Cardiac Rehabilitation

Author(s): Maricarmen Cruz, MD, Isabel Borras, MD, Jose Cumba, MD

Originally published:12/09/2011

Last updated:04/21/2016

1. DISEASE/DISORDER:

Definition

The purpose of cardiac rehabilitation is to restore and improve function, limit disability, minimize cardiac risk factors, and optimize cardiac conditioning through a prescribed and supervised exercise program that includes life style modification, education and counseling. The goal is to optimize physical, psychological and social functioning that allows resumption of normal daily activities without significant cardiac symptoms.1

Etiology

Coronary atherosclerosis results from plaque formation in the vessels of the heart. Congestive heart failure is due to other causes, including ischemic injury, hypertensive injury, arrhythmia, and toxic and metabolic effects. Ischemic heart disease is due to the prevalence of obesity, inactive lifestyle, and smoking. Cardiovascular disease is the leading cause of death and disability in the United States.

Epidemiology including risk factors and primary prevention

Coronary artery disease (CAD) is the foremost cause of mortality in the United States. In 2013 the death rate from CAD was 193.3 per 100,000, accounting for 24% of all deaths in the USA. Coronary heart disease (CHD) is the most common type of heart disease, accounting for over 370,000 people annually in the US.2

Irreversible risk factors for developing cardiac disease include: age, male gender, history of vascular disease, and family history. Reversible risks include “metabolic syndrome,” with diabetes, hypertension, hypercholesterolemia, abdominal obesity, smoking, activity, stress, Type A personality, and diet.3

Cardiac rehabilitation impacts the risk factors associated to coronary artery disease by using a comprehensive approach that incorporates life style changes.  Standard outpatient cardiac rehabilitation lasting 6-12 weeks and have shown to improve physical function in patients with CAD by up to 15%.4

Patho-anatomy/Physiology

The heart is a major component of the cardiovascular system. It pumps oxygenated blood to the systemic circulation. Cardiac disease entails either pump failure or ischemia to the cardiac muscle. Valvular heart disease decreases maximum cardiac output (CO), resulting in increased myocardial oxygen consumption (MVO2) and decreased maximal oxygen consumption (VO2 max), along with increased oxygen consumption during submaximal exercise. Myocardial infarction decreases ejection fraction, thereby reducing stroke volume and CO, while ischemic heart disease results in a lower maximal heart rate, resulting in lower VO2 max. Congestive heart failure results in decreased cardiac output with low stroke volume, which is associated with a lower VO2 max, higher resting HR, and a greater MVO2.

Disease progression including natural history, disease phases or stages, disease trajectory (clinical features and presentation over time)

Table 1. Exercise Guidelines, by Disease Severity
Disease Severity Activity Guidelines ECG / BP Monitoring Supervision Required
Class A: Healthy individuals No restriction None required None
Class B: Known stable heart disease Individualized exercise prescription Only during prescriptive exercise Medical supervision during prescriptive sessions and nonmedical supervision for other exercise
Class C: Known stable heart disease and unable to self-regulate activity level Individualized exercise prescription and supervised by CPR-trained person Only during prescriptive exercise Medical supervision during prescriptive sessions and nonmedical supervision for other exercise
Class D: Moderate to high risk for complications during exercise Individualized exercise prescription Continuous during rehabilitation sessions Medical supervision during all rehabilitation sessions
Class E: Unstable disease (uncontrolled ischemia, heart failure, arrhythmia) No activity for conditioning purposes No conditioning program No conditioning program

Abbreviations: ECG, electrocardiogram; BP, blood pressure.

Specific secondary or associated conditions and complications

Often patients with cardiac disease have peripheral vascular disease and impaired respiratory function, which may also limit their mobility and exercise tolerance. Kidney and cerebral vascular disease are also prevalent in this population due to the same pathophysiology. The complications of cardiac disease and its associated conditions can increase the likelihood of mortality.

2. ESSENTIALS OF ASSESSMENT

History

Symptoms depend on the type of cardiac dysfunction present (Table 2).

Table 2. Symptoms Associated with Specific Cardiac Dysfunctions
Cardiac Dysfunction Symptoms
Congestive heart failure Dyspnea, orthopnea, edema, nocturia
Valvular dysfunction Dyspnea, fatigue, syncope or pre-syncope
Coronary artery disease Angina, (if ischemia, patient may complain of left- sided chest pain with radiation to left arm or jaw)
Arrhythmias Palpitations, syncope, dizziness
Peripheral arterial disease Claudication
Cardiomyopathy Dyspnea, edema, fatigue

Physical examination

Vitals:
Heart rate [HR]‑ Decreased in persons on beta-blockers or with conduction block or a pacemaker. HR is elevated in post cardiac transplant secondary to disruption of vagal innervation and in persons with certain arrhythmias. Blood pressure ‑ extremes of blood pressure and orthostasis may be present. Goal blood pressure is <140/90.5

Inspection:
Edema and elevated jugular venous pulse may be present in persons with CHF. Post bypass surgery patients should have sternotomy wound examined to exclude infection.

Palpation:
Displaced point of maximum impulse (PMI) indicates cardiomegaly.

Auscultation:
Lung exam may reveal crackles indicating pulmonary edema in CHF.
Heart sounds ‑ Arrhythmias, irregular rate or rhythm.
Murmurs indicate valvular pathology. Friction rub may be present in pericarditis.

Functional assessment

Cardiac patients often have lower exercise tolerance and cannot perform activities that require increased energy expenditure, such as walking, climbing stairs, or activities of daily living.  Functional capacity [FC] refers to the maximum ability of the heart and lungs to deliver oxygen and the ability of muscles to extract it. FC is measured by determining the maximal oxygen uptake (VO2max) during incremental exercise. The metabolic equivalent (MET) describes functional capacity [FC]. One MET equals 3.5 milliliters of oxygen consumed per kilogram of body weight per minute (3.5 mlO2/kg/min), equal to the amount of energy used at rest. Exercise testing can provide objective measures of exercise capacity and be helpful in exercise prescription. The Borg Perceived Exertion Scale, a linear scale from 6-20, may also be used to monitor exercise intensity. A score of 12-14 on this scale is typically considered a moderate level of activity.6 The talk test and target heart rate are also used to assess exercise intensity  

In patients with CHF and severe left ventricle dysfunction, the functional capacity can be evaluated more accurately using cardiopulmonary exercise (CPX) testing8, although most cardiac rehabilitation facilities are not equipped for CPX.

Factors that influence Functional Capacity are: age, fluid volume, left ventricle dysfunction, residual myocardial ischemia, deconditioning, diabetic neuropathy, peripheral vascular status, pulmonary status, and orthopedic problems limiting locomotion.

Laboratory studies

It is important to assess for cardiac risk factors including cholesterol, diabetes, or renal disease. Labs that may be indicated include lipid panel, fasting blood glucose, hemoglobin A1C, basic metabolic panel, beta-natriuretic peptide. A 12-lead electrocardiogram is necessary to evaluate for arrhythmias, conduction blocks, left/right heart strain, hypertrophy, and ischemia.

Imaging

Radiography of the chest may reveal cardiomegaly or pulmonary edema.

A transthoracic echocardiogram can assess for left ventricular function, pulmonary hypertension, valvular pathology, or wall motion abnormality.

A transesophageal echocardiogram permits a more accurate assessment of the cardiac valves and evaluates for any cardiac thrombus or vegetation.

Gated cardiac MRI can assess cardiac function and coronary anatomy.

Multi-gated acquisition scan (MUGA) can assess left and right ventricular function.

Thallium scan can assess for myocardial ischemia.

Supplemental assessment tools

Cardiac stress testing may be necessary to evaluate exercise tolerance and ischemic threshold. Graded exercise testing assesses the patient’s ability to tolerate increased physical activity, and helps establish appropriate limits for exercise therapy. The six-minute-walk test (6MWT) provides information about functional capacity, clinical improvements and prognosis.9 The distance one is able to walk over 6 minutes on a hard, flat surface. Cardiac function can be assessed in patients with lower extremity impairments by using an arm or wheelchair ergometer. An extra wide treadmill may accommodate patients requiring wheelchairs for mobility. For patients who cannot perform adequate exercise, a pharmacologic stress test is indicated (Persantine, adenosine, dobutamine).

Early predictions of outcomes

Patients with diabetes and CAD show less improvement in physical function and are less likely to adhere to rehabilitation programs. Patients who improve the most are those CAD patients whose baseline self reports in physical function are the lowest.10 Early cardiac rehabilitation also decreased total mortality and major adverse cardiac and cerebrovascular events during a 1 year follow up in patients with a history of ST-segment elevation myocardial infarction (STEMI) and non-STEMI.11 Exercise training improves heart rate recovery in patients with recent MI. Patients who had an increase in heart rate recovery by 12 beats per minute had better cardiac survival rates.12 Due to their unstable cardiac status, persons with Class E heart failure are discouraged from participating in conditioning exercises and are more likely to have poor outcomes.

Another important predictor of negative outcome in cardiac rehabilitation is clinical depression. This has been associated to variance in aerobic capacity and adherence to the rehabilitation program.13

Environmental

Cardiac patients may require environmental modifications and adaptive devices to compensate for their decreased tolerance for activity.

Social role and social support system

Patients who enjoy large social networks are more likely to attend and adhere to rehabilitation programs and sustain the behaviors associated to improved quality of life.14 Communication with the patient’s primary physician and family members is essential in order to help ensure medication adherence, lifestyle modification and exercise regimen. Patients must be committed to their rehabilitation program in order to succeed. Barriers to successfully completing a cardiac rehabilitation program include lack of employment, widowed status, and comorbidities such as arthritis.  Approximately 20-25% of patients with acute myocardial infarction present with depression, which, is associated with lower exercise capacity, less energy, more fatigue, and a reduced quality of life and sense of well-being.15,16

Professional Issues

Cardiac rehabilitation is underutilized in the United States.17 It is estimated that only 10%-20% of the eligible patients actually participate in cardiac rehabilitation each year.18 Women are significantly less likely than men to be referred for cardiac rehabilitation, and women with lower income are even less likely to be referred. Hispanic and black patients are less likely to be referred for cardiac rehabilitation than whites.

3. REHABILITATION MANAGEMENT AND TREATMENTS

Available or current treatment guidelines

The American Heart Association and the American Association of Cardiopulmonary Rehabilitation have delineated core components that all cardiac rehabilitation programs should provide as a secondary prevention program.4 These components aim to minimize cardiovascular risks, promote healthy behavior, patient adherence, and an active lifestyle for patients with cardiovascular disease.

Cardiac rehabilitation improves symptoms of angina, decreases symptoms of heart failure, lowers cholesterol levels, decreases mortality and reduces stress. Standard outpatient cardiac rehabilitation lasting 6-12 weeks is shown to improve physical function in patients with CAD by up to 15%.

At different disease stages (19)

new onset/acute:
The acute rehabilitation phase (phase 1), characterized by early mobilization with cardiac monitoring, is initiated in the hospital by trained therapists. Patients are encouraged to sit at the edge of bed or in a chair once medically stable. The goal of the acute, phase 1 program is for the patient to perform activities up to 4 METS and be discharged home on a home exercise program within 1-4 days.

Phase 1b uses inpatient rehabilitation (IRF, subacute setting) for patients of advanced age with multiple comorbidities who may have a difficult time with early mobilization and may progress more slowly. Typically these services last up to 2 weeks.

subacute:
Phase 2 is the outpatient, training, phase of cardiac rehabilitation, supervised by trained therapists. Typically, the cardiac training program is 3 sessions weekly for up to 8 weeks.

chronic/stable:
Phase 3, the maintenance phase of cardiac conditioning, is essential to the success of the program. This program is lifelong.

Coordination of care

A cardiac rehabilitation program requires coordinated care among the patient, cardiologist, pulmonologist and rehabilitation team (physiatrist, physical therapists, occupational therapists, social workers and nutritionist). The commitment to an active lifestyle, healthy diet, and adherence to pharmacologic treatment is a lifelong process requiring support of all involved in the patient’s care.20

Patient & family education

Patients and family members require instruction on how to maintain a heart healthy diet. Patients should learn how to monitor their blood pressure and blood glucose, control weight, and recognize the symptoms of heart failure, hypo/hyperglycemia, and hypo/hypertension. Motivational letters, telephone calls and home visits increase adherence to cardiac rehabilitation programs. Family support is essential in supporting patient’s lifestyle changes.

Emerging/unique Interventions

Magnetic Resonance Imaging (MRI) is being used to provide complementary information on LV function, regional perfusion, angiogenesis, myocardial viability and orientations of myocytes.  When used with contrast, images can better enhance myocardial perfusion and angiogenesis. Imaging with combined MRI and Positron Emission Tomography is under developed.21

Translation into practice: practice “pearls”/performance improvement in practice (PIPs)/changes in clinical practice behaviors and skills

Risk factor modification can be adjusted for any patient population. It is particularly important in persons who are physically handicapped, since their condition can often lead to accelerated cardiovascular disease. Physical challenges in this population may include weakness, spasticity, amputation, and balance problems. Training can be accomplished by modifying individualized conditioning programs and using adaptive equipment. Examples are arm crank ergometer, supine bicycle ergometer, and wheelchair ergometer for exercise testing. This equipment is available in many cardiopulmonary rehabilitation facilities.

4. CUTTING EDGE/EMERGING AND UNIQUE CONCEPTS AND PRACTICE

Cutting edge concepts and practice7,22

A ventricular assist device (VAD) is a mechanical circulatory apparatus designed to assist the right ventricle (RVAD), left ventricle (LVAD), or both (BiVAD). These VAD devices are often used as a bridge to heart transplant or for those not eligible for transplant.

Recent emerging techniques include trans-catheter aortic valve implantation for valvular disorders and fractionate flow reserve measurements for atherosclerotic lesion evaluation in PCI.

Studies show that exertional dyspnea can be alleviated and exercise tolerance improved in patients with CHF.

The study of cardiac rehabilitation in pulmonary hypertension patients is underway.

High-intensity interval training may improve the availability of services, permit more rapid improvement in exercise capacity, and facilitate better patient adherence.

5. GAPS IN THE EVIDENCE-BASED KNOWLEDGE

In spite of published research demonstrating the impact of cardiac rehabilitation in morbidity and mortality, this program is still considered underutilized.  Hospital level barriers are considered the most influencing reasons for this gap.

Some studies suggest a polymorphism of genes that can influence the known risk factors that lead to coronary heart disease. A stronger effect is seen in genes regulating the cholesterol mechanism and the predisposition to plaque adhesions. The mechanism is unknown. More studies are required to understand the interplay between genes and the environmental factors.23

A new risk factor for coronary artery disease is being discussed: sleep disordered breathing (SBD). This is characterized as repetitive apneas, arousals from sleep, and intermittent hypoxia.  It has been identified that those with SBD and who suffer an acute myocardial infarct have prolonged ischemia, and as a consequence a higher risk for ventricular dysfunction. It is not clear what is the relation between SBD and heart disease; neither the role that conventional therapy for SBD would have in a vulnerable heart.24

REFERENCES

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  2. Heart Disease Facts and Statistics. Center for Disease Control and Prevention. http://www.cdc.gov/heartdisease/facts.htm
  3. Risk factors and Coronary Artery Disease. American Heart Association. http://www.heart.org/HEARTORG/Conditions/More/MyHeartandStrokeNews/Coronary-Artery-Disease—Coronary-Heart-Disease_UCM_436416_Article.jsp#.VtwiE8HSnmQ
  4. Balady GJ, Williams MA, Ades PA, Bittner V, Comoss P, Foody JM, et al. Core components of cardiac rehabilitation/secondary prevention programs (2007 update):an AHA/AACVPR scientific statement. 2007; 115: 2675-2682.
  5. Jennings GL. A New Guideline on Treatment of Hypertension in those with Coronary Artery Disease: Scientific Statement from the American Heart Association, American College of Cardiology, and American Society of Hypertension about Treatment of Hypertension in Patients with Coronary Artery Disease. Heart Lung Circ. 2015, July 9.
  6. Perceived Exertion (Borg Rating of Perceived Exertion Scale). Measuring Physical Activity Intensity. Center for Disease Control and Prevention. http://www.cdc.gov/physicalactivity/basics/measuring/exertion.htm
  7. Reed JL, Pipe AL. The talk test: a useful tool for prescribing and monitoring exercise intensity. Current Opinion in Cardiology. Vol 29;August, 2014.
  8. Balady GJ, Arena R, Sietsema K, Myers J, Coke L, Fletcher GF, Forman D, Franklin B, Guazzi M, Gulati M, Keteyian SJ, Lavie CJ, Macko R, Mancini D, Milani RV. Clinician’s Guide to Cardiopulmonary Exercise Testing in Adults: A Scientific Statement From the American Heart Association. Circulation. 2010; 122: 191-225.
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  11. Junger C, Rauch B, Schneider S, Liebhart N, Rauch G, Senges J, Bestehorn K. Effect of early short-term cardiac rehabilitation after acute ST-elevation and non-ST-elevation myocardial infarction on 1-year mortality. Curr Med Res Opin. 2010; 26(4):803-11.
  12. Hai JJ, Siu CW, Ho HH, Li SW, Lee S, Tse HF. Relationship between changes in heart rate recovery after cardiac rehabilitation on cardiovascular mortality in patients with myocardial infarction. Heart Rhythm.2010;7(7):929-36.
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  14. Molloy GJ, Perkins-Porras L, Strike PC, Steptoe A. Social networks and partner stress as predictors of adherence to medication, rehabilitation attendance, and quality of life following acute coronary syndrome. Health Psychol. 2008; 27(1):52-8.
  15. Shen BJ, Myers HF, McCreary CP. Psychosocial predictors of cardiac rehabilitation quality-of-life outcomes. J Psychosomat Res.2006; 60 (1):3-11.
  16. Turner SC, Bethell HJ, Evans JA, Goddard JR, Mullee MA. Patient characteristics and outcomes of cardiac rehabilitation. J Cardiopulmonary Rehabil. 2002; 22 (4):253-60.
  17. Parkosewich JA. Cardiac rehabilitation barriers and opportunities among women with cardiovascular disease. Cardiol Rev. 2008; 16:36.
  18. Sanderson BK. The ongoing dilemma of utilization of cardiac rehabilitation services. J Cardiopulmonary Rehabil. 2005; 25: 350-353.
  19. Singh VN, Schocken DD. Cardiac Rehabilitation: overview, history and definition of cardiac rehabilitation, patient selection and risk stratification. http://emedicine.medscape.com/article/319683-overview?src=emailthis
  20. Davies P, Taylor F, Beswick A, Wise F, Moxham T, Rees K, Ebrahim S. Promoting patient uptake and adherence in cardiac rehabilitation. Cochrane Database Syst Rev. 2010: Issue7. CD007131. DOI:10.1002/14651858.CD007131.pub2.
  21. Saeed M, Van TA, Krug R, Hetts SW, Wilson MW. Cardiac MR imaging: current status and future direction. Cardiovasc Diagn Ther. 2015 Aug;5 4):290-310.
  22. Humphrey R, Bartels M. Exercise, cardiovascular disease, and chronic heart failure. Arch Phys Med Rehabil. 2001; 82 (suppl 1):S76-81.
  23. Barth AS, Tomaselli GF. Gene scanning and heart attack risk. Trends Cardiovasc Med. 2015; July 17.
  24. Arzt M, Hetzenecker A, Steiner S, Buchner S. Sleep-Disordered breathing and coronary artery disease. Can J Cardiol. 2015; Jul; 31(7): 909-17.

Original Version of the Topic:  

Anna-Christina Bevelaqua, MD, Matthew Bartels, MD, Annemarie Gallagher, MD. Cardiac Rehabilitation. Publication Date:  2011/12/09.

Author Disclosure

Maricarmen Cruz, MD
Nothing to Disclose

Isabel Borras, MD
Nothing to Disclose

Jose Cumba, MD
Nothing to Disclose

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