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LEADING ARTICLE
Sports Medicine 13 (6): 365-375, 19920112-1642/92/0006-0365/$05.50/0© Adis International Limited. All rights reserved.
SP01140
Return-to-Work Evaluation after Coronary EventsSpecial Emphasis on Simulated Work Activity
Joyce Landes and Joe L. RodSanta Clara Valley Medical Center, Divisions of Cardiology and Physical Therapy,San Jose, California, USA
Interest in objective methods to facilitate returnto work after coronary events has grown in recentyears. Evidence of this interest can be observed inconferences focusing on this topic, such as theWorkshop on Occupational Cardiology (Denolin1988) co-sponsored by the World Health Organization, the 'Associazione Nazionale dei Centri perIe Malattie Cardiovascolari', Societa Italiana diMedicina del Lavoro e Igiene Industriale, and theEuropean Society of Cardiology, and the 20th Bethesda Conference (DeBusk 1988)sponsored by theAmerican College of Cardiology and co-sponsoredby the Association of Life Insurance Medical Directors of America. Few studies, however, pertaining directly to the practical methods of accomplishing return to work have been published to date. Inthis article, the usefulness, methodology, and outcomes of simulated work activity are described inthe context of epidemiological data, factors influencing return to work and methods utilised to enhance return-to-work rates.
1. Epidemiology of CoronaryArtery Disease
Despite a declining death rate due to cardiovascular disease, heart attacks claimed 513 700 livesin the United States in 1987, the most recent yearfor which statistics are available. Another 1000 000survived heart attacks that year. Currently,5 000 000 people in the US have a history of heart
attack, angina, or both. Based on the Framinghamstudy, 5% of heart attacks occur in people underage 40 and 45%occur in people under age 65. Thus,a significant part of the work force is affected bycoronary artery disease. Several studies have shownthat approximately 15 to 20% of patients who suffer a cardiac event do not return to work. Thosepatients who do return to work do so after unnecessary delays and with decreased efficiency (Cay &Walker 1988; Dennis et al. 1988). The cost due todisability payments and lost productivity is estimated at a staggering $US6.8 billion dollars in theUS for 1990 (American Heart Association 1989).The Social Security Administration reports annualdisability payments of approximately $US5.1 billion for cardiovascular disease, accounting for 30%of the total disability payments made (Guillette etal. 1988).
According to a study by Picard et al. (1989), theperformance of an Occupational Work Evaluationof low risk patients reduced the time to return towork from a mean 75 days to a mean 51 days.Projecting the cost benefit onto an estimated300 000 low risk employed survivors annually, anannual cost savings of US$800 million could berealised in the United States. Maisano and Gobbato (1988) at the Workshop on Occupational Cardiology stated that many of the patients who donot return to work could do so 'if they were rehabilitated and adequately evaluated'.
366
2. Factors Influencing Return to Work
Return-to-work rates vary significantly incountries around the world. Rates in the UnitedStates, Canada and England have been reported ashigh as 85%. On the other hand, rates in Germany,France and Switzerland rarely exceed 50% (Danchin 1988; Gehring et al. 1988). The influencingfactors are both medical and nonmedical. The literature presents conflicting opinions as to the influence of various medical factors.
Consensus of opinion considers the followingkey factors influencing re-employment: physicianadvice, patient's perceptions of health, exercise capacity, disease severity, social welfare system, financial status, age, type of occupation, length oftime absent from work, employer's attitude, emotional problems and family influence (Blumenthalet al. 1988; Davidson 1983; Guillette et al. 1988;Kavanagh & Matosevic 1988;Shanfield 1990).Kavanagh (1988) followed 1150 men with a diagnosisof myocardial infarction (MI) or coronary arterybypass graft (CABG) during 1986-87. 70.6% werewhite collar workers and 29.4% were blue collarworkers. Six months after the episode, 13.8% of bluecollar and 7.7% of white collar workers had failedto return to work. Investigation into the reasonsfor not returning to work revealed 55% admittedsocioeconomic circumstances did not encouragethem to work, 35% reported negative medical advice and 10% stated their employers' reluctance torehire them. Dennis et al. (1988) described employed low risk patients citing 'their perceptions oftheir health and the medical advice they receiveregarding re-employment' as the chief influenceson the timing of return to work.
CABG patients have demonstrated return-towork rates from 50 to 90%, which is no better thanmedically managed MI patients (Hammermeisteret al. 1979; Kinch1aet al. 1985; Russell et al. 1986;Stanton et al. 1983). A good functional capacityfollowing CABG does not necessarily predict postoperative employment. The major predictors ofreturning to work after successful CABG arenonmedical, and include the length of preoperativeunemployment and the nature of physician advice
Sports Medicine 13 (6) 1992
(Cay & Walker 1988; Davidson 1983; Stanton etal. 1983; Walter 1988). Efforts aimed at reducingpreoperative unemployment times and ensuringconsistent, specific and positive physician adviceshould, therefore, increase the rate of return to workfor CABG patients.
3. Return-to- Work Evaluation
Frequently, a patient's physician is requested tocertify the ability to resume work - either the previous position, a modification of the previous position or entirely new work. Physician recommendations are often based on subjective opinions(Dennis 1988). Inaccurate determination frequently results in either delays in re-employmentor persistent disability. The costs of such an errorare socioeconomic, and affect the individual's family and personal self-worth (Sheldahl 1985).
Task Force I at the 20th Bethesda Conferencerecommended consideration of 3 aspects in evaluating return to work: (a) the capability of the individual to perform the job; (b) the risk to the individual of performing the job; and (c) the risk tosociety if the individual is performing the job (Pryoret al. 1988). In evaluating patient capability andjob risk, an analysis of both the characteristics ofthe job and the patient's physical capacity must bemade.
Important job characteristics include the type ofphysical work (i.e. static or static-dynamic), the energy requirements, environmental stressors andpsychological stressors (Haskell et al. 1988; Sheldahl 1985). Occupational medicine physicians canbe especially helpful in providing objective job analysis information.
Evaluating patients for return to jobs which maypose a risk to public safety is especially difficultbut accuracyis essential.On-the-job conditions suchas those confronted by firefighters are difficult toreplicate in the laboratory setting. The goal, however, is to estimate the probability of an individualexperiencing a coronary event on the job when itwould otherwise be unlikely (Haskell et al. 1988).
The initial occupational assessment should begin as soon as the patient is clinically stable. The
Return-to-Work Evaluation afterCoronary Events
20th Bethesda Conference recommended testing at5 weeks for an uncomplicated MI, 7 weeks afterCABG, and 1 week after coronary angioplasty(Haskell et al. 1988).
3.1 Physiological Response to OccupationalWork Demands
Occupational work is a combination of static orisometric and dynamic work. The relative contribution of each is dependent upon the type of taskperformed. Sheldahl et al. (1985) state that the energy cost of specific jobs is influenced by the rateof work, efficiency and size of worker, orthopaedicdisability, and degree of automation available onthe-job. Work related factors such as temperaturestress, psychological stress, awkward body positions .and static work can significantly increasemyocardial oxygen demand. The haemodynamicresponse to work varies according to the presenceof the different work-related factors.
Static work generally results in higher systolicand diastolic blood pressures, but lower heart rateand rate pressure product than dynamic work. Theanginal threshold, identified by maximum ratepressure product (RPP) achieved on a symptomlimited graded exercise test (SLGXT), is reproducible for similar dynamic workloads in the workplace. When a large static component is added tothe dynamic work, however, the anginal threshold,represented by RPP, shifts upward. Thus an individual can sustain a higher workload doing isometric and/or isodynamic work than dynamic workbefore evidence of myocardial ischaemia is noted(DeBusk 1978).
For patients with severely decreased left ventricular function (class III or IV NYHA) who donot possess a normal cardiac reserve, a sudden increase in blood pressure and, hence, sudden increase in myocardial oxygen demand secondary tostatic exercise can result in dire consequences.Graves et al. (1988), in a study comparing themetabolic and haemodynamic responses to submaximal exercises in 12 hypertensive responders,found a great variation in systolic blood pressureresponse to static work involving carrying hand-
367
held weights. He recommended 'careful observation of blood pressure response to exercise withhand-weights ... before prescribing hand-weightexercise where increased cardiac afterload is contraindicated'.
Sheldahl et al. (1983) assessed the cardiovascular responses of 52 patients ~ 2 months after MIto carrying graded weight loads of 20 to 50lb (9 to23kg) while walking on the treadmill at a comfortable speed. One-third of the patients reached adiastolic blood pressure of 120mm Hg, an end-pointto their test protocol. The diastolic blood pressureresponse to static exercise was significantly greaterthan that achieved during dynamic exercise. Thesafety of increasing diastolic blood pressure togreater than or equal to 120mm Hg repeatedlyeither in a work day or in doing activities of dailyliving has not been established in patients with previous MI (Sheldahl et al. 1983). Saito et al. (1987)also found that continuous activity increased bloodpressure to a greater extent than intermittent activity. This further suggests the need to establishappropriate blood pressure end-points which canbe safely generalised to the job.
Borg's rating of perceived exertion (RPE) scale(1982) is frequently used as a method for patientsto subjectivelymonitor their own safeactivity level.In our study of the safety and clinical applicabilityof a specific simulated work activity protocol, RPEat a safe prescribed training threshold based onSLGXT correlated with different haemodynamicresponses to the same perceived threshold of workin simulated work activity (Rod et al. 1989).Thus,we recommend determining haemodynamic responses in cardiac patients engaging in weightcarrying or weight-lifting activities for specific exercise prescription, treating hypertensive responsesas necessary.
3.2 Graded Exercise Test
A multitude of articles and texts have documented the many benefits of the graded exercisetest (Cohn 1988; DeBusk et al. 1986; Schlant et al.1986; Ellestadt 1986; Rabbani & Antman 1989;Weiner et al. 1984). In 1980, DeBusk and David-
368
son reported the use of treadmill exercise testing 3weeks following an uncomplicated MI to determine the occupational work potential of 196 menaged 70 or less. They found it to be very useful instratifying low from high risk patients, enabling lowrisk patients an early return to employment andguiding future medical direction of the high riskpatient. Rod et al. (1982) reported similar findingsin patients following cardiovascular revascularisation procedures.
The primary purposes of the GXT are to determine the functional capacity and to identify anyabnormal responses to exercise. The results shouldbe evaluated in the framework of the job requirements. According to Task Force II of the 20th Bethesda Conference (Haskell et al. 1988), an individual should be able to exercise 'free of significantcardiac dysfunction that is at least twice the average energy requirement and 20% more than theexpected peak energy requirement on the job'.
Poor performance in the initial GXT does notpreclude eventual employment. Further medical orsurgical intervention may be indicated. Referral toa cardiac rehabilitation programme may facilitateimproved functional capacity and modification oflifestyle as appropriate. After a determinate rehabilitation programme, the patient should be reevaluated for return to work.
3.3 Simulated Work Activity
The graded exercise test does not take into account the effect of the work, weight-carrying,weight-lifting, working in body positions other thanupright, and working in the presence of environmental or psychological stressors. In occupationsaffected by the aforementioned factors, return-towork recommendations should not be made basedexclusively on GXT outcomes. Haskell et al. (1988)at the 20th Bethesda Conference recommended labwork simulation or on-site monitoring 'may benecessary for occupations posing unusually taxingphysical, psychological or environmental stress, especially those posing a risk to the public'.
Many patients can benefit from a simulatedwork activity (SWA) test. Patients who perform well
Sports Medicine 13 (6) 1992
on SLGXT and are stratified into the low risk group(> 7 METs) but who are returning to work with alarge static component should have an SWA testto evaluate their blood pressure response to staticand isodynamic work. Patients hypertensive at restor in response to dynamic exercise should also beassessed performing static activities. For mediumto high risk patients returning to selected job tasksor leisure activities, SWA provides more accurateassessment than the SLGXT of a patient's abilityto safely resume such workloads. Patients whoseSLGXT is borderline for recommending return toemployment at a given workload can frequentlybenefit from SWA (Haskell et al. 1988; Kavanagh& Matosevic 1988; Rod et al. 1989; Sheldahl 1985).These patients may actually respond adequately tostatic workloads, which are more relevant to thework place, then to dynamic work. For patients unable to do a dynamic exercise test or whose GXTend-point is limited by a noncardiac reason but whoare returning to heavy manual labor, SWA can assess their cardiovascular response to static and isodynamic work.
The results of SWA may reassure anxious employers, patients, and families of the safety of returning to work. Specific guidelines regarding theamount of weight a patient can lift or carry on-thejob can also be given. Two of the most significantfactors influencing return to work - physician advice and patient's perception of health - are bothpositively influenced by the completion of SWAtests. Patients and families are tested in an atmosphere conducive to receiving instruction about energy conservation, proper body mechanics, and application ofobjective test results to activities outsideof the clinical lab. An added advantage of SWA isthe ability to standardise procedures, the provisionof quantifiable results, and the ready availabilityof trained emergency personnel and equipment(Haskell et al. 1988; Kavanagh & Matosevic 1988;Rod et al. 1989; Sheldahl et al. 1985).
3.4 On-Site Testing
Some occupations m!1y not be capable of beingadequately reproduced in a clinical lab to evaluatefunctional capacity via SWA. In occupations with
Return-to-Work Evaluation after Coronary Events
environmental stress factors, such as temperatureextremes, humidity, altitude or the wearing ofheavy, confining clothing, on-site testing may benecessary. In occupations with significant psychologicalstress eliciting emotional factors such as fear,anxiety, and/or excitement, on-the-job analysis isalso necessary. Examples of such jobs are policemen, firefighters, and air traffic controllers; theseoccupations are also public risk jobs where the needfor accurate assessment is essential to protect thepublic's safety.
On-site testing requires taking portable telemetry to the workplace to monitor ECG in combination with the haemodynamic response to aworker's daily routine. Kavanagh (1988), in describing on-site testing as done at the Toronto Rehabilitation Centre, recommends a physician andtherapist or technician perform the evaluation together.
On-site testing has the benefit of being the mostaccurate assessment method attainable when donewith the proper equipment and by the appropriatepersonnel. Disadvantages include the cost, the testing and travel time, the need for specialised equipment and the need for specially trained personnel.The disadvantages of on-site testing may often appear prohibitive, but the benefit to the individualand community in returning patients to work whomay otherwise resort to long term disability makeson-site testing worthwhile.
4. Simulated Work Activity Guidelinesand Protocols
Recent studies have evaluated the usefulnessandhaemodynamic responses of varying combinationsof static and dynamic work. Different methodologies have been described by different investigators to date. Standardised protocols to be used bymultiple clinicians have not yet been established.
4.1 Studies
Sheldahl et al. (1985) have developed tests thatsimulate different types of work requirements andmay be administered following an initial SLGXT
369
4 to 8 weeks after MI or CABG. Specific SWA testsare selected based on an analysis of a patient's realjob requirements.
Patients whose jobs entail sustained staticdynamic work receive a weight-carrying test (WCT).Patients carry weight loads of 20, 30, 40 and 50lb(9, 14, 18 and 23kg), while ambulating on a treadmill at approximately 2mph (3.2 km/h). Eachweight is carried for 2 minutes followed by a 2- to3-minute rest period. The 50lb limit was determined because the authors state 'this represents thepeak weight-carrying load expected of most individuals in occupational settings'. ECG is continuously monitored. Blood pressure and heart rate aremeasured at the end of each minute. The end-pointsof the protocol included fatigue, SBP ~ 250mm Hg,DBP ~ 120mm Hg, exercise-induced hypotension,limiting angina, ST depression ~ 3mm and ventricular tachycardia ~ 3 consecutive PYCs. A studyof 52 post-MI patients, based on this protocol,showed 38% completed the entire protocol. Theend-points for incomplete tests were DBP ~ 120mmHg in 16, arm fatigue in 12, and arrhythmia andangina in I each. Patients showed a higher meanrise in SBP and DBP, but lesser mean rise in heartrate and RPP, in the weight-carrying test than inthe SLGXT.
A second test described by the authors was repetitive weight-lifting (WLT) used to evaluate workdone in occupations such as farming, warehousing,truck driving, and masonry. The test was dividedinto four 6-minute work stages with 2-minute restintervals between stages. Each patient was instructed to set a pace of lifting which he or she feltcould be sustained for 30 minutes. In stage I, thepatient moved a 30lb (14kg) weight repeatedly between the floor and a 33-inch (84cm) high table.In stages 2, 3 and 4, 40lb (18kg), 50lb (23kg) and40lb weights, respectively, were moved accordingto the stage I protocol. ECG was continuouslymonitored. Blood pressure was measured while thepatient held the weights momentarily at the end ofthe second and sixth minutes of each stage. Endpoints were identical to the weight-carrying test.Blood pressure responses fluctuated widely duringlifting and releasing weights. The mean haemo-
370
dynamic response was intermediate to the WCTand the SLGXT.
Sheldahl et al. (1985) report that either of theabove protocols can be modified to match the jobspecifications. Other SWA tests may utilise weightlifting equipment, arm ergometry, heat or coldstressors, and the use of questionnaires to screenfor psychological stress.
Rod et al.(1989) had a dual purpose to theirstudy of a clinical protocol for SWA. First was theassessment of its applicability in a clinical settingfor patients after cardiac events in order to facilitate safe return to heavy physical work. The secondobjective was to evaluate the validity of RPE as aparameter for exercise prescription in SWA.
15 patients from 2 to 21 months after MI, PTCA,and/or CABG underwent SWA after performing at~7 METs on an SLGXT. All patients performed aWCT and a WLT adapted from the protocol ofSheldahl et al. (1985). Table I presents the criticalelements of the test procedure.
The test results demonstrated the safety andusefulness of the test. Ten of the 15 patients perceived the test as being very helpful and havingrestored their confidence in returning to manuallabour. We established 95mm Hg as the upper acceptable diastolic blood pressure limit for return to
Sports Medicine 13 (6) 1992
the work force. Five patients exceeded this limit.Three patients stopped the WCT before completing the test protocol, because of their hypertensiveresponse. Recommendations regarding changes inmedication were influenced by both the simulatedwork activity stage at which the hypertensive resultoccurred compared with the estimated workloadneeded on the job, and the magnitude of the hypertensive response.
The workload for a given RPE on the SLGXTwas not applicable to the SWA workload. SimilarRPEs on the SWA tests resulted in significantlydifferent haemodynamic responses than were elicited on the SLGXT. Especially noteworthy, theDBP of 92 ± 8mm Hg in the WCT was significantly higher than the 81 ± 11mm Hg observedin the SLGXT. The SWA protocol employed inthis study appears safe and feasible to implementin the clinical setting.
Dafoe et al. (1990) presented a case report demonstrating the presence of arrhythmias during SWAtests of weight-lifting and weight-carrying whichwere not seen on the preceding standard SLGXT.In addition, these arrhythmias occurred at a lowerRPP with WCT and WLT than SLGXT. A preliminary job analysis revealed the patient needed tolift and carry 100lb (45kg) weights at a peak work-
Table I. Clinical simulated work activity protocol by Rod and colleagues. (a) A baseline GXT is first performed utilising the clinician'spreferred test' protocol. (b) Two SWA tests are conducted
Stages
Weight-carrying test (WeT)
4 stages; 3-minute duration each;
3-minute rest intervals
Weight-lifting test (WLT)
3 stages; 4-minute duration each; 3minute rest intervals
Activity
Treadmill at 0% grade. 1.52.0 mph (2.4-3.2 krn/h):
carrying graduated weights
I 20lb (9kg)II 30lb (14kg)III 40lb (18kg)
IV 50lb (23kg)
Lift weights between floorand gurney or table 3-6times per minute
130lb
1140lb
III 50lb
Monitoring
Continuous 12-lead ECG HR.RPE each minute
BP at end of each stage.
Signs and symptoms
Continuous 12-lead ECG HR.RPE each minute.
BP at 2 and 4 minutes in
each stage
Signs and symptoms
Test end-points
According to American
College of Sports Medicine
(ACSM) except DBP >95mm Hg and/or testworkload equals that inworkplace
According to ACSM exceptDBP > 95mm Hg and/or testworkload equals that in
workplace
Return-to-Work Evaluation afterCoronary Events
load of 9 METs. Speed, accuracy, and productionpressure were characteristics of the job. A weightlifting and carrying protocol was devised to simulate the patient's job requirements. A dynamic exercise test indicated the patient's maximum workload achieved was 12 METs with a maximum RPPof 331 x 102 and the presence of no ST changesor arrhythmias. The SWA, however, resulted inruns of ventricular bigeminy at RPP of 204 x 102
after 80 seconds of lifting a 100lb weight. TheSLGXT would have cleared the patient to returnto work, but the SWA indicated the patient wasnot safe to return to his previous position. Afterrepeated testing, in fact, the patient was advised tolimit his lifting to 20lb.
Kavanagh and Matosevic (1988)described at theWorkshop on Occupational Cardiology (1988) themultifaceted approach to work assessment of thecardiac patient utilised at the Toronto Rehabilitation Centre. An individualised assessment is provided which includes all or part of the followingsteps: obtain a job description, determine any applicable trade or legal restrictions, investigate psychological status, perform a graded exercise test, atelemetered job simulation in the RehabilitationCentre, and an on-site assessment.
Job simulation in the facility consists of the performance of tasks similar to those patients encounter in their occupations under the auspices oftherapists in either the Occupational Therapy orPre-Vocational Departments. Patients performtasks such as carpentry or house painting whilebeing continuously monitored for ECG, bloodpressure and signs and symptoms abnormalities.Patients may also be assigned to work in Centredepartments, for example, cafeteria, boiler room,external grounds, which are similar to their ownemployment setting. Monitoring proceeds the sameas if the patients simulated the activity in thetherapy areas. At times, the assessment may extendbeyond 1 day. In that case, monitoring may be acombination of Holter and work station monitoring. For moderate to high risk patients, work assessments by this facility's system are possible inan environment conducive to maximising patient
371
safety by the ready availability of trained personneland emergency equipment.
Wermuth et al. (1990) conducted a study to determine if dynamic arm exercise tests or leg exercise tests were more accurate predictors of thehaemodynamic response to simulated work activity for 9 patients who had sustained MI. The simulated tests consisted of weight-carrying, repetitiveweight-liftingand overhead isodynamic work. Armexercise testing proved to be a more accurate predictor of a patient's cardiovascular response tosimulated work tasks. As a result of the outcomeof this pilot study, the authors recommend completion of both leg and arm ergometry tests.
4.2 Ergonomic Equipment
Sophisticated, computerised equipment has become the keystone for systems of functional capacity testing advocated by various companies.Several physical tasks can often be simulated on asingle piece of equipment. The tests can be standardised and provide objective information as tothe work capacity of a patient. Functional capacitytesting has been widely employed in the assessment of injured workers, especially those with orthopaedic diagnoses. These same methods can alsobe applied to the cardiac patient given the inclusion of appropriate monitoring techniques into theassessment process. Continuous ECG monitoringand signs and symptoms monitoring as well as periodic heart rate and blood pressure measurementsprovide the tester with the necessary cardiac information on which to base return to work recommendations.
5. Cardiac Rehabilitation
Patients who do not achieve an exercise test orsimulated work activity workload capacity comparable to their real occupational requirements mayoften benefit from participation in an outpatientcardiac rehabilitation programme. Aerobic conditioning and strength training in a supervised setting frequently improves a patient's physical capacity to return to manual labour. In addition, the
372
patient receives information on proper body mechanics, proper breathing techniques and self-pacing to improve the efficiency ofcardiovascular performance (Fletcher et al. 1990; Greenland & Chu1988; Nakai et al. 1987; Parmley 1986).
5.1 Circuit Weight-Training
Stewart et al. (1988) define circuit weight-training as 'the performance of a series of weight-liftingexercises designed to improve muscular strengthand cardiovascular endurance. Strength improvement results from progressive resistance training.Cardiovascular endurance improves through thecontinuous activity of performing the resistive exercise and moving quickly from one exercise to another.' Some programmes have a dynamic component consisting of leg ergometry utilisingtreadmill and cycle work in conjunction with astatic component of resistance exercises (Kelemenet al. 1986). An effective exercise prescription canbe based upon the outcome of the simulated workactivity test with the goal of achieving the necessary workload to safely return to work or to desiredleisure-time activities.
Until recently, weight-lifting was considered unsafe for cardiac patients due to the risk of imposinga sudden increase in myocardial workload whichbeing uncompensated would result in myocardialischaemia (McCool & Nelson 1985). In selectedgroups of cardiac patients, circuit training has beenproven safe. Haslam et al. (1988) assessed theelectrocardiographic and blood pressure responsesto upper and lower extremity static exercise. Bloodpressure was measured by invasive monitoring ofthe brachial artery to insure accuracy. They concluded in the group of patients studied that weightlifting exercises resulted in clinically acceptableblood pressure and electrocardiographic responses.Another recent study compared and contrasted thecardiovascular response to aerobic versus circuittraining programmes in 13 men with known coronary artery disease. In addition to the traditionalmonitoring procedures of ECG, HR, BP and signsand symptoms, 2-dimensional echocardiographywas used to detect exercise-induced ischaemic left
Sports Medicine 13 (6) 1992
ventricular wall motion abnormalities. Thehaemodynamic response to resistance exercise wasappropriate including consistently adequate leftventricular perfusion.
Other studies attest to not only the safety of circuit training but also the benefit of increasing aerobic endurance, musculoskeletal strength, bodycomposition and self-efficacy in performing armtasks (Kelemen et al. 1986; Gettman & Pollock1981; Stewart et al. 1988). In a study of 25 patientswith coronary artery disease participating in a 3year programme of circuit training, those patientsenrolled in the weight-training group had a 16%gain in self-efficacy. This is in contrast to the control group enrolled in dynamic exercise only whichexperienced an II % decline in self-efficacy (Stewart et al. 1988). Given that patients' perception oftheir health status is very influential in returningthem to work, a gain in self-confidence regardingarm tasks should have a positive influence on return-to-work rates.
Entry criteria for circuit weight-training programmes have not been uniformly established.Conservative recommendations by the AmericanAssociation of Cardiovascular and Pulmonary Rehabilitation, an organisation representing cardiopulmonary rehabilitation professionals, call for theinclusion oflow-risk cardiac patients and high-riskadults (AACVPR 1991). The American College ofSports Medicine (ACSM 1991) states in selectpatients low level resistance exercise may be startedas early as 7 to 8 weeks so long as an SLGXT hasalready been performed. In addition, the ratio ofwork to rest period and the appropriate determination of exercise weights is also based on empirical knowledge. One study recommends usingstandard levels of exercise resistance (40 to 60% ofthe l-repetition maximum) with 60-second restcycles between stations to allow for more completerecovery of HR and BP (Butler et al. 1987). Another study utilised 30-second rest periods betweenstations (Kelemen et al. 1986). Definitive recommendations regarding programme parameters arenot yet available. Suggestions for implementing resistance training are outlined in manuals publishedby the ACSM (1991) and the AACVPR (1991).
Return-to-Work Evaluation after Coronary Events
6. Recommendations
It is well established that all cardiac patients ableto achieve 2.0 METs during cardiac rehabilitationshould undergo graded exercise testing. Importantinformation regarding prognosis, functional capacity, arrhythmia detection and efficacy of therapyare obtained. Information gleaned during the gradedexercise test also guides recommendations for return to work or leisure-time activities. In low riskpatients returning to a sedentary job or lifestyle,the graded exercise test may be all that is necessaryto make appropriate recommendations. In manyother circumstances, for example, for low riskpatients returning to heavy work or for moderateto high risk patients, the graded exercise test maybe only the first of many tests necessary to makeaccurate recommendations when the ability to perform static or isodynamic work is in question.
Simulated work activity testing provides a safe,efficient, and practical approach to making objective recommendations for a patient's return to specific vocational or avocational pursuits. We havereported a clinical model for safe application byexercise test facilities incorporating a weight-carrying and a weight-lifting protocol with conservative end-points (Rod et al. 1989). The controlledstudy of simulated work activity testing is in itsincipience. Further investigation is needed in several areas related to simulated work activity: prospective monitoring of SWA testing's impact onreturn-to-work rates, impact on psychosocial characteristics, validity testing by comparing a patient'sperformance in the workplace to that noted duringSWA, inclusion of other parameters such as environmental stressors or body position into the testmodel, refinement of indications and criteria forparticipation in SWA testing, determination of appropriate systolic and diastolic blood pressure endpoints generalisable to an 8-hour work schedule,the reliability of RPE as a self-assessment tool during heavy physical work, and the necessary frequency of repeat SWA testing.
In cases which are difficult to simulate in thelab or for which a high degree of accuracy is essential, other test options may need to be incor-
373
porated. The use of computerised, ergonomicequipment and on-site testing have been describedabove.
When test results suggest a patient is not safeor capable of resuming her or his premorbid workstatus, a trial of cardiac rehabilitation may oftenrestore cardiovascular function as necessary. Theinclusion of circuit weight-training into a cardiacrehabilitation programme is also relatively new. TheSWA test may be utilised to set exercise trainingintensity when static work is to be performed. Preliminary studies have demonstrated the safety andeffectiveness of circuit-weight training for cardiacpatients.
7. Conclusions
Until recently, the outcome of medical management of patients sustaining cardiac events wasmeasured primarily in terms of mortality statistics.In the past decade, increased attention has beenfocused on the quality of life and socioeconomicfactors for the postcoronary event patient. Progresshas been made in reducing the unnecessary number of cardiac patients electing to be supported bylong term disability and in reducing delays in return-to-work. A meaningful strategy for return-towork evaluations has evolved. The following seriesof steps has demonstrated success in achieving improvement in return-to-work statistics: job analysis, graded exercise test, psychological screen withappropriate referral when indicated, simulated workactivity test, physician advice, referral to cardiacrehabilitation if necessary, reinforcement by follow-up clinic visits, repeat testing for changes insymptoms and/or work status, and monitoring viaannual graded exercise test and simulated work activity. It is incumbent upon physicians specialisingin the care of the cardiac patients to apply this newbody of knowledge in their clinical practice. Greatbenefit will be realised by cardiac patients, theirfamilies and society.
References
American Association of Cardiovascular and Pulmonary Rehabilitation. Guidelines for cardiac rehabilitation programs, Human Kinetics Books, Champaign, III., 1991
374
American College of Sports Medicine. Guidelines for exercisetesting and prescription, 4th ed., Lea and Febiger, Philadelphia, 1991
American Heart Association. 1990 Heart and Stroke Facts, American Heart Association, Dallas, 1989
Blumenthal JA, Bradley W, Dimsdale JE, Kasl SV, Powell LH,et al. Task force III: Assessment of psychological status inpatients with ischemic heart disease. Journal of the AmericanCollege of Cardiology 14: 1034-1042, 1989
Borg GAV. Psychophysical bases of perceived exertion. Medicineand Science in Sports and Exercise 14: 377-381, 1982
Butler RM, Beierwaltes WH, Rogers FJ. The cardiovascular response to circuit weight training patients with cardiac disease.Journal of Cardiopulmonary Rehabilitation 7: 402-409, 1987
Cay EL, Walker DD. Psychological factors and return to work.European Heart Journal 9 (Suppl. L): 74-81, 1988
Cohn PF. Silent myocardial ischemia. Annals of Internal Medicine 109: 312-317, 1988
Dafoe WA, Cupper L, Tan KW. Case report: A vocational assessment that required a weight lifting and carrying test. Journal of Cardiopulmonary Rehabilitation 10: 126-129, 1990
Danchin N. Work capacity after myocardial revascularization:factors related to work resumption. European Heart Journal 9(Suppl. L): 44-47, 1988
Davidson DM. Return to work after cardiac events: a review.Journal of Cardiac Rehabilitation 3: 60-69, 1983
DeBusk RF. 20th Bethesda Conference: Insurability and Employability of the Patient with Ischemic Heart Disease: introduction. Journal of the American College of Cardiology 14:1008-1009, 1989
DeBusck RF, Blomqvist CG, Kouchoukos NT, et al. Identification and treatment of low-risk patients after acute myocardialinfarction and coronary artery bypass surgery. New EnglandJournal of Medicine 314: 161, 1986
DeBusk RF, Davidson DM. The work evaluation of the cardiacpatient. Journal of Occupational Medicine 22: 715-721, 1980
DeBusk RF, Valdez R, Houston N, Haskell W. Cardiovascularresponses to dynamic and static effort soon after myocardialinfarction: application to occupational work assessment. Circulation 58: 368-375, 1978
Dennis C, Houston-Miller N, Schwartz RG, Ahn DK, KraemerHC, et al. Early return to work after uncomplicated myocardialinfarction: results of a randomized trial. Journal of the American Medical Association 260: 214-220, 1988
Denolin H, Feruglio GA, Gobbato F, Maisano G. Guidelines forreturn to work after myocardial infarction and/or revascularization. European Heart Journal 9 (Suppl. L): 130-131, 1988
Ellestad MH. Stress testing: principles and practice, 3rd ed. FADavis, Philadelphia, 1986
Fletcher GF, Froelicher VF, Harley LH, Haskell WL, Pollock ML.Exercise standards: a statement for health professionals fromthe American Heart Association. Circulation 82: 2286-2322,1990
Gehring J, Koenig W, Rana NW, Mathes P. The influence ofthetype of occupation on return to work after myocardial infarction, coronary angioplasty and coronary bypass surgery. European Heart Journal 9 (Suppl, L): 109-114, 1988
Gettman LR, Pollock ML. Circuit weight training: a critical review of its physiological benefits. Physician and Sportsmedicine 9: 44-60, 1981
Graves JE, Sagiv M, Pollock ML, Miltenberger LA, Effect of handheld weights and wrist weights on the metabolic and hemodynamic responses to submaximal exercise in hypertensive responders. Journal of Cardiopulmonary Rehabilitation 8: 134140, 1988
Greenland P, Chu JS. Efficacy of cardiac rehabilitation services:With emphasis on patients after myocardial infarction. Annalsof Internal Medicine 109: 650-663, 1988
Guillette W, Judge RD, Koehn E, Miller JE, Miller RK, et al.
Sports Medicine 13 (6) 1992
Committee report on economic, administrative and legal factors influencing the insurability and employability of patientswith ischemic heart disease. Journal of the American Collegeof Cardiology 14: 10I0-1015, 1989
Hammermeister KE, De Rouen TA, English MT, Dodge HT. Effect of surgical versus medical therapy on return to work inpatients with coronary artery disease. American Journal ofCardiology 44: 105-111, 1979
Haskell WL, Brachfeld N, Bruce RA, Davis PO, Dennis CA, etal. Task force II: determination of occupational working capacity in patients with ischemic heart disease. Journal of theAmerican College of Cardiology 14: 1025-1034, 1989
Haslam. DRS, McCartney N, McKelvie RS, MacDougall JD. Direct measurements of arterial blood pressure during formalweightlifting in cardiac patients. Journal of CardiopulmonaryRehabilitation 8: 213-225, 1988
Kavanagh T, Matosevic V. Assessment of work capacity in patientswith ischaemic heart disease: methods and practices. EuropeanHeart Journal 9'Suppl. L): 67-73, 1988
Kelemen MH, Steward KJ, Gillilan RE, Ewart CK; Valenti SA,et al. Circuit weight training in cardiac patients. Journal of theAmerican College of Cardiology 7: 38-42, 1986
Kinchla J, Weiss T. Psychologic and social outcomes followingcoronary artery bypass surgery. Journal of CardiopulmonaryRehabilitation 5: 274-283, 1985
McCool K, Nelson KM. A practice of cardiac rehabilitation. Cardiology Clinics 3: 269-280, 1985
Nakai Y, Kataoka Y, Bando M, Hiasa Y, Taki H, et al. Effectsof physical exercise training on cardiac function and graft patency after coronary artery bypass grafting. Journal of Thoracicand Cardiovascular Surgery 93: 65-72, 1987
Parmley WW. President's page: Position report on cardiac rehabilitation. Journal of the American College of Cardiology 7:451-453, 1986
Picard MD, Dennis C, Schwartz RG, Ahn DK, Kraemer HC, etal. Cost-benefit analysis of early return to work after uncomplicated acute myocardial infarction. American Journal of Cardiology 63: 1308-1314, 1989
Pryor DB, Bruce RA, Chaitman BR, Fisher L, Gajewski J, et al.Task force I: Determination of prognosis in patients with ischemic heart disease. Journal of the American College of Cardiology 14: 1016-1025, 1989
Rabbani LE, Antman EM. Exercise testing and ambulatory monitoring: I. Exercise testing methods and applications. Cardiovascular Reviews and Reports 10: 46-53, 1989
Rod JL, Braun JQ, Rehm LM, Landes JR. Simulated work activity in patients with coronary artery disease: a clinical protocol. Journal of Cardiopulmonary Rehabilitation 9: 439-444,1989
Rod JL, Squires RW, Pollock ML, Foster C, Schmidt DH. Symptom-limited graded exercise testing soon after myocardial revascularization surgery. Journal of Cardiac Rehabilitation 2:199-205, 1982
Russel RO, Abi-Mansour P, Wenger NK. Return to work aftercoronary artery bypass surgery and percutaneous transluminalangioplasty: issues and potential solutions. Cardiology 73: 306322, 1986
Saito M, Yamazaki T, Goto Y, Sumiyoshi T, Fukami K, et al.Cardiovascular responses during ordinary activities in healthysubjects: predominance of blood pressure response over heartrate in activities with isometric components. Journal of Cardiopulmonary Rehabilitation 7: 253-258, 1987
Schlant RC, Blomqvist CG, Brandenburg RO, DeBusk R. Ellestad MH, et al. Guidelines for exercise testing: a report of theAmerican College of Cardiology/American Heart AssociationTask Force on Assessment of Cardiovascular Procedures (Subcommittee on Exercise Testing). Journal of the American College of Cardiology 8: 725-738, 1986
Return-to-Work Evaluation after Coronary Events
Shanfield SB. Return to work after an acute myocardial infarction: a review. Heart and Lung 19: 109-117, 1990
Sheldahl LM, Wilke NA, Tristani FE. Exercise prescription forreturn to work. Journal of Cardiopulmonary Rehabilitation 5:567-575, 1985
Sheldahl LM, Wilke NA, Tristani FE, Kalbfleisch JH. Responseof patients after myocardial infarction to carrying a graded series of weight loads. American Journal of Cardiology 52: 698703, 1983
Sheldahl LM, Wilke NA, Tristani FE, Kalbfleisch JH. Responseto repetitive static-dynamic exercise in patients with coronaryartery disease. Journal of Cardiac Rehabilitation 5: 139-145,1985
Stanton BA, Jenkins CD, Denlinger P, Savageu JA, WeintraubRM, et al. Prediction of employment status after cardiac surgery. Journal of the American Medical Association 249: 907911, 1983
Stewart KJ, Mason M, Kelemen MH. Three-year participation in
375
circuit weight training improves muscular strength and selfefficacy in cardiac patients. Journal of Cardiopulmonary Rehabilitation 8: 292-296, 1988
Walter PJ. Return to work after coronary artery bypass surgery.European Heart Journal 9 (Suppl, L): 58-66, 1988
Weiner DA, Ryan TJ, McCabe CH, et al. Prognostic importanceof a clinical profile and exercise test in medically treated patientswith coronary artery disease. Journal of the American Collegeof Cardiology 3: 772-779, 1984
Wermuth E, Olund C, Pease MO, Hanson P. A comparison ofarm and leg exercise testing to predict cardiovascular responsesto simulated work tasks in stable cardiac patients. Journal ofCardiopulmonary Rehabilitation 10: 317-322,1990
Correspondence and reprints: Joyce Landes. Santa Clara ValleyMedical Center, 751 South Bascom Avenue, San Jose, CA 95128,USA.
The Process of Training and Competitionin View of the Performances at the
1992 Barcelona Games
Date: 4-6Venue:
ovember, 1992etanya, Israel
For further information. please contact:
Hony TenenbaumInternational Congre
Wingate Institute for Physical Education and portWingate Po t Office
etanya, 42902I RAEL