Strength training, however, has not been extensively studied in cardiac patients. Circuit training which does involve training with weights is gradually being included in rehabilitation programmes (Ghilarducci et al. 1989; Keleman et al. 1986). It involves lifting weights of mod-
Biceps curl
Upright row
Pull down
Push down
Pulley row
Quadriceps curl
Hamstrings curl
Situps
Lie on back on bench. feet on floor. equipment behind head. Raise weight by pulling bar down towards head'. Return to starting position Kneel facing equipment. Raise weight by pushing angled bar from chest level above head. fully extending arms. Return to starting position Stand facing equipment. Bend forearms to 90°. palms upwards. elbows tucked into sides. Raise weight by pulling bar uP. till arms are fully flexed. Return to starting position Stand facing equipment. Arms extended. palms downward. pull bar up towards chin. abduct upper arms so elbows move outwards. Return to starting position Sit on stool with equipment behind body. Raise weight by pulling bar down behind head. Return to starting position Stand facing equipment. Bend arms to 90° palms downwards. Raise weight by pushing bar down till arms fully extended. Return to starting position Sit on mat. legs fully extended. facing equipment. Reach for bar. Raise weight by pulling bar towards body. Return to starting position Sit on edge of bench with cushioned bar at feet equipment behind body. Flex ankle to hold bar. Raise weight by extending knees. Return to starting position Lie prone on bench. cushioned bar at feet. facing eqUipment. Rest bar on posterior aspect of ankle (Achilles tendon). Raise weight by flexing at knees while holding onto side of bench with hands to stabilise upper body. Return to starting position Lie supine on mat. legs fully extended. Grip fixed cushioned bar with feet. ankles flexed. Raise upper body. try to touch knees with forehead. Return to starting position
250
creases in treadmill time in patients so trained compared with controls who continued a traditional aerobic programme (Keleman et al. 1986). Circuit weight training has been shown to be safe with regard to blood pressure response and beneficial in terms of muscle strength. We have incorporated circuit weight training in the Victoria Infirmary rehabilitation programme with no exercise related cardiac events (unpublished data). The duration, frequency and intensity of exercise training need to be considered. The duration of training in reported studies has varied from 4 weeks to several years. The optimal duration is not yet determined but a training effect can be achieved after 4 weeks' intensive aerobic exercise training (Nordrelaug et al. 1989). Most would agree that 30 to 60 minutes of exercise 2 to 3 times per week for 3 months is adequate for a training effect (Naughton 1977). Heart rate monitoring is optional but may become an obsession with some well intentioned patients. Patients should be encouraged to exercise to their own maximum perceived level of exertion by the end of their training period. This has been found to correlate well with 85% of maximum heart rate achieved on exercise testing. Patients should be started off at low levels of exercise, increasing as appropriate according to symptoms and performance to a maximum level. Most exercise training programmes are supervised on site by doctor/nurse and physiotherapist. Home based programmes have also been assessed, and while some have found them to be beneficial (Bethell et al. 1990), others have not (Palatsi 1976). They are certainly more economically viable than fully equipped gymnasiums. Patients with negative exercise tests after myocardial infarction are perhaps well suited to unsupervised exercise training. The Victoria Infirmary exercise training programme is shown in tables I and II. A wide range of aerobic exercises can be undertaken by cardiac patients. The programme we currently use is modified from the Canadian Air Force Training Programme (Royal Canadian Air Force 1973). Each patient is started off at the lowest level and advances through the levels at a rate
Sports Medicine 14 (4) 1992
Table II. Victoria Infirmary aerobic exercise training programme Aerobic exercises Arm circling Stand with feet slightly apart. Abduct arms and rotate first forwards and then backwards Stand facing step 6-10in (150-250mm) Stepups high. Step up and down at moderate pace, alternating left and right legs Trunk rotation Stand with feet slightly apart, hands on hips. Rotate trunk to right and left alternately Star jumps Stand with feet together. Jump up, abducting legs and arms fully. Return to starting position Crook lying Lie on back, arms at sides. Knees flexed. trunk rotation Rotate lower trunk from side to side Side lying hip Lie on right side, right arm stretched abduction above head, left arm supporting upper body at chest level. Right knee flexed. Abduct left leg to 90·. Return to starting position. Repeat on left side Stand with feet together, arms at sides. Standing trunk Bend at knees to lower body towards curls mat with arms stretched forwards. Return to starting position Crook lying Lie on back, knees flexed. Raise lower bridging trunk while keeping feet and shoulders on mat. Return to starting position Arm raising Stand with feet together, arms at sides, raise arms up above head. Return to starting position Trunk side Stand with feet slightly apart, arms at flexion sides. Flex trunk to right, sliding hand down right leg. Return to starting position. Repeat on left side Running on Raise feet at least 4 to 6in (100-150mm) the spot off mat, running on the spot for 1 minute
depending primarily on the symptoms. The number of repetitions of each exercise is increased over the period of training. On completing the circuit the patient finishes off the session on an exercise bicycle. Each patient's progress in the exercise class is continually assessed by a physiotherapist and rehabilitation nurse and he or she is advised about appropriate rate of progress depending on his or her performance and symptoms. Motivation is obviously paramount in such a setting - some take on more than they should, while others fail to tackle what they should be able to manage. At the end
Cardiac Rehabilitation
251
of the training period each patient should be exercising to his or her own perceived maximum level of exertion, irrespective of the form of exercise training undertaken.
Use of these muscles leads to a reflex rise in heart rate. The more work the muscle has to do, the greater the rise in heart rate. Trained muscle will respond with a smaller incremental rise, thus leading to a lesser degree of cardiac work for a given degree of peripheral work. If cardiac work is the limiting factor in patients with heart disease, then a higher degree of peripheral work may be achieved before that ceiling is reached. It is clear that the training effect is muscle specific, for example, training the leg muscles only will have no effect on the heart rate response to arm exercise (Clausen et al. 1973). Furthermore, early work suggested that a minimum duration and frequency of exercise was necessary to achieve a training effect (Pollock 1973; Pollock et al. 1972). This established the accepted guidelines for exercise training (American College of Sports Medicine 1975; American Heart Association 1972). The norm for programmes has been 3 sessions per week of 35 minutes minimum duration at 70% of maximum heart rate. The training effect may be established by periods of training as short as 4 weeks.
2.3 Benefits of Exercise Training 2.3. J Peripheral Effects The relative contributions of peripheral and central mechanisms in the training response continues to be the subject of much debate. However, the common factors in all exercise programmes leading to improved exercise tolerance are a reduction in resting heart rate and a reduction in both heart rate and systolic blood pressure at given levels of exercise after training (Clausen et al. 1969). This leads to a reduction in myocardial oxygen demand. This 'training effect' is of peripheral rather than cardiac origin. Figure 1 shows the control mechanisms responsible for such changes. The cardiovascular control area in the midbrain modulates heart rate via vagal and sympathetic efferents. Among the afferents to this control area are fibres originating in stretch receptors and skeletal muscle.
Cardiovascular control area
/
_,-+:,,@MusClekidneyandsPlanchnicarteriOles . -
>-----+'url:
_______
,
____:___
~A~ ~
.------,
I
:,--< +
~
,
0
Splanchnic capacitance vessels
; 8
l--:.: @ Cutaneous veins : J"\ L~~ Adrenalone (eplnephnne) Adrenal
!---J. 2
l
l---------+:.r~A A
:
L------L-!.At L--------~cl
Fig. 1. Neurological cardiovascular control mechanisms.
Sports Medicine 14 (4): 243-259, 1992 0112-1642/92/0010-0243/$08.50/0 © Adis International Limited. All rights reserved. SPOll77
Cardiac Rehabilitation Following Myocardial Infarction
A Practical Approach
lain C. Todd, Dzifa Wosornu, Isabella Stewart and Trevor Wild Department of Cardiology, The Victoria Infirmary, Glasgow, Scotland
Contents 243 245 245 246 246 248 248 249 251 251
252 253 255 255 255 255 256
Summary
Summary I. Cardiac Liaison Sister l.l The Need for Information 1.2 Who Should Provide the Information? 1.3 The Role of the Liaison Sister 2. Exercise Training 2.1 Assessment 2.2 Type of Exercise Programme 2.3 Benefits of Exercise Training 2.3.1 Peripheral Effects 2.3.2 Effects on Cardiovascular and Left Ventricular Function 2.3.3 Effects on Myocardial Perfusion 2.3.4 Secondary Prevention 2.3.5 Psychological Effects 2.3.6 Effects of Training on Risk Factors 2.4 Risks of Exercise Training 3. Conclusions
The concept of cardiac rehabilitation following myocardial infarction is not a new one but is now at last gaining acceptance as an essential part of the service to the coronary patient. Its aim is to restore the effectiveness of post-infarct patients by ensuring that they are well adjusted, well educated and fit and thereby best able to cope with the long term consequences of their ischaemic heart disease. The first essential factor for good rehabilitation is patient education. Studies have shown high levels of distress and anxiety after infarction and to a large extent this is related to lack of information. Where patients have been given adequate information concerning their condition and treatment there is a high level of patient satisfaction and greater compliance. It must be appreciated that stress and anxiety impair the patient's ability to assimilate information and therefore repeated reinforcement is necessary. During the in-hospital period, the staff who are caring for the patient are constantly changing and while there is a role for all to educate the patient, the use of a cardiac liaison sister provides a continuity throughout the early recovery period to ensure that the education process is adequate. The use of written material and both audio and video tapes is also helpful. It is also important for the liaison sister to extend her role to the patient's immediate family, who also require information, and finally the liaison sister can provide a link
244
Sports Medicine 14 (4) 1992
into the post discharge phase, to answer the many questions that arise at this time, and to provide encouragement to the patient who is attempting to modify his lifestyle by stopping smoking, changing his diet and taking regular exercise. The use of exercise training is the second vital ingredient for adequate rehabilitation. This begins in earnest after the 6-week assessment, which can provide information on which to base an exercise prescription. The majority of patients enrolled within exercise programmes are medically stable and relatively symptom-free. There is increasing evidence that those with extensive myocardial damage, left ventricular dysfunction or failure, and ongoing myocardial ischaemia may also benefit. Traditional training programmes have been hospital based and have used mainly aerobic exercise. However, home based programmes should not be discounted where they may be more economical, more convenient, and improve patient compliance. Similarly, circuit training with weights has been shown to improve aerobic endurance and muscle strength and to have additional benefits in improved treadmill time compared with traditional aerobic programmes. It is conceivable that strength training may gain acceptance in future programmes. While current guidelines suggest that 30 to 60 minutes of exercise training 2 to 3 times per week for 3 months is a reasonable approach, benefits may be gained from other regimens including much shorter periods of daily exercise. Tradition has again dictated the use of heart rate monitoring and target heart rates during exercise training but there is a growing use of simpler methods such as perceived exertion scales, where the patient's own maximum perceived level of exertion has been found to correlate well with 85% of maximum treadmill heart rate. The clear benefits of exercise training relate to its peripheral effects, which lead to reduction in heart rate and systolic blood pressure during exercise, reducing myocardial oxygen demand. This effect is muscle specific. The central effects of exercise training are still the subject of debate. While animal studies suggest improved cardiac performance and increases in coronary artery, capillary, and collateral vessel size, studies in humans are less clear. In normal individuals, and in some studies in cardiac patients, left ventricular dilatation and left ventricular hypertrophy have been shown to result from prolonged exercise training. These changes do not appear to be associated with improved ejection fraction, either at rest or during stress. Likewise, the majority of studies on myocardial perfusion suggest that this is not improved in most coronary patients, although it may be enhanced in those patients with evidence of continuing myocardial ischaemia, particularly where this is associated with angina pectoris. Such improvements may require training at a higher intensity than used in most programmes and for a longer duration. Meta-analysis of exercise rehabilitation programmes suggests that they produce a 20% reduction in mortality over a 3-year post infarct period. While there is little to suggest that exercise training produced psychological benefits in the long term, it has been shown to reduce hypertension and to improve lipoprotein profiles. The serious risks of exercise training are small. However, one has to accept that there is a transient increase in the risk of cardiac arrest during exercise, although habitual exercise is associated with an overall reduction in risk of cardiac arrest. The proven benefits of cardiac rehabilitation are such that all hospitals practising coronary care should aim to provide the minimum of a cardiac liaison sister to improve patient education and a simple exercise regimen to aid recovery.
The management of myocardial infarction has undergone dramatic change over the past 30 years since the inception of coronary care units. Patients are surrounded by an ever more bewildering array of electronic gadgetry designed to monitor every conceivable aspect of their cardiovascular response. They are injected by increasing numbers of drugs with impressive titles like '(j-blockers', 'inotropes', 'vasodilators' and 'thrombolytics'. After
the infarct they are 'processed' by early exercise testing, late exercise testing, coronary angiography, angioplasty and coronary grafting. Struggling over the years for recognition amongst its more glamorous counterparts has been the concept of cardiac rehabilitation. Like a tortoise amongst the hares it has made slow but steady progress without ever being 'fashionable'. Yet more and more institutions are adding rehabilitation programmes to the
245
Cardiac Rehabilitation
routine management of their coronary patients and in time hospitals which do not offer such a service may be seen to be failing to provide optimum care. How do we define cardiac rehabilitation? The Oxford Dictionary defines rehabilitation as 'restoration to privileges, reputation, or proper conditioning or to effectiveness by training'. This implies loss of privileges, reputation, conditioning and effectiveness and is as good as any description of the consequences of myocardial infarction. Confined to bed and harnessed by monitors the cardiac patient is as stripped of the privileges of normal living as one can be and although many of the more basic lifestyle functions are rapidly restored, like getting out of bed, washing and toileting oneself, there are limitations placed on activities even after discharge from hospital which signal that this is somehow a lesser person than before. Therefore, it must be one of the main aims of rehabilitation to restore the confidence not only of the patient in his own capabilities but also of those around the patient in order that his reputation and standing within the family and community may as far as possible be restored. The infarct patient will be out of condition as a result of his illness, the associated bed rest, and in many cases years of neglect. Clearly restoration of condition, therefore, is also a keystone of cardiac rehabilitation. Some patients may have suffered extensive myocardial damage and not have the potential to regain their former condition but the majority can achieve a fitness which they did not possess before their infarct. A holistic approach to cardiac rehabilitation, therefore, does indeed aim to restore the effectiveness of the post infarct patient by producing a well adjusted, well educated, fit individual who is able to cope with the health problems of his ischaemic heart disease. Cardiac rehabilitation does not stand as an alternative to good coronary care and appropriate medical treatment but rather it must dovetail in with the rest of the patient's management. As part of the whole process it is incumbent on the physician to address the underlying disease and to treat those individuals who have ongoing health problems. Such medical treatment will not only facilitate the further rehabilitation of the infarct patient
but also be facilitated by rehabilitation up to that time. This article reviews the evidence that these aims can be achieved by rehabilitation programmes and in particular considers the role of the rehabilitation or cardiac liaison sister and of the exercise training programme.
1. Cardiac Liaison Sister 1.1 The Need for Information
Myocardial infarction is for the sufferer and for his immediate family a major life event and one which may easily lead to psychological as well as physical disability. In an early study by Wynn, 400 patients were assessed (Wynn 1967). 50% suffered from emotional distress and 'invalidism' characterised by mild to severe anxiety states. A third felt they had received inadequate explanation regarding their illness and inadequate reassurance about their progress. More recently, Schuckit (1983) reported that 70% of patients in a study left coronary care units on medication for stress. 60% reported sleep disturbance after discharge and 60% reported anxiety leading to family disruption. 95% of spouses reported anxiety and 40% of all patients could be classed as psychologically impaired. He stressed the need for 'psychotherapy' in the form of education and reassurance to encourage the patient to participate in their own rehabilitation. Conroy and Mulcahy (1989) examined the evidence for genuine organic anxiety or depressive disorders in the post myocardial infarction patient. They concluded that the patient's emotional response was a normal and appropriate reaction to their illness which could be treated by appropriate psychological support. It would appear, therefore, that there may be a positive benefit in providing the patient with information about his condition and treatment. In Cartwright's study in 1964, 60% of patients reported difficulty in obtaining information while in hospital (Cartwright 1964); 40% said they asked for information more than it was volunteered. The main stumbling block was diffidence or fear of rebuttal of the patient. The use of technical terms inhibited patients as did the fear that their vocab-
246
ulary was inferior to that of their doctor. Social class was also important. In general, the higher social classes tended to ask for information, while the lower social classes waited to be told. However, overall there was a positive correlation between information given and patient satisfaction. The informed patient is a happy patient! In a further study, Ley and Spelman (1967) concluded that there was a positive correlation between patient satisfaction with information received and subsequent compliance with treatment. The happy patient is a compliant patient! Despite this early realisation that providing information could have significant benefits in terms of the psychological rehabilitation of the patient, the results of subsequent and current studies show a continuing desire for information on the part of the patient and varying degrees of failure to meet that desire on the part of the medical staff. There are a number of possible reasons for this. First, the staffs perception of what the patient needs to know or has assimilated may be inadequate. Jenkins and colleagues (1984) assessed the value of an information session given by coronary care unit nurses based mainly on exercise, smoking and sex. While up to 91 % felt the sessions were valuable, 50% wanted more help in these areas and 40% wanted information on other topics such as therapy. Nearly 50% wanted family involved in the sessions. Secondly, the patient may not be able to retain information. Rahe et al. reported poor retention of information by patients despite enthusiasm by both staff and patients for an education programme (Rahe et al. 1975). They concluded that information should be written rather than verbal to allow reinforcement. Scalzi et al. (1980) and Budan (1983) recognised the role of stress and anxiety in the poor results of early patient education. Both conclude that stress/anxiety leads to poor attention and either avoidance of or inability to retrieve information. While Budan (1983) takes the negative view that early teaching is, therefore, doomed to failure, Scalzi (1980) suggests that repeated reinforcement of information helps to reduce stress and improve concentration. Finally, Thompson (1989) suggests that such support and education must continue after
Sports Medicine 14 (4) 1992
discharge as, in males at least, anxiety and depression peak at 6 weeks with the prospect of return to work, driving and sexual relations. 1.2 Who Should Provide the Information? There is a traditional view that nurses care for the sick and doctors advise. This would certainly appear to be the case in studies by Tilley et al. (1987) and by Karlik & Yarcheski (1987). Both found that patients expressed a preference for receiving advice and information from medical staff and appropriate paramedical specialists such as dieticians rather than nurses. Woody et al. (1984) and Jenkins et al. (1984), however, reported that on the whole patients did learn what nurses taught and that education was a justifiable nursing role. Perhaps a combination of both would allow sufficient reinforcement of information. There is, however, a risk of too much information which may be further compounded by the transfer of patients from staff in the coronary care unit to medical wards and associated loss of continuity of information. The above difficulties may be eased by having a dedicated rehabilitation nurse. Pozen et al. (1977) reported that the use of a 'nurse rehabilitator' improved return to work, lessened cigarette smoking and increased patient knowledge. Naismith et al. (1979) reported similar benefits from a full time 'nurse counsellor'. Similar titles have been applied by other authors to what has become the cardiac liaison sister. 1.3 The Role of the Liaison Sister
Patients with uncomplicated myocardial infarction spend an average of 7 days in hospital. During that time they may spend time both in coronary care and in a general medical ward. They will be exposed to a number of different doctors and nurses and in addition perhaps dietitians, physiotherapists and social workers. They will transfer from the relative security of the coronary care unit to the open ward. They will be bombarded with information which they must digest and finally will be
Cardiac Rehabilitation
discharged. They are expected to cope with these ever changing stimuli and somehow come to terms with the major event in their lives and begin the process of recovery. The role of the liaison sister is to provide continuity throughout this period, thereby, to be seen by patients as someone from whom they can obtain information and with whom they can discuss their concerns. Rehabilitation starts when the patient is well enough to make simple decisions, the length of each formal session depending on the response from the individual. The general aim within the initial period is to offer patients and their relatives support and guidance to help them to take a more active role in their recovery. Early sessions involve education of the disease process and the healing mechanism, in addition to helping the patients and relatives to identify specific health risks in their lifestyles. Without such basic knowledge and understanding it is difficult for patients to make informed decisions about changes which need to be made and compliance with such changes would also diminish. The use of simple language allows patients to feel that they can communicate with the liaison sister and gives the patients the confidence to explore and increase their knowledge. The use of written material allows them greater freedom to take in information at their own pace. A combination of booklets, tape cassettes and videos may be used to expand their education. Tapes containing relaxation exercises to be used while in hospital may also be useful. Patients who are well informed and understand why this has happened to them can begin to explore the options towards making modifications to their health risks. While the patients may feel their physical state improving each day, their emotional responses may be going through many phases including anger, denial, fear and even rejection of themselves and their families. Depending on these responses more counselling sessions may be required and may also involve the family, even long after discharge, until all involved can come to terms with their feelings. During these early days the liaison sister will have encouraged the patients and their relatives to express themselves more openly and the basic edu-
247
cation allows them to achieve this more confidently. The patient's and relatives' individual needs will have been assessed through the nursing process and an individual plan for information and psychological and social support will have been implemented and be ongoing through the patient's stay in hospital and after discharge. The phase of mobilisation begins with the transfer of the patient from the monitored room. This is a stressful time for many patients who fear the loss of the monitored situation and the security which it gave. They need increased reassurance with regard to their increasing mobility and independence. Since at this time they may be in a new environment with unfamiliar medical and nursing staff the continued contact with the liaison sister provides a continuity of care both for the patient and for the staff. The new staff can be informed of patients' fears, their stage of education and social factors which need attending to. The knowledge that this information has been successfully communicated to the new staff is reassuring both to the patient and relatives. It is at this stage that patients begin to take a more active role in their rehabilitation as they begin preparing for home. Discussions at this time relate to mobility and exercise, as well as hobbies and the return to normal life. Patients need time to discuss the merits of returning to work or taking retirement and since many may not yet have the confidence to explore their options it can be helpful for the liaison sister to assist the patient in making appropriate decisions. Information is given on such matters as driving, flying and alcohol consumption. Drugs which have been given to the patient and those which he may receive on discharge are explained with information as to how they should be used at home and the possible side effects. By the end of the 7 days in hospital, patients and their relatives should be developing a positive attitude towards recovery and an increased awareness of their ability to return to a normal lifestyle. The last session before discharge will involve reinforcement of all the previous information and further details on how to reduce risk factors in their lifestyle after discharge. Information on possible
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mood changes and the physical symptoms which may occur during the recovery period at home is given with advice on how to deal with those problems which occur. Both patients and their partners are understandably worried about returning to a normal sex life and this is discussed before discharge with both to help to alleviate the anxiety which may occur at a later date. After discharge there is a contact telephone service which allows the patients and relatives to phone the liaison sister to discuss problems or worries which they are experiencing during the early post discharge recovery period. Patients are encouraged to use this service, but in addition specific arrangements should be made for contact between the liaison sister and the patient at the end of the first 7 days at home, preferably by means of a home visit. Ideally, such support continues throughout the following weeks, taking the patients through to their review in the outpatient clinic 6 weeks after their infarct when enrolment in the formal exercise programme or further investigation may be considered. Such a post has been shown to produce positive results in our institution. Like Pozen (1977) and Naismith et al. (1979) we have found a 50% return to work at 8 weeks after admission to a coronary care unit with a myocardial infarction (MI) compared with 26% before the appointment of a liaison sister. Overall patient satisfaction with information increased significantly after the liaison sister began. This was particularly notable among those admitted with an episode of cardiac pain which did not lead to myocardial infarction such as unstable angina. 77% of patients reported lack of information pre liaison sister, compared to 33% in the first 3 months after the appointment. Interestingly, the teaching given by the liaison sister also led to improved patient satisfaction with advice from other nurses and medical staff. This was perhaps because of improved understanding by the patient, the key to effective rehabilitation (unpublished data).
2. Exercise Training 2.1 Assessment Assessment for exercise training generally takes place at the 6 week review appointment. By this stage the patient who is progressing well will have
Sports Medicine 14 (4) 1992
been encouraged to walk each day up to 2 miles and, with the exception of returning to work, may have been restored to all other routine activities. It is also to be hoped that they have already significantly modified their lifestyle in terms of smoking habits, exercise and diet. Some patients will not have progressed so well and the physician may identify clinical reasons for this in terms of angina pectoris, cardiac failure or poor left ventricular function. Such assessment may be aided by carrying out an ECG and chest x-ray and by the performance of the now almost obligatory exercise tolerance test. This will identify a group of patients who require further assessment by coronary angiography with a view to revascularisation. Unless there is a delay in angiography such patients are normally not enrolled in the exercise programme at this stage, though they may of course enter it either while awaiting surgery or as postcoronary artery bypass graft patients. The exercise tolerance test may also be used to identify patients with ventricular arrhythmias induced by exercise as such patients are normally excluded from training, though it must be realised that exercise testing does not always identify those at risk of serious arrhythmias on exercise as such arrhythmias can be unpredictable in timing and provocation. However, for the majority, exercise tolerance tests provide reassurance before commencing training. Most patients are surprised that they can do so well and indeed that they are allowed to exercise in such a vigorous way. It provides both a stimulus to begin training and a benchmark against which they may assess their subsequent improvements. The physician on the other hand can categorise his patients in terms of fitness on the treadmill, presence of chest pain or ST depression and dyspnoea. While we may not have achieved sufficient sophistication to be able to prescribe an ideal programme for each type of problem, we can use this clinical information as a guide to how far and how fast to push that patient and what degree of supervision to give him. Most programmes, for example, base exercise prescription on the patient's symptom limited heart rate and this can be readily measured.
Cardiac Rehabilitation
It is usually the stable, relatively symptom free patient who is admitted to the exercise programme but extensive myocardial damage does not preclude the development of a training response and its benefits. As with normal sedentary persons it is the patient most out of condition who has most to gain from exercise and patient motivation is the vital component for success. In 1 study, patients who defaulted from an exercise programme had a reinfarction rate of approximately 50% while those who continued to exercise had a 2% recurrence rate over 3 years (Kavanagh et al. 1979).
249
erate load with frequent repetitions. Circuit training has been shown to be safe and to result in a significant increase in aerobic endurance and muscular strength (Ghilarducci et al. 1989) with in-
Table I. Victoria Infirmary power exercise training programme
Power exercises Bench press
Military press
2.2 Type of Exercise Programme After discharge, patients are advised to take short daily walks as a prelude to formal exercise training. The exercise training programme should be user friendly and encourage compliance. The sessions should start with a warm-up period and end with a cool down period (Naughton 1977). Training programmes have traditionally been aerobic exercise based, largely because this form of exercise has been extensively studied in normals and in patients with heart disease. Aerobic exercise is recommended for cardiac patients. It involves rhythmic movement of large muscle groups associated with increased cardiac output, ventilation and oxygen consumption. Strength training has been less popular and has been considered dangerous for cardiac patients because of its association with isometric exercise. The latter type of exercise causes a pressure rather than a volume load and therefore does not cause a sustained increase in cardiac output. Strength training, however, is not totally isometric as there is development of muscle tension against resistance plus movement of muscle groups with increased blood flow and cardiac output. It results in increased muscle mass, strength and cardiac size (Sparling et al. 1990). Strength training, however, has not been extensively studied in cardiac patients. Circuit training which does involve training with weights is gradually being included in rehabilitation programmes (Ghilarducci et al. 1989; Keleman et al. 1986). It involves lifting weights of mod-
Biceps curl
Upright row
Pull down
Push down
Pulley row
Quadriceps curl
Hamstrings curl
Situps
Lie on back on bench. feet on floor. equipment behind head. Raise weight by pulling bar down towards head'. Return to starting position Kneel facing equipment. Raise weight by pushing angled bar from chest level above head. fully extending arms. Return to starting position Stand facing equipment. Bend forearms to 90°. palms upwards. elbows tucked into sides. Raise weight by pulling bar uP. till arms are fully flexed. Return to starting position Stand facing equipment. Arms extended. palms downward. pull bar up towards chin. abduct upper arms so elbows move outwards. Return to starting position Sit on stool with equipment behind body. Raise weight by pulling bar down behind head. Return to starting position Stand facing equipment. Bend arms to 90° palms downwards. Raise weight by pushing bar down till arms fully extended. Return to starting position Sit on mat. legs fully extended. facing equipment. Reach for bar. Raise weight by pulling bar towards body. Return to starting position Sit on edge of bench with cushioned bar at feet equipment behind body. Flex ankle to hold bar. Raise weight by extending knees. Return to starting position Lie prone on bench. cushioned bar at feet. facing eqUipment. Rest bar on posterior aspect of ankle (Achilles tendon). Raise weight by flexing at knees while holding onto side of bench with hands to stabilise upper body. Return to starting position Lie supine on mat. legs fully extended. Grip fixed cushioned bar with feet. ankles flexed. Raise upper body. try to touch knees with forehead. Return to starting position
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creases in treadmill time in patients so trained compared with controls who continued a traditional aerobic programme (Keleman et al. 1986). Circuit weight training has been shown to be safe with regard to blood pressure response and beneficial in terms of muscle strength. We have incorporated circuit weight training in the Victoria Infirmary rehabilitation programme with no exercise related cardiac events (unpublished data). The duration, frequency and intensity of exercise training need to be considered. The duration of training in reported studies has varied from 4 weeks to several years. The optimal duration is not yet determined but a training effect can be achieved after 4 weeks' intensive aerobic exercise training (Nordrelaug et al. 1989). Most would agree that 30 to 60 minutes of exercise 2 to 3 times per week for 3 months is adequate for a training effect (Naughton 1977). Heart rate monitoring is optional but may become an obsession with some well intentioned patients. Patients should be encouraged to exercise to their own maximum perceived level of exertion by the end of their training period. This has been found to correlate well with 85% of maximum heart rate achieved on exercise testing. Patients should be started off at low levels of exercise, increasing as appropriate according to symptoms and performance to a maximum level. Most exercise training programmes are supervised on site by doctor/nurse and physiotherapist. Home based programmes have also been assessed, and while some have found them to be beneficial (Bethell et al. 1990), others have not (Palatsi 1976). They are certainly more economically viable than fully equipped gymnasiums. Patients with negative exercise tests after myocardial infarction are perhaps well suited to unsupervised exercise training. The Victoria Infirmary exercise training programme is shown in tables I and II. A wide range of aerobic exercises can be undertaken by cardiac patients. The programme we currently use is modified from the Canadian Air Force Training Programme (Royal Canadian Air Force 1973). Each patient is started off at the lowest level and advances through the levels at a rate
Sports Medicine 14 (4) 1992
Table II. Victoria Infirmary aerobic exercise training programme Aerobic exercises Arm circling Stand with feet slightly apart. Abduct arms and rotate first forwards and then backwards Stand facing step 6-10in (150-250mm) Stepups high. Step up and down at moderate pace, alternating left and right legs Trunk rotation Stand with feet slightly apart, hands on hips. Rotate trunk to right and left alternately Star jumps Stand with feet together. Jump up, abducting legs and arms fully. Return to starting position Crook lying Lie on back, arms at sides. Knees flexed. trunk rotation Rotate lower trunk from side to side Side lying hip Lie on right side, right arm stretched abduction above head, left arm supporting upper body at chest level. Right knee flexed. Abduct left leg to 90·. Return to starting position. Repeat on left side Stand with feet together, arms at sides. Standing trunk Bend at knees to lower body towards curls mat with arms stretched forwards. Return to starting position Crook lying Lie on back, knees flexed. Raise lower bridging trunk while keeping feet and shoulders on mat. Return to starting position Arm raising Stand with feet together, arms at sides, raise arms up above head. Return to starting position Trunk side Stand with feet slightly apart, arms at flexion sides. Flex trunk to right, sliding hand down right leg. Return to starting position. Repeat on left side Running on Raise feet at least 4 to 6in (100-150mm) the spot off mat, running on the spot for 1 minute
depending primarily on the symptoms. The number of repetitions of each exercise is increased over the period of training. On completing the circuit the patient finishes off the session on an exercise bicycle. Each patient's progress in the exercise class is continually assessed by a physiotherapist and rehabilitation nurse and he or she is advised about appropriate rate of progress depending on his or her performance and symptoms. Motivation is obviously paramount in such a setting - some take on more than they should, while others fail to tackle what they should be able to manage. At the end
Cardiac Rehabilitation
251
of the training period each patient should be exercising to his or her own perceived maximum level of exertion, irrespective of the form of exercise training undertaken.
Use of these muscles leads to a reflex rise in heart rate. The more work the muscle has to do, the greater the rise in heart rate. Trained muscle will respond with a smaller incremental rise, thus leading to a lesser degree of cardiac work for a given degree of peripheral work. If cardiac work is the limiting factor in patients with heart disease, then a higher degree of peripheral work may be achieved before that ceiling is reached. It is clear that the training effect is muscle specific, for example, training the leg muscles only will have no effect on the heart rate response to arm exercise (Clausen et al. 1973). Furthermore, early work suggested that a minimum duration and frequency of exercise was necessary to achieve a training effect (Pollock 1973; Pollock et al. 1972). This established the accepted guidelines for exercise training (American College of Sports Medicine 1975; American Heart Association 1972). The norm for programmes has been 3 sessions per week of 35 minutes minimum duration at 70% of maximum heart rate. The training effect may be established by periods of training as short as 4 weeks.
2.3 Benefits of Exercise Training 2.3. J Peripheral Effects The relative contributions of peripheral and central mechanisms in the training response continues to be the subject of much debate. However, the common factors in all exercise programmes leading to improved exercise tolerance are a reduction in resting heart rate and a reduction in both heart rate and systolic blood pressure at given levels of exercise after training (Clausen et al. 1969). This leads to a reduction in myocardial oxygen demand. This 'training effect' is of peripheral rather than cardiac origin. Figure 1 shows the control mechanisms responsible for such changes. The cardiovascular control area in the midbrain modulates heart rate via vagal and sympathetic efferents. Among the afferents to this control area are fibres originating in stretch receptors and skeletal muscle.
Cardiovascular control area
/
_,-+:,,@MusClekidneyandsPlanchnicarteriOles . -
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,
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Splanchnic capacitance vessels
; 8
l--:.: @ Cutaneous veins : J"\ L~~ Adrenalone (eplnephnne) Adrenal
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Fig. 1. Neurological cardiovascular control mechanisms.
