Cardiac rehabilitation: a review of its effectiveness

Coronary Health Core (1997) 1, 8 17 9 1997 Pearson Professional Ltd

REVIEW ARTICLE

Cardiac rehabilitation: a review of its effectiveness J. Pell Locum Consultant in Public Health, Greater Glasgow Health Board, Glasgow, UK SUMMARY. Despite advances in the investigation and treatment of angina and myocardial infarction, and increased knowledge of the factors associated with its development and progression, ischaemic heart disease remains the leading cause of death and morbidity in the majority of industrialized countries. Cardiac rehabilitation provides a means of modifying lifestyle and other risk factors in those presenting with established disease, thereby reducing the risk of subsequent coronary events and deaths. This article reviews the published literature on the effectiveness of cardiac rehabilitation in terms of improving mortality, quality of life and reemployment in those with myocardial infarction and stable angina pectoris.

BACKGROUND

DEFINITION OF CARDIAC REHABILITATION

Rehabilitation has been advocated for patients with a number of cardiac conditions. This happens most often for patients who have suffered a myocardial infarction (MI) (AHA 1981; De Busk 1982; Frick & Katila 1968; WHO 1993). However, there is increasing evidence of its efficacy in patients who have undergone cardiac surgery (Froelicher et al 1985; Murray & Beller 1983; Nakai 1987; Oldridge et al 1978; Tavazzi et al 1992; WHO 1993), and those suffering from heart failure (Coates et al 1990; Uren 1992) or angina (Lewin et al 1992; Lewin et al 1995; Oberman et al 1982). A British Cardiac Society working party recently recommended that every major district hospital that treats patients with heart disease should provide a rehabilitation service (Horgan et al 1992). Between 1989 and 1992, the proportion of hospitals in the UK offering rehabilitation increased from one-half to three-quarters (British Cardiac Society Working Group 1995; Horgan et al 1992), and this has continued to increase. However, the type and coverage of rehabilitation offered vary considerably.

Cardiac rehabilitation was defined previously as 'a process by which a patient is returned realistically to his greatest physical, mental, social, vocational and economic usefulness, and if employable, to employment in a competitive industrial world' (Benton 1953). With increasing rates of unemployment, the measurement of success by resumption of work has become less meaningful. Therefore, the World Health Organization more recently defined cardiac rehabilitation as 'the sum of actitivities required to influence favourably the underlying cause of the disease, as well as to ensure patients the best possible physical, mental and social conditions so that they may, by their own efforts, preserve, or resume when lost, as normal a place as possible in the life of the community' (WHO 1993). The overall aims of cardiac rehabilitation are to improve function, relieve symptoms and enhance quality of life (Chua & Lipkin 1993; WHO 1993).

EFFICACY OF CARDIAC REHABILITATION The efficacy of cardiac rehabilitation following acute MI can be assessed in terms of its impact on mortality, quality of life and re-employment.

Mortality Correspondence to: Jill Pell MSc MRCGPMFPHM,Locum Consultantin PublicHealth,GreaterGlasgowHealthBoard, 112 Ingram Street, GlasgowG1 lET, UK

A randomized trial carried out by Kallio et al (1975) demonstrated a significant reduction in mortality

Effectiveness of cardiac rehabilitation 9 following cardiac rehabilitation. Most other randomized trials have failed to demonstrate a significant effect on mortality (Carson et al 1982; Hamalainen et al 1989; Hedback & Perk 1987; Kentala 1972; Levin et al 1991; Marra et al 1985; Mayou et al 1981; Palatsi 1976; Rechnitzer et al 1983; Roman et al 1983; Shaw 1981; Vermueulen et al 1983; WHO t983; Wilhelmsen et al t975). However, the small size of most of these studies made type II statistical errors likely (Lipkin 1991). Also, follow-up tended to be short. Three early reviews suggested a favourable effect on mortality, quoting a 29% reduction over three years (May et al 1982; Naughton 1984; Shephard 1983). However, these reviews did not include all available studies, and the investigators did not perform a formal metaanalysis. Oldridge et al (1988) performed a meta-analysis of the results of 10 randomized controlled trials of cardiac rehabilitation. These encompassed a total of 4347 patients. They reported no significant effect on the rate of non-fatal MIs. However, cardiac rehabilitation was associated with a significant reduction in all-cause mortality (odds ratio (OR) 0.76) and cardiac mortality (OR 0.75). O'Connor et al (1989) performed a meta-analysis of 22 randomized controlled trials on 4554 patients. At three-years follow-up, patients undergoing cardiac rehabilitation experienced significantly better total mortality (OR 0.8), cardiovascular mortality (OR 0.78), fatal reinfarction rate (OR 0.75) and sudden death rate (OR 0.63). However, there was no significant difference in non-fatal MIs. Although these meta-analyses have been interpreted as confirming the efficacy of exercise-training, relatively few of the studies included contained only exercise training. Many studied more comprehensive rehabilitation programmes. Therefore, the benefit demonstrated may be equally attributable to risk-factor modification, or may simply be due to increased patient surveillance. Also, caution should be used in interpreting the results of meta-analyses in view of the differences between the studies included in terms of patient selection criteria, timing of rehabilitation, programme content and study population.

Quality of life In assessing rehabilitation programmes for chronic diseases, it is insufficient to consider outcome in terms of mortality and morbidity. Quality of life must also be considered. Studies applying generic quality-of-life instruments have generally shown no significant benefit following rehabilitation (Burgess et al 1987; Mayou et al 1981; Ott et al 1983; Stern & Cleary 1982; Stern et al 1983). Oldridge et al (1991) measured diseasespecific quality of life in a group undergoing a comprehensive cardiac rehabilitation programme compared to a group undergoing conventional care. At eight weeks, there was a small but significant

difference in some aspects of quality of life. However, this was not consistent across all measures and was too small to be clinically significant. By twelve months, the earlier differences had disappeared. Further evidence of a transient improvement in quality of life comes from a number of other studies (Burgess et al 1987; Mayour et al 1981; Multiple Risk Factor Intervention Trial 1982; Ott et al 1983; Stern et al 1983). In all these studies, the conventional group had comparable results by one-year follow-up.

Re-employment Return to work was previously considered an important measure of success of cardiac rehabilitation programmes. With increasing unemployment, this has become a less appropriate measure of success. Of patients in employment prior to suffering an MI, 62%-92% will return to work following rehabilitation (Shanfield 1990). However, many leave or change jobs within the following year. In a randomized trial by Dennis et al (1988), the interval prior to returning to work was only 51 days in patients undergoing a rehabilitation programme combining exercise training and occupational advice. This compared with 75 days in a control group. This reduction was not associated with any adverse medical sequelae. Patients' attitudes towards return to work in the acute phase of the illness is a powerful predictor of subsequent employment. Except in the case of patients with persistent angina or heart failure, failure to return to work is more often due to psychological or financial considerations than to statutory or physical constraints. Even in occupations where health standards are prescribed by statute, there is an increasing move away from arbitrary standards towards an individual assessment of risk and capacity (Irving & Petch 1994; Picard et al 1989).

ECONOMIC EVALUATION OF CARDIAC REHABILITATION Coronary artery disease costs the National Health Service s million annually in treatment (TunstallPedoe 1991). It accounts for 12% of sick-leave, producing a further cost of s in lost productivity (Tunstall-Pedoe 1991). A cardiac rehabilitation session costs s163 per patient (Horgan et al 1992). A US cost-utility study of a comprehensive rehabilitation programme for patients suffering from moderate anxiety or depression following MI (Otdridge et al 1993) produced a cost per qualityadjusted life-year (QALY) of $9200. This compared favourably with costs of $3100 and $5300 for aspirin therapy and beta blockade respectively. The authors concluded that cardiac rehabilitation has been shown to be economically justified. However, many of the control group attended some form of rehabilitation.

10

Coronary Health Care

Also, the results cannot be assumed to be similar in all patients suffering MI. In a Swedish study, 51% of patients undergoing comprehensive cardiac rehabilitation were in employment 5 years following MI, compared to only 27% of controls. Patients undergoing rehabilitation suffered fewer cardiac events and less anxiety and depression. This resulted in fewer readmissions. The cost of the rehabilitation programme was offset by the lower rate of admission. Higher rates of employment in the rehabilitation group produced a net societal saving of $10 000 per patient (Levin et al 1991). Other studies have confirmed a reduction in readmissions, shorter lengths of stay during readmission, fewer cardiac events and marginally lower costs following rehabilitation (Ades et al 1992; Picardi et al 1989). However, none of these was a randomized trial. In a recent review, Chu and Lipkin (1993), concluded that 'cardiac rehabilitation programmes are cost effective and should be made available to all who would benefit'.

ventricular arrythmias, uncontrolled hypertension and severe aortic stenosis (Chua & Lipkin 1993; Siegel et al 1988). Age per se is not an absolute contraindication, although it imposes obvious constraints if associated with poor mobility or comorbidity (Siddiqui 1992).

STRUCTURE AND CONTENTS OF CARDIAC REHABILITATION

9 a reduction in heart rate and blood pressure at rest and during exercise; 9 increased high-density lipoprotein (HDL) cholesterol levels (Hartung et al 1981); 9 improved glucose tolerance in diabetic patients (Pedersen et al 1980); 9 enhanced fibrinolysis in response to thrombotic stimuli (Williams et al 1980); 9 improvements in electrocardiographic ST segment changes (Detry & Bruce 1971; Todd and Ballantyne 1992); 9 improvements in ejection fraction (Ehsani et al 1986); and 9 a higher ischaemic threshold (Ehsani et al 1986).

Provision of cardiac rehabilitation varies greatly between hospitals (Horgan et al 1992). There is little consistency in the level of funding, selection criteria or programme content (Horgan et al 1992). Most early programmes concentrated on exercise training. However, it is now agreed that a more comprehensive approach should be taken, including secondary prevention, relaxation, education, stress management, and psychosocial adjustment (WHO 1993). Partners and other close family members should be involved in the rehabilitation process (WHO 1993). Cardiac rehabilitation should begin at the time of diagnosis of coronary artery disease, or as soon as possible following admission with an acute event (WHO 1993). In practice, patients are usually recruited to programmes 4-8 weeks post MI and attend for 4-12 weeks (Horgan et al 1992). Cardiac rehabilitation should be available to all suitable patients, but limited resources often necessitate prioritization. There is a lack of conclusive research evidence on which types of patient benefit most from cardiac rehabilitation, the ideal time at which to commence programmes, and the effect of newer treatments such as thrombolysis and angioplasty on outcome following rehabilitation (Oberman 1989). Nonetheless, it has been suggested that the patients who might benefit most from inclusion are those who have multiple cardiac risk factors, a low exercise capacity, are slow to adjust psychologically to a new lifestyle or have had recent cardiac surgery (Chua & Lipkin 1993). Contraindications to exercise training include unstable angina pectoris,

Exercise training There is epidemiological evidence that increased physical activity is associated with a lower risk of atherosclerotic heart disease (Paffenbarger & Hyde 1984; Rodriguez et al 1994). Exercise training can be beneficial in preventing the development and progression of ischaemic heart disease. Studies have shown a number of benefits from exercise training following MI or coronary artery bypass graft (CABG) including an 11%-66% increase in maximal functional capacity and greater myocardial contractility (Diagnostic and Therapeutic Technology Assessment 1987; Greenland 1988; Oberman 1988). Other benefits of exercise training include:

Exercise training can also be effective in long-term weight-reduction and hypertension control (Laslett et al 1987; Wenger & Brest 1985) which may lead to additional benefits in cardiovascular morbidity and mortality rates. However, not all exercise trials have reported such benefits. Some have reported negative outcomes (Froelicher 1984; Grodzinski 1987; Shephard 1986; Wenger 1979). The safety of exercise training was assessed by van Camp and Peterson (1978) who reviewed the complication rates in more than 51 000 patients. They calculated that MIs occurred at a rate of 3.4 per million patient-hours of exercise, cardiac arrests at a rate of 8.9 per million patient-hours and fatalities at 1.3 per million patient-hours. Approximately one month following MI, most patients experience a spontaneous improvement in functional capacity that does not seem to be related to previous activity levels (DeBusk 1979; Wohl et al 1977). Patients who participate in formal exercise

Effectiveness of cardiac rehabilitation 11 programmes achieve their optimum functional state more rapidly than patients who do not (DeBust et al 1985; Greenland & Chu 1988; Hung et al 1994), have fewer visits to their doctors and hospitals (Ades et al 1992) and are more likely to return to work (Boudrez et al 1994). The effects of exercise training increase in an S-shaped curve and plateau at about 13-14 weeks (A1-Khawaja 1992). The potential benefits of exercise training are not restricted to patients who have suffered acute MIs or undergone CABG. Patients with angina can benefit by experiencing fewer symptoms and increased exercise capacity (Ehsani et al 1986; Todd & Ballantyne 1992). Patients with impaired left ventricular function have also reported symptomatic improvement following exercise training (Sullivan et al 1988). Some patients with congestive heart failure show improved functional capacity, although the results are unpredictable in individual patients (Hedback & Perk 1990; Tristani et al 1987). Both light and heavy exercise have been shown to have beneficial effects on physical performance following MI (Goble et al 1991). However, the ideal types of exercise to improve cardiovascular fitness are now well characterized. Patients are advised to participate in moderate, rather than high-intensity, exercise sustained for periods of about 20 min and repeated regularly (Thompson et al 1994). Pre-exercise assesessment is important in devising an appropriate exercise programme and detecting potential risks. Formal treadmill exercise testing is useful for preexercise assessment and for monitoring progress. Patients with arthritis, heart failure or respiratory disease may find treadmill testing difficult. For these patients, timed corridor or shuttle-walk tests are an alternative. Hospital patients can be taught simple ways of self-assessing physical activity, such as pulserate measurement and the Borg perceived exertion test prior to discharge (Borg 1982). Exercise prescription should be done at the individual patient level in order to take account of the underlying disease and the patient's own requirements and targets. Low-risk patients do not need to participate in formal programmes, but can perform exercises at home with the aid of rehabilitation manuals and audiotapes (Lewin et al 1992). The meta-analyses conducted by Oldridge et al (1993) and O'Connor et al (1989) have been cited as evidence of the efficacy of exercise programmes following MI. However, as mentioned previously, many of the studies were of comprehensive programmes rather than exercise training alone. The fall in mortality demonstrated was primarily due to an effect on sudden death, rather than reinfarction. Sudden death has been shown to be primarily related to psychosocial factors, unlike non-sudden death, which is associated with medical variables (Brackett 1988). Exercise alone does not produce long-term improvements in psychosocial adjustment (Mayou 1981; Naughton

1973; O'Rourke 1991; Plavsic 1976; Stern 1982). Therefore, the improvement in mortality demonstrated by the meta-analyses may be accounted for by the non-exercise components of the studies reviewed. Exercise-only programmes have also failed to demonstrate a long-term effect on rates of re-employment (Danchin 1988). Compliance with exercise training programmes is poor. Up to 50% of patients drop out of programmes before the end (Dischhor 1989). Follow-up studies have reported that less than two thirds of patients attend more than 70% of sessions, and as few as 30% are still exercising at one year (Furberg & May 1984; Kentala 1972; Oldridge 1988; Palasti 1976; Rechnitzer et al 1983; Shaw 1981). A comparable figure has been reported among patients not undergoing cardiac rehabilitation (Stern & Cleary 1982).

Risk-factor modification The major modifiable risk factors for recurrent cardiac events are the same as those for the initial development of coronary arterial disease, and include hypertension, smoking, increased serum cholesterol levels, inactivity and obesity. Lifestyle changes can be beneficial in both primary and secondary prevention (Lovibond et al 1986; Patel et al 1985). Comprehensive lifestyle changes, without the addition of lipid-lowering drugs, can be sufficient to produce angiographic evidence of disease regression at one year, even in patients with severe disease (Ornish et al 1990). Secondary prevention programmes have also been shown to reduce the likelihood of recurrent cardiac events (Siegel et al 1988), as well as reducing cardiovascular mortality (Multiple Risk Factor Intervention Study 1985) and sudden deaths (Hamalainen et al 1989). However, no benefit has been demonstrated in non-fatal MI. MI survivors are generally well motivated to change their lifestyles. Studies have demonstrated that dietary interventions can lower serum cholesterol levels by as much as 17%~22% (Research Committee 1965 & 1968). Similarly, smoking cessation rates of 50%-70% can be achieved in post-MI survivors, even without special smoking cessation programmes (Mulcahy 1983; Wilhelmsson et al 1975). However, patients with lower levels of education have a poorer prognosis following MI (Weinblatt 1978) and are less successful at modifying risk factors (Conroy et al 1986; Reid et al 1984).

Smoking cessation Cigarette-smoking is a widely recognized risk factor for the development of coronary artery disease (Saons 1986), and continued smoking following MI doubles the risk of a recurrent cardiac event (Rosenberg 1985). There have been no randomized controlled trials of the effect of quitting smoking on

12

Coronary Health Care

the outcome following MI. However, observational studies suggest that continuing to smoke is associated with a relative risk of subsequent death of 1.6-1.9 (Hickey et al 1983; Mulcahy et al 1977; Salonen 1980; Sparrow & Dawber 1978; Wilhelmsson et al 1975; Wilhelmsen 1983). In addition to reducing the risk of recurrent cardiac events and death, quitting smoking confers additional beneficial effects in terms of the risk of angina, congestive heart failure, intermittent claudication and many other conditions (Siegel et al 1988). Smoking cessation should be a goal of any comprehensive cardiac rehabilitation programme. Programmes that address nicotine addiction and the behavioural aspects of smoking appear to be the most effective (Garvey et al 1989). Abstinence rates of 60% 80% one year post MI have been reported for some formal programmes (Higgins & Schweiger 1983; Taylor et al 1988). These are significantly better than the result achieved for patients not recruited to such programmes. The benefits of smoking cessation should be stressed during the convalescent period when patients are most motivated (Siegel et al 1988).

Management of hypertension One function of cardiac rehabilitation is to educate patients regarding the necessity of compliance with long-term medication. Patients who remain hypertensive post MI have a greater risk of subsequent death compared with normotensive patients (Kannel et al 1980). Treatment of hypertension following MI has been demonstrated to produce a 20% reduction in total mortality (Langford et al 1986).

Management of hypercholesterolaemia Elevated cholesterol levels are a risk factor for further cardiac events following acute MI, especially in patients under 50 years of age (The Coronary Drug Project Research Group 1978). Both dietary and drug treatments have been shown to effectively lower serum cholesterol (Artzenius et al 1985; The Expert Panel 1988). Lowering low-density lipoprotein (LDL) cholesterol and raising HDL cholesterol have been shown to be associated with delayed progression, stabilization or regression of coronary atherosclerosis in several studies (Blankenhorn et al 1987; Brensike et al 1984; Grundy et al 1989). Treatment of hypercholesterolaemia significantly decreases the risk of MI and sudden cardiac death (Lipid Reseach Clinics Program 1984 a&b) as well as reducing mortality following MI (Canner et al 1986). The recent 4S study (1994) demonstrated that treatment of moderate hypercholesterolaemia with simvastatin in patients with angina or previous MI resulted in a 42% reduction in the risk of coronary death and a 30% reduction in total mortality. In addition, a 37% reduction in the need for myocardial revacularization procedures was observed.

Weight-reduction There have been no randomized controlled trials of weight-reduction in MI survivors, but it has been recommended that patients more than 20% above the mid-range of desirable weight would benefit from a weight-reduction programme (Siegel et al 1988).

Psychological interventions Coronary arterial disease is often associated with adverse psychological sequelae, which may lead to undue illness behaviour and avoidable use of health resources (Maeland 1989; Lloyd 1983). The development of psychological symptoms is dependent on the way in which a patient adapts to the disease, and is not related to infarct size or any other measure of cardiac status (Fraser-Smith 1991; Kallio & Cay 1985; Ladwig et al 1992). For most patients, the main obstacles to recovering an acceptable quality of life following infarction are psychological, not social or physical (Kallio 1985). Following infarction, the frequency of self-reported chest pain (Smith 1984; Jenkins 1983), success of medical (Williams 1986) and surgical treatment (Charmer 1988), use of medical resources (Maeland 1989a) and return to work (Danchin 1988) are all related to psychological measures such as anxiety, depression, cardiac misconceptions, hypochondriasis, anger and sleep disturbance, rather than to measures of disease. There is also increasing evidence that psychological distress following MI is an independent predictor of early mortality (Brackett 1988; Frasure-Smith 1991; Garrity 1975; Carney 1988; Ruberman 1984). A poor rehabilitation outcome has been shown to be associated with the following: 9 9 9 9 9 9 9

a history of anxiety or depression; lower educational level; socioeconomic deprivation; perceived health status; perceived stress; social isolation; and personality variables, such as hypochondriasis, neuroticism and a 'passive fearful coping style' (Davey-Smith 1990; Lewin B, personal communication; Maeland 1990; Ruberman 1984).

Patients suffering social isolation and high levels of stress have four times the risk of death over the three years following MI (Ruberman 1984). The most important predictors of compliance and outcome are the patient's beliefs about the causation and course of the disease, and the number of misconceptions held (Maeland 1989). Approximately 80% of patients blame 'stress', 'worry' or 'overwork' as the primary reason for illness. Patients often believe that the heart is 'worn out' and therefore fear that activity will damage the heart by producing a 'mini heart attack' in the form of angina. For some patients, their lives centre around the illness (Julian 1992).

Effectiveness of cardiac rehabilitation 13 A poor psychological outcome following MI is not inevitable. In most patients, the psychological reactions are transient. Twenty per cent report a spontaneous improvement in their quality of life following MI (Laerum 1988). However, persistent depression and anxiety occur in 20%-30% of patients (Cay 1972; Lloyd 1983). Other family members can also react badly and this, in turn, can have an adverse effect on the patient's response (Cay 1982). These symptoms are easily detected and usually respond well to simple counselling, aimed at addressing concerns and correcting misconceptions (Thompson 1990). Early, careful and consistent explanation can help to prevent these complications. A significant reduction in cardiac events five years post MI has been shown following interventions aimed at reducing stress in those in whom levels are highest (Frasure-Smith 1991). A home-based selfhelp rehabilitation programme designed to alter patients' beliefs about the cause and course of the disease reduced psychological distress by 50% and led to fewer readmissions to hospital and visits to general practitioners in the following year (Lewin 1992). Adding relaxation training to a post-MI programme can improve exercise training success by 50%, as well as significantly reducing ST segment abnormalities (Dixhoorn 1989). Over a three-year follow-up period, Dixhoorn (1987) reported cardiac events in 37% of patients undergoing exercise training alone, compared to only 17% in those who also underwent relaxation therapy. Stress management techniques (SMTs) are an extension of relaxation and teach additional techniques for dealing with stress. SMTs produce still further benefits in terms of cardiac events and deathrate post MI (Langosh 1984; Frasure-Smith 1989). A programme combining moderate home-based exercise, education and SMTs produced a 70% reduction in angina, a functionally significant increase in exercise capacity and a reduction in surgery costs (Lewin et al 1995). In a study of SMTs, exercise and education, Ornish (1990) reported a 90% reduction in the frequency of angina, in addition to angiographic evidence of regression of atherosclerosis in 82% of patients. Patient education

One of the principle aims of cardiac rehabilitation is the restoration of patients' confidence to enable them to resume normal activities. Therefore, education and support for patients and family members is considered a cornerstone of cardiac rehabilitation. Educational programmes should be centred around clear, specific items for discussion, covering the diagnosis and its implications, medication and its effects, and available support if needed. Co-ordination is needed to avoid conflicting advice. The educational impact can be increased by using a variety of media. Written and taped information should enforce verbal

communication (Lindsay et al 1991) and should be available if required in appropriate languages. Education programmes for patients and partners improve knowledge (Steele & Ruzicki 1987; Raliegh & Odtohan 1987), decrease disability (Hogan & Neill 1983) and produce short-term changes in health behaviours. However, in most individuals, education alone does not lead to improved long-term changes in smoking (Sivarajan 1983), diet (Barbarowicz 1980), or level of physical activity (Oldridge 1988; Martin 1984). Education can reduce anxiety and depression but, in isolation, is unlikely to prevent psychological disturbance in all patients (Horlick 1984). Cognitive behavioural treatments appear to be a more promising method for producing changes in lifestyle. They encourage patients to examine beliefs and motivations and to recognize the environmental factors maintaining their unwanted behaviours. Most importantly, they involve patients in sytematically practising new behaviours. Exercise programmes which incorporate such techniques have demonstrated considerable gains in long-term compliance with exercise (Oldridge et al 1988), weight-loss (Brownell 1987) and smoking cessation (Glasgow 1987). A controlled trial assessing cognitive behavioural therapy in primary prevention produced a 41% reduction in coronary arterial disease incidence at one year (Lovibond 1986).

CARDIAC REHABILITATION OF PATIENTS WITH STABLE ANGINA There has been increasing interest in the use of cardiac rehabilitation for patients with chronic stable angina. Exercise training reduces the submaximal heart rate of patients with ischaemic heart disease and hence increases the level of work required to produce angina (Sim & Neil 1974). Therefore, exercise training can improve exercise tolerance, and reduce the frequency of symptoms (Clausen et al 1969; Ehsani 1986; Ehsani et al 1986; Rarfo et al 1980 a&b; Redwood et al 1972; Schuler et al 1988; Ornish 1990). Most studies have concentrated on assessments of left ventricular function or perfusion. In 1972, Redwood et al showed that exercise training increased the maximum heart rate of patients with angina, and resulted in a 13% rise in their triple product.* This result has been corroborated by more recent studies (Ehsani et al 1981 & 1986; Jensen et al 1980; Rarfo et al 1980b; Tubau et al 1982; Winter et al 1984). Although these results have been refuted by some studies, these have mostly used much lower levels of exercise (Clausen & Trap-Jensen 1976; Dressendorker et al 1982; Nolewadika et al 1979). Other studies have assessed the effect of exercise on electrocardiograph (ECG) criteria of disease 9 h e a r t rate x systolic b l o o d pressure x ejection time

14

Coronary Health Care

severity. Exercise training has been shown to reduce m a x i m u m ST depression, suggesting that the improvement in heart rate associated with exercise is not simply due to a decreased pain threshold (Ehsani et al 1981; Todd & Ballantyne 1990). Todd and Ballantyne (1990) compared the effect of daily exercise training with that of beta blockade in 40 men under 60 years of age who presented with chronic stable angina of at least six months' duration and who had no history of MI. Exercise training increased m a x i m u m heart rate, m a x i m u m double product* and double product ST threshold *t by 8%, 11% and 12% respectively. Conversely, beta blockade produced decreases in all these measures by 15%, 7% and 22% respectively. Exercise training produced a greater improvement in exercise tolerance than atenolol. SMTs can also produce substantial symptomatic relief in patients with chronic stable angina (Ornish 1990). A home-based rehabilitation programme including SMTs demonstrated a 70% reduction in episodes of angina, 65% reduction in the use of nitrates, 72% reduction in self-reported disability, 57% improvement in exercise tolerance and a significant improvement in the time to 1 m m ST depression (Lewin 1995). These benefits were maintained at one year, and 50% of patients awaiting elective C A B G could be removed from the list. Rehabilitation of patients awaiting C A B G has also been shown to increase the numbers returning to work following surgery (Oberman et al 1982). DISCUSSION Coronary artery disease is a leading cause of morbidity and mortality in developed countries. It accounts for more than s million of N H S expenditure each year (Tunstall-Pedoe 1991). Cardiac rehabilitation provides a means of modifying lifestyle and other risk factors in patients with cardiac disease with the aim of reducing coronary events and deaths, and improving symptoms and quality of life. The case for cardiac rehabilitation is best established for those who have suffered an MI. In metaanalyses performed by both Oldridge et al (1988) and O ' C o n n o r et al (1989), cardiac rehabilitation was demonstrated to be associated with reductions in both cardiac and all-cause mortality. Although shortterm benefits were demonstrated in quality of life, these were not sustained at one year. Cost utility analyses have produced figures comparable with many other routinely offered treatments (Oldridge et al 1995). Cardiac rehabilitation can produce financial savings through reductions in readmission rates and improvements in re-employment (Ades et al 1992; Levin et al 1991; Picardi et al 1989). t heart rate x systolicblood pressure **double product at which 1 mm of horizontal or downsloping ST depression was first recorded

Although proponents have supported the effectiveness of exercise training (Ehsani et al 1986; O b e r m a n 1988; Todd & Ballantyne 1992), risk-factor modification (Langford et al 1986; Scandinavian Simvastatin Survival Study G r o u p 1994; Siegel et al 1988), patient education and psychological interventions (FrasureSmith 1991; Lewin et al 1995; Ornish 1990) when used in isolation, most authorities would now recommend a combined approach to cardiac rehabilitation incorporating all of these approaches. Evidence is now accumulating to support the use of cardiac rehabilitation in other groups of patients suffering from cardiac disease, including those with angina (Lewin et al 1992; O b e r m a n et al 1982) or cardiac failure (Coates et al 1990; Uren 1992) and those who have undergone cardiac surgery (Froelicher et al 1985; Tavazzi et al 1992). A British Cardiac Society working party advocated that all hospitals treating patients with cardiac disease should offer rehabilitation (Horgan et al 1992). Although the numbers of hospitals offering cardiac rehabilitation has increased greatly over the last decade (British Cardiac Surgery Working G r o u p 1995; Horgan et al 1992), there is some evidence that m a n y patients are still not invited to rehabilitation (Pell et al 1996). Greater efforts are still required to increase the coverage of cardiac rehabilitation. REFERENCES

Ades PA, Huang D, WeaverMS 1992 Cardiac rehabilitation participation predicts Sowerrehospitalisation costs. American Heart Journal 123:916-921 A1-Khawaja I 1992 Benefits and risks of cardiac rehabilitation. Cardiology in Practice 10:20-21 American Heart Association Council on ScientificAffairs 1981 Physician supervised exerciseprograms in rehabilitation of patients with coronary heart disease. Journal of the American Medical Association 245:1436-1436 Artzenius AC, Krombout D, Barth JD et al 1985 Diet, lipoproteins and progression of coronary atherosclerosis: the Leiden intervention trial. New England Journal of Medicine 312:805 811 Barbarowicz R Nelson M, De Busk RF, Haskell WL 1980 A comparison of in-hospital education approaches for coronary bypass patients. Heart and Lung 9:127 133 Benton JG, Rusk HA 1953 Patients with cardiovasculardisease and rehabilitation: third phase of medical care. Circulation 8: 417426 Borg G 1982 Psychophysicalbasis of perceivedexertion. Medicine and Science in Sports and Exercise 14:377-381 Bourdes H, De Backer G, Comhaire B 1994 Return to work after myocardial infarction: results of a longitudinal population based study. European Heart Journal 15:32-36 Brackett CD, Powell LH 1988 Psychologicaland physiological predictors of sudden cardiac death after healing of acute myocardial infarction. American Journal of Cardiology 61: 979-983 Brenzike JF, Levy RI, Kelsey SF et al 1984 Effects of therapy with cholestyramine on progression of coronary atherosclerosis: results of the NHLBI type II coronary intervention study. Circulation 69:313 324 British Cardiac SocietyWorking Group 1995 Cardiac rehabilitation servicesin the United Kingdom 1992. British Heart Journal 73:201 202 Brownell CD, Powell LH 1988 Psychosocial and physiological predictors of sudden cardiac death after healing of acute myocardial infarction. American Journal of Cardiology 61: 979-983

Effectiveness of cardiac rehabilitation

Burgess AW, Lerner D J, D'Agostino RB, Vokonas PS, Hartman CR, Gaccione P 1987 A randomised control trial of cardiac rehabilitation. Social Science and Medicine 24:359-370 Canner PL, Berge KG, Wenger NK et al 1986 Fifteen year mortality in coronary drug project patients: long-term benefit with niacin. Journal of the American College of Cardiology 8:1245 1255 Carney RM, Rich MW, Freeland KE, Saini J 1988 Major depressive disorder predicts cardiac events in patients with coronary artery disease. Psychosomatic Medicine 50:627-633 Carson P, Philips R, Lloyd M et al 1982 Exercise after a myocardial infarction: a controlled trial. Journal of the Royal College of Physicians (Lond) 16:141 147 Cay EL 1982 Psychological problems in patients after a myocardial infarction. Adv Cardiol 22:108 112 Cay EL, Vetter N, Philip A, Dugard P 1972 Psychological status during recovery from an acute heart attack. Journal of Psychosomatic Research 16:425435 Channer KS, O'Connor S, Britton S 1988 Psychological factors influence the success of coronary artery surgery. Journal of the Royal Society of Medicine 11:629~532 Chua TP, Lipkin DP 1993 Cardiac rehabilitation should be available to all who would benefit. British Medical Journal 306:731-732 Clausen JP, Trap-Jensen J 1976 Heart rate and arterial blood pressure during exercise in patients with angina pectoris: effects of training and of nitroglycerin. Circulation 53:436442 Clausen JP, Larsen DA, Trap-Jensen JT 1969 Physical training in the management of coronary artery disease. Circulation 40: 143 154 Coates AJS, Adamopoulos S, Meyer TE, Conway J, Sleight P 1990 Effects of physical training in chronic heart failure. Lancet 355:63 66 Collins R, Yusuf S, Peto R 1984 Exercise after myocardial infarction reduces mortality. Evidence from randomised controlled trials. Journal of the American College of Cardiology 3:622 Conroy RM, Cahill S, Mulcahy R, Johnson H, Graham IM, Hickey N 1986 The relation of social class to risk factors, rehabilitation, compliance and mortality in survivors of acute coronary disease. Scandinavian Journal of Social Medicine 14:51 56 Danchin N, Goepfert PC 1988 Exercise training, cardiac rehabilitation and return to work in patients with coronary artery disease. European Heart Journal 9:43~16 Davey-Smith G, Bartley M, Blane D 1990 The Black report on socio-economic inequalities in health 10 years on. British Medical Journal 301:373 377 De Busk RF 1982 Physical conditioning following myocardial infarction. Advances in Cardiology 31:156-161 De Busk RF, Houston N, Haskell W, Fry G, Parker M 1979 Exercise training soon after myocardial infarction. American Journal of Cardiology 44:1223-1229 De Busk RF, Haskell WL, Miller NH et al 1985 Medically directed at-home rehabilitation soon after clinically uncomplicated acute myocardial infarction. A new model for patient care. American Journal of Cardiology 55:1524-1528 Dennis C 1991 Cost-effectiveness in cardiac rehabilitation. Journal of Cardiopulmonary Rehabilitation 11:128-131 Dennis C, Houston-Miller N, Schwartz RG et al 1988 Early return to work after uncomplicated myocardial infarction: results of a randomised trial. Journal of the American Medical Association 260:214-220 Detry J, Bruce RA 1971 Effects of physical training on exertional ST segment depression in coronary heart disease. Circulation 4: 390 Diagnostic and Therapeutic Technology Assessment (DATTA) 1987 Coronary rehabilitation services. Journal of the American Medical Association 258:1959-1962 Dixhoorn van J, Duivenvoorden H J, Staal HA et al 1987 Cardiac events after myocardial infarction: possible effect of relaxation therapy. European Heart Journal 8:121 0-1262 Dixhoorn van J, Duivenvoorden H J, Staal HA, Pool J 1989 Physical training and relaxation therapy in cardiac rehabilitation assessed through a composite criterion for training outcome. American Heart Journal 118:545-552 Dressendorfer RH, Smith JL, Amsterdam EA, Mason DT 1982 Reduction of submaximal exercise myocardial oxygen demand

15

post-work training program in coronary patients due to improved physical work efficiency. American Heart Journal 103:358 362 Ehsani AA 1986 Altered adaptive responses to training by nonselective beta adrenergic blockade in coronary artery disease. American Journal of Cardiology 58:220~224 Ehsani AA, Heath GW, Hagberg JM et al 1981 Effects of 12 months of intense exercise training on ischaemic ST-segment depression in patients with coronary artery disease. Circulation 64:1116-1124 Ehsani AA, Biello DR, Schultz J, Sobel BE, Holloszy JO 1986 Improvement of left ventricular contractile function by exercise training in patients with coronary artery disease. Circulation 74:350-358 Frasure-Smith N 1991 In-hospital symptoms of psychological stress as predictors of long-term outcome after acute myocardial infarction in men. American Journal of Cardiology 67:121 127 Froelicher V, Jensen D, Sullivan M 1985 A randomised trial of the effects of exercise training after coronary artery bypass surgery. Archives of Internal Medicine 145:689~592 Frick MH+ Katila M 1968 Hemodynamic consequences of physical training after myocardial infarction. Circulation 37:192 202 Friedman M, Thoreson CE, Gill JJ et al 1986 Alteration of type A behaviour and its effect on cardiac recurrences in post myocardial infarction: summary results of the recurrent coronary prevention project. American Heart Journal 112: 653 655 Furberg CD, May GS 1984 Effect of long-term prophylactic treatment on survival after myocardial infarction. American Journal of Medicine 76:76-83 Garrity TF, Klein RF 1975 Emotional response and clinical severity as early determinants of six-month mortality after myocardial infarction. Heart and Lung 4:730-737 Garvey A J, Heinold JW, Rosner B 1989 Self-help approaches to smoking cessation: a report from the normative ageing study. Addictive Behaviors 14:23 34 Glasgow RE, Lichtenstein E 1987 Long term effects of behavioural smoking cessation interventions. Behavioral Therapies 18:297 324 Goble A J, Hare DL, Macdonald PS, Oliver RG, Reid MA, Worcester MC 1991 Effect of early programmes of high and low intensity exercise on physical performance after transmural acute myocardial infarction. British Heart Journal 65:126-131 Greenland P, Chu JS 1988 Efficacy of cardiac rehabilitation services: with emphasis on patients after myocardial infarction. Annals of Internal Medicine 109:650-653 Grundy SM, Goodman DS, Rifkind BM et al 1989 The place of HDL in cholesterol management: a prospective from the National Cholesterol Education Program. Archives of Internal Medicine 149:505 510 Hamalainen H, Luurila OJ, Kallio Vet al 1989 Long term reduction in sudden deaths after a multifactorial intervention programme in patients with myocardial infarction: 10 year results of a controlled investigation. European Heart Journal 10:55~52 Hartung GH, Squires WG, Gotto AM 1981 Effect of exercise training on plasma high-density lipoprotein cholesterol in coronary disease patients. American Heart Journal 101: 181 184 Hedback B, Perk J 1987 Five-year results of a comprehensive rehabilitation programme after myocardial infarction. European Heart Journal 8:234-242 Hedback B, Perk J 1990 Can high risk patients after myocardial infarction participate in comprehensive cardiac rehabilitation? Scandinavian Journal of Rehabilitation Medicine 2:15 20 Hellerstein HK. Ford AB 1957 Rehabilitation of the cardiac patient. Journal of the American Medical Association 164: 225-231 Higgins C, Schweiger MJ 1983 Smoking termination patterns in a cardiac rehabilitation population. Journal of Cardiac Rehabilitation 3:55-59 Hogan CA, Neill WA 1983 Effect of a teaching programme on knowledge, physical activity and socialisation in patients disabled by stable angina pectoris. Journal of Cardiac Rehabilitation 2:379 384 Horgan J, Bethell H, Carson P et al 1992 Working party report on cardiac rehabilitation. British Heart Journal 67:412~118

16

CoronaryHealth Care

Horlick L, Cameron R, Firor W e t al 1984 The effects of education and group discussion in the post myocardial infarction patient. Journal of Psychosomatic Research 28: 485-492 Hung J, Gordon EP, Houston N, Haskell WL, Goris ML, De Busk RF 1994 Changes in rest and exercise myocardial perfusion and left ventricular function 3 to 26 weeks after clinically uncomplicated acute myocardial infarction: effects of exercise training. American Journal of Cardiology 54: 943 950 Irving JB, Petch MB 1994 Fitness to drive: updated guidelines for cardiovascular fitness in vocational drivers. Health Trends 26: 38-40 Jenkins DC, Stanton B, Klien MD et al 1983 Correlates of angina pectoris amongst men awaiting coronary artery bypass surgery. Psychosomatic Medicine 45:141-153 Jensen D, Atwood JE, Froelichner Vet al 1980 Improvement in ventricular function during exercise studied with radionuclide ventriculography after cardiac rehabilitation. American Journal of Cardiology 46:77~777 Julian D G 1992 Cardiology, 6th edn. Bailli6re Tindall, London Kallio V, Cay E 1985 Rehabilitation after myocardial infarction. The European experience. WHO Regional Office for Europe, Geneva Kallio V, Hamalaiainen H, Hakkila J, Luurila OJ 1979 Reduction of sudden deaths by a multifactorial intervention program after myocardial infarction. Lancet ii: 1091-1094 Kannel WB, Sorlie P, Castelli WP, McGee D 1980 Blood pressure and survival after myocardial infarction: the Framingham study. American Journal of Cardiology 45:326-330 Kantala E 1972 Physical fitness and feasibility of physical rehabilitation after myocardial infarction in men of working age. Annals of Clinical Research 4 (Suppl 9): 1 84 Laerum E, Johnsen N, Smith P, Larsen S 1988 Myocardial infarction may induce positive changes in life-style and in quality of life. Scandinavian Journal of Primary Health Care 6:67 71 Lagwig KH, Lehmacher W, Roth R, Breithardt G, Budde TH, Borggraefe M 1992 Factors which provoke post infarction depression: results from the post-infarction late potential (PILP) study. Journal of Psychosomatic Research 36:723 729 Langford HG, Stamler J, Wassertheil-Smoller S, Prinease RJ 1986 All cause mortality in the hypertension detection and followup program: findings for the whole cohort and for persons with less severe hypertension, with and without other traits related to the risk of mortality. Progress in Cardiovascular Diseases 29 (Suppl 1): 29 54 Langosch W 1984 Behavioural interventions in cardiac rehabilitation. In: Health Care and Human Behaviour. Academic Press, London, pp 301 324 Laslett L, Paumer L, Amsterdam EA 1987 Exercise training in coronary artery disease. Cardiology Clinics 5:211 225 Levin LA, Perk J, Hedback B 1991 Cardiac rehabilitation cost analysis. Journal of Internal Medicine 230:427-434 Lewin B, Robertson IH, Cay WL, Irving JB, Campbell M 1992 Effects of self-help post-myocardial infarction rehabilitation on psychological adjustment and use of health services. Lancet 339:1036-1040 Lewin B, Cay E, Todd I et al 1995 The angina management programme: a rehabilitation treatment for chronic angina pectoris. British Journal of Cardiology 2:221~26 Lindsay C, Jennrich JA, Biernolt M 1991 Programmed instruction booklet for cardiac rehabilitation teaching. Heart and Lung 20:638-653 Lipid Research Clinics Program 1984a The lipid research clinics coronary primary prevention trial results. I. Reduction in incidence of coronary heart disease. Journal of the American Medical Association 251:351-364 Lipid Research Clinics Program 1984b The lipid research clinics coronary primary prevention trial results. II. The relationship of reduction in incidence of coronary heart disease to cholesterol lowering. Journal of the American Medical Association 25:365 374 Lipkin DP 1991 Is cardiac rehabilitation necessary? British Heart Journal 65:23%238 Lloyd GG, Cawley RH 1982 Distress of illness? A study of psychological symptoms after myocardial infarction. British Journal of Psychiatry 142:120-125

Lovibond SH, Birrell P, Langeluddeck P 1986 Changing coronary heart disease risk-factor status: the effects of three behavioural programs. Journal of Behavioural Medicine 9: 415-437 Maeland JG, Havik OE 1989a Use of health services after a myocardial infarction. Scandinavian Journal of Social Medicine 17:93-102 Maeland JG, Havik OE 1989b After the myocardial infarction. A medical and psychological study with special emphasis on perceived illness. Scandinavian Journal of Rehabilitation Medicine Suppl 22:1 87 Marra S, Paolillo V, Spadacculi F et al 1985 Long-term follow-up after a controlled randomised post-myocardial infarction rehabilitation programme: effects on morbidity and mortality. European Heart Journal 6:656-663 Martin JE, Dubbert PM 1984 Behavioural management strategies for improving health and fitness. Journal of Cardiac Rehabilitation 4:200 208 May GS, Eberlein KA, Furberg CD et al 1982 Secondary prevention after myocardial infarction. A review of long-term trials. Progress in Cardiovascular Diseases 24:331 352 Mayou R, MacMahon D, Sleight P, Florencio MJ 1982 Early rehabilitation after myocardial infarction. Lancet 1: 1399-1401 Mulcahy R, Hickey N, Graham IM, MacAirt J 1977 Factors affecting the 5-year survival rate of men following acute coronary heart disease. American Heart Journal 93: 556-559 Multiple Risk Factor Intervention Trial Research Group 1982 Multiple risk factor intervention: risk factor changes and mortality results. Journal of the American Medical Association 248:1465-1477 Murray GC, Beller GH 1983 Cardiac rehabilitation following coronary artery surgery. American Heart Journal 105: 1009-1018 Nakai Y, Kataoka Y, Bando M e t al 1987 Effects of physical exercise training on cardiac function and graft patency after coronary bypass grafting. Journal of Thoracic and Cardiovascular Surgery 93:65 72 Naughton JP 1984 Contributions of exercise clinical trials to cardiac rehabilitation. Clinics in Sports Medicine 3:545 557 Nolewadika AJ, Kostuk WJ, Rechnitzer PA, Cunningham DA 1979 Exercise and human collateralisation: an angiographic and scintigraphic assessment. Circulation 60:114-120 O'Connor GT, Buring JE, Yusuf Set al 1989 An overview of randomised trials of rehabilitation with exercise after myocardial infarction. Circulation 82:234-244 O'Rourke A, Lewin B, Whitecross S, Pacey W 1990 The effects of physical exercise training and cardiac education on levels of anxiety and depression in the rehabilitation of coronary artery bypass graft patients. International Disability Studies 12: 104 106 Oberman A 1988 Rehabilitation of patients with coronary artery disease. In: Braunwald E (ed) Heart Disease: A Textbook of Cardiovascular Medicine. WB Saunders Co, Philadelphia, PA Oberman A 1989 Does cardiac rehabilitation increase long-term survival after myocardial infarction? Circulation 80:416-418 Oberman AL, Wayne JB, Kouchoukas NT, Charles ED 1982 Employment status after coronary artery bypass surgery. Circulation 65:115 119 Oldridge NB, Nagle FJ, Balke B, Cartiss RJ, Kahn DR 1978 Aorto coronary bypass surgery: effects of surgery and 32 months of physical conditioning on treadmill performance. Archives of Physical Medicine and Rehabilitation 59:268-275 Oldridge NB, Guyatt GH, Fischer ME, Rimm AA 1988 Cardiac rehabilitation after myocardial infarction. Combined experience of randomised clinical trials. Journal of the American Medical Association 260:945450 Oldridge N, Guyatt G, Jones N e t al 1991 Effects on quality of life with comprehensive rehabilitation after acute myocardial infarction. American Journal of Cardiology 67:1084-1089 Oldridge N, Furlong W, Feeny D et al 1993 Economic evaluation of cardiac rehabilitation soon after myocardial infarction. American Journal of Cardiology 72:154-161 Ornish D, Brown SE, Scherwitz LW et al 1990 Can lifestyle changes reverse coronary heart disease? The Lifestyle Heart Trial. Lancet 336:129-133

Effectiveness of cardiac rehabilitation Ott CR, Sivarajan ES, Newton KM, Almes M J, Bruce RA, Bergner M, Gilson BS 1983 A controlled randomised study of early cardiac rehabilitation: the Sickness Impact Profile as an assessment tool. Heart and Lung 12:162-170 Paffenbarger RS, Hyde RT 1984 Exercise in prevention of coronary heart disease. Preventive Medicine 13:3-22 Palatsi I 1976 Feasibility of physical training after myocardial infarction and its effect on return to work, morbidity and mortality. Acta Medica Scandinavica (Suppl) 599:1-84 Patel C, Marmot MG, Terry DJ et al 1985 Trial of relaxation in reducing coronary risk: four year follow-up. British Medical Journal 290:1103 1106 Pedersen O, Beck-Nielsen H, Heding I 1980 Increased insulin receptors after exercise in patients with insulin-dependent diabetes mellitus. New England Journal of Medicine 302: 886-892 Pell JP, Pell A C H, Morrison C, Blatchford O, Dargie H J 1996 Retrospective Study of influence of deprivation on uptake of cardiac rehabilitation. British Medical Journal 313:267-268 Picardi MH, Dennis C, Schwartz RG et al 1989 Cost-benefit analysis of early return to work after uncomplicated myocardial infarction. American Journal of Cardiology 63: 1308 1314 Ragland DR, Brand RJ 1988 Type A behaviour and mortality from coronary heart disease. New England Journal of Medicine 318:65 69 Raliegh EH, Odtohan BC 1987 The effect of a cardiac teaching program on patient rehabilitation. Heart and Lung 16: 311 317 Rarfo JA, Luksie IV, Kappagoda CT et al 1980a Effects of physical training on myocardial ischaemia in patients with coronary artery disease. British Heart Journal 43:262-269 Rarfo JA, Luksie IV, Kappagoda CT, Mary DASG, Whitaker W, Linden RJ 1980b Effects of physical training on myocardial ischaemia in patients with coronary artery disease. British Heart Journal 43:262-269 Redwood DR, Rosing DR, Epstein SE 1972 Circulatory and symptomatic effects of physical training in patients with coronary artery disease and angina pectoris. New England Journal of Medicine 286:959465 Rechnitzer PA, Cunningham DA, Andrew GA et al 1983 Relation of exercise to the recurrence rate of myocardial infarction in men: Ontario Exercise-Heart Collaborative Study. American Journal of Cardiology 51:65 69 Reid V, Graham L, Hickey N, Mulcahy R 1984 Factors affecting dietary compliance in coronary patients included in a secondary prevention programme. Human Nutrition and Applied Nutrition 38:279-287 Research Committee 1965 Low-fat diet in myocardial infarction. A controlled trial. Lancet 2:501-504 Research Committee 1968 Controlled trial of soya-bean oil in myocardial infarction. Lancet 2:693-699 Rodriguez BL, Curb JD, Burchfield CM et al 1994 Physical activity and 23 year incidence of coronary heart disease morbidity and mortality among middle aged men. The Honolulu Heart Program. Circulation 89:2540-2544 Roman O, Guitierrez M, Luksie I e t al 1983 Cardiac rehabilitation after myocardial infarction. Nine-year controlled follow-up study. Cardiology 70:223-231 Rosenberg L, Kaufman DW, Helmrich SP, Shapiro S 1985 The risk of myocardial infarction after quitting smoking in men under 55 years of age. New England Journal of Medicine 313: 1511-1517

17

Ruberman W, Weinblatt E, Goldberg JD, Chaudhary BS 1984 Psychosocial influences on mortality after myocardial infarction. New England Journal of Medicine 311:552-559 Salonen J 1980 Stopping smoking and long-term mortality after acute myocardial infarction. British Heart Journal 43: 463-469 Saons DPL 1986 Cigarette smoking: health effects and cessation strategies. Clinics in Geriatric Medicine 2:337-345 Scandinavian Simvastatin Survival Study Group 1994 Randomised trial of cholesterol lowering in 4"!,44 patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S). Lancet 344:1383-1389 Schuler G, Schlierf G, Wirth A et al 1988 Low-fat diet and regular supervised physical exercise in patients with symptomatic coronary artery disease: reduction of stress-induced myocardial ischaemia. Circulation 77:172-181 Shanfield SB 1990 Return to work after acute myocardial infarction: a review. Heart and Lung 19:109-116 Shaw LW 1981 Effects of a prescribed supervised exercise program on mortality and cardiovascular morbidity in patients after a myocardial infarction. The National Exercise and Heart Disease Project. American Journal of Cardiology 48:39-46 Shephard RJ 1983 The value of exercise in ischaemic heart disease: a cumulative analysis. Journal of Cardiac Rehabilitation 3:294-298 Siddiqui MA 1992 Cardiac rehabilitation and elderly patients. Age and Ageing 21:157-159 Siegel D, Grady D, Browner WS, Hulley SB 1988 Risk factor modification after myocardial infarction. Annals of Internal Medicine 109:213-218 Sim DN, Neil WA 1974 Investigation of the physiological basis for increased exercise threshold for angina pectoris after physical conditioning. Journal of Clinical Investigation 54: 763-770 Sivarajan ES, Newton KM, Almes MJ 1983 Limited effects of outpatient teaching and counselling after myocardial infarction. A controlled study. Lancet 2:65-73 Smith TW, Follick M J, Korr KS 1984 Anger, neuroticism, type A behaviour and the experience of angina. British Journal of Medical Psychology 57:249-252 Sparrow D, Dawber TR 1978 The influence of cigarette smoking on prognosis after a first myocardial infarction: a report from the Framingham Study. Journal of Chronic Diseases 3 h 425-432 Steele JM, Ruzicki R 1987 An evaluation of the effectiveness of cardiac teaching during hospitalisation. Heart and Lung 16: 301 311 Stern M J, Cleary P 1982 The National Exercise and Heart Disease Project: long-term psychosocial outcome. Archives of Internal Medicine 142:1093-1097 Stern M J, Gorman PA, Kaslow L 1983 The group counsel v exercise study. A controlled intervention with subjects following myocardial infarction. Archives of Internal Medicine 143:1719 1725 Sullivan M J, Higginbotham MB, Cobb FR 1988 Exercise training in patients with severe left ventricular dysfunction. Circulation 78:506-515 Tavazzi L, Boszormeny E, Broustet JP et al 1992 Cardiac surgery: background and perspectives. European Heart Journal 13 (Suppl C): 35-40 Taylor CB, Houston-Miller N, Haskell WL, DeBusk RF 1988 Smoking cessation after acute myocardial infarction. The effects of exercise training. Addictive Behaviors 13:331-335