Cardiology

Exercise Training and Heart Failure

General description of procedure, equipment, technique

General overview

Heart failure is a common cause of morbidity, mortality, and disability affecting over 5 million patients in the United States. Although evidence-based pharmacologic and device therapy have decreased mortality, hospitalizations, and heart failure symptoms and improved quality of life, many patients treated with these regimens often remain burdened by dyspnea and fatigue, diminished exercise tolerance, reduced quality of life, recurrent hospitalizations, and early mortality.

The mechanisms hypothesized to contribute to exercise intolerance in heart failure patients include physical deconditioning, impairment of central circulation, ventilation, and peripheral muscle function, endothelial dysfunction, autonomic nervous system dysregulation, and chronic inflammation. Randomized, controlled trials have documented the impact of exercise training on these processes and have confirmed the benefit of this therapy.

Until recently, there were concerns that exercise training may be dangerous in the heart failure population owing to potential ischemic events and/or arrhythmias. Although several small studies indicated that exercise was safe in heart failure populations, they were not adequately powered to assess morbidity and mortality.

Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) is a multicenter, randomized controlled trial of 2,331 medically stable outpatients with heart failure and reduced ejection fraction that was published in 2009. HF-ACTION confirmed that exercise training was well-tolerated and safe in this population. Of the 1,159 patients randomized to exercise training in HF-ACTION, only one patient had an implantable cardioverter defibrillator (ICD) discharge during exercise.

Indications and patient selection

Most of the literature on exercise and heart failure focuses on patients with heart failure with reduced ejection fraction. Small, single-center studies have been conducted on exercise training in patients with preserved ejection fraction. These patients are usually elderly with multiple comorbidities. Based on limited data, it appears that exercise training is safe in this population as well.

Contraindications

Exercise should not be recommended in patients with unstable angina or patients with unstable arrhythmias. Patients with symptomatic aortic stenosis are at risk of adverse events with exercise.

Patients with implantable cardioverter defibrillators should have their heart rate limits set higher than the target heart rate for exercise training. Exercise training has not been studied in patients with decompensated heart failure, so it is unclear if exercise is safe in this population.

Details of how the procedure is performed

Testing prior to exercise training

It is recommended that patients undergo exercise testing prior to initiation of a training program. There are several options depending on the equipment available at your facility and the proficiency of personnel available to administer and interpret the results of the test.

The most comprehensive assessment of exercise capacity is cardiopulmonary exercise (CPX) testing. CPX testing is an exercise stress test with concurrent measurement of respiratory gas exchange via use of a metabolic cart.

CPX directly measures VO2, VCO2, and air flow (minute ventilation [VE], tidal volume and respiratory rate) on a breath-by-breath basis using a nonrebreathing valve connected to a metabolic cart. Samples of expired air are typically assessed every 15 seconds, and real-time data are expressed in both a tabular and graphic format.

Additionally, oxygen saturation using finger or ear oximetry is monitored and recorded. From these data, numerous clinically relevant metabolic parameters can be derived including peak VO2, VO2max, breathing rate, anaerobic threshold, respiratory exchange ratio, O2 pulse, ventilation/carbon dioxide production ratio, and peak VO2 lean.

CPX testing can help predict survival in patients with systolic heart failure and has been used to help selection of patients for advanced therapies such as transplantation and mechanical circulatory support . According to the 2006 International Society for Heart and Lung Transplantation guidelines, in patients intolerant of a beta-blocker, a cutoff for peak VO2 <14 ml/kg/min should be used to guide listing for transplantation. In the presence of a beta-blocker, a cutoff for peak VO2 <12 ml/kg/min should be used to guide listing.

The choice of exercise stress testing to assess exercise capacity is important. Exercise test protocols with large stage-to stage increments in energy requirements generally have a weaker relationship between measured VO2 and work rate. Therefore, it is recommended that protocols with more gradual stage-to-stage increments are used in the heart failure population.

Two commonly used methods of CPX are the Balke and Ware protocol and the modified Naughton protocol. The Balke and Ware protocol is a treadmill test with a constant speed of 3.5 mph and a 1% increase in incline each minute to a maximum incline of 22%.

The modified Naughton protocol is an incremental exercise test on a treadmill with 2-minute stages and increments in both gradient and velocity simulating increments of about 1 metabolic equivalent. The chosen protocol should be tailored to the individual to yield a fatigue-limited exercise duration of approximately 8 to 12 minutes.

Patients will often terminate a test that is >12 minutes for reasons other than fatigue, such as orthopedic issues. If the anticipated duration of exercise is estimated to be >12 minutes, a protocol that increases the work rate more progressively such as Bruce protocol may be considered.

The Bruce protocol is a treadmill test that increases in both velocity and incline every 3 minutes. Bicycle ergometry can also be used, although in the United States, subjects frequently terminate the test due to quadriceps fatigue that is on average 10% to 20% below their treadmill peak VO2. If your facility does not have the equipment or personnel to perform CPX testing, an exercise stress test can provide valuable information prior to implementing an exercise program. Not only can you assess for ischemia and arrhythmias, but the information obtained can assist with exercise prescription.

Details of exercise training

Both endurance and resistance training have proven beneficial in the heart failure population. Most exercise programs in the literature are based on the cardiac rehabilitation model of a facility-based supervised exercise program comprised of 36 sessions followed by transition to a home-based program.

The endurance component is commonly comprised of walking or cycling. There is no clear consensus on the intensity of aerobic exercise that is needed to achieve benefit.

In HF-ACTION, the heart rate reserve (HRR) method was used to guide exercise intensity. Peak heart rate is derived from the patient's cardiopulmonary exercise test or exercise stress test; the resting heart rate is taken after 5 minutes of quiet seated rest.

For the first six supervised exercise training sessions, the training heart rage range was computed at 60% of the HRR (resting heart rate + 0.6 [peak heart rate – resting heart rate]). Initially, the goal was to exercise at 50% of the HRR for 15 to 30 minutes.

Training intensity was increased to a range of 60% to 70% of the HRR for the rest of the supervised exercise training sessions and the home-based training phase. The goal duration of aerobic exercise was 40 minutes five times per week. For patients who are in persistent atrial fibrillation or who have frequent ventricular beats that make exercise prescription by the HRR invalid, the rate of perceived exertion (RPE) was used.

Interval training has also been examined in a heart failure population. The rationale for interval training is that it allows for rest periods that make it possible for patients with heart failure to complete short work periods at a higher intensity that would not be possible during continuous exercise.

Wisloff et al. randomized 27 patients with an average age of 75 years with ischemic heart disease and an ejection fraction (EF) <40% to either moderate continuous training at 70% of peak heart rate versus aerobic interval training at 95% of peak heart rate. The aerobic interval training consisted of a 10-minute walk up at 60% to 70% of peak heart rate followed by four, 4-minute intervals of uphill treadmill walking at 90% to 95% of peak heart rate.

There were no deaths or adverse events reported in the aerobic interval training group. The authors concluded that aerobic interval training was superior to moderate continuous training in patients with postinfarction heart failure with regard to reversal of left ventricular (LV) remodeling, aerobic capacity, endothelial function, and quality of life.

Although initial studies have supported the concept of interval training, the authors currently recommend a program of continuous exercise if tolerated. Interval training should be considered to improve adherence for those patients who find this type of training easier to complete.

In several small studies, resistance training was included in the exercise regimen. No serious adverse events were reported, indicating that moderate resistance training is likely safe in heart failure patients.

Examples of resistance exercises included in the studies are bench press, leg press, leg curl, rowing machine, triceps dips, bicep curls, latissimus pull down, calf raises, back extensions, and sit ups. Ten to 15 repetitions are recommended per exercise at 80% of the patient's one repetition maximum. Resistance training should be performed two to three times per week.

If patients are unable to participate in a facility-based exercise program due to financial constraints or transportation issues, a home-based program can be prescribed. Dracup et al conducted a study with 173 patients with systolic heart failure randomized to a control group versus a low intensity home exercise program consisting of walking and resistance training.

Although there was no significant difference in the composite primary endpoint of all-cause hospitalizations, emergency room admissions, urgent transplantation, and death at 12 months, there was a statistically significant decrease in hospital admissions. The authors hypothesize that further improvement may have been seen in the intervention group if they exercised at a higher intensity.

There were no adverse outcomes reported in the Dracup study or the home exercise component of HF-ACTION, indicating that home exercise training in heart failure patients is safe. If home exercise training is prescribed, patients should be trained in the use of a heart rate monitor to achieve a target heart rate of 60% to 70% of HRR for the aerobic component of the exercise program.

They should be provided with reference material such as handouts or videos for the resistance component. Patients should be adequately trained in performing a home exercise program to prevent injury and facilitate adherence.

A summary of trials of exercise training and the exercise programs used is included in Table I and Table II.

Table I.

Controlled Trials of Exercise Training in Heart Failure That Have Shown Improvements in Peak VO2
Author (Year Published) Number of Patients Exercise Program % VO2 IncreaseOutcome vs. Controls
Jette (1991) 18 4-wk program: Monday-Friday, AM: Jog at 70%-80% max HR, 5 min, 3x/wk; 30 min calisthenics; cycle 15 min 70%-80% max HR. PM: Walking 30-60 min 22 in group with EF <30%
Belardinelli (1992) 20 Cycle at 60% VO2 peak x 3 wk 20
Coats (1992) 17 Cycle 20 min 3x/wk; 60%-80% max HR, 8 wk 18
Belardinelli (1995) 55 Cycle 40 min 3x/wk; 60% VO2max; 8 wk 12
Hambrecht (1995) 22 10 min 6x/day 70% VO2max x 3 wk 31
Keteyian (1996) 29 RPE 12-14; 60% exercise capacity 33 min 3x/wk x 24 wk 16.3
Radaelli (1996) 6 Cycle 20 min x 5 day/wk x 5 wk 15
Dubach (1997) 25 Walk 60 min 2x/day; cycle 40 min 4x/wk at 80% VO2 max, 4 wk 26
Tyni-Lenné (1997) 16 Knee extensor for 8 wk 14
Callaerts-Vegh (1998) 17 Walking 1 hr, 2x/day; 45 min cycle at 70%-80% HR reserve, 4x/wk; 8 wk 30.9
Reinhart (1998) 25 Cycle 40 min at 70%-80% max capacity 4x/wk; walk 1 hour 2x/day, 8 wk 29
Belardinelli (1999) 99 Cycle 60% peak VO2, 8 wk, 3 x/wk; maintenance, 12 mo, 2 x/wk 18 at 2 mo 23 at 14 mo
Taylor (1999) 8 Training 3 x/wk; 30 min; 45%-70% peak VO2 x 8 wk 17.6
Sturm (1999) 26 50% capacity x 12 wk, then 100 min step aerobics/wk + cycle 50 min/wk 23.3
Keteyian (1999) 43 60%-80% max HR; 33 min, 3 x/wk x 24 wk 14.3

Table II.

Trials of Exercise Training That Have Shown Improvements in Clinical and Biologic Parameters Other Than VO2 )
Author (Year Published) Exercise Program Improvement
Kiilavuori (1999) Cycle 30 min 3x/wk at 50%-60% max VO2 Plasma norepinephrine decreased at rest No adverse effects on catabolic hormones
Coats (1992) Cycle 20 min 3x/wk; 60%-80% max HR, 8 wk Improved heart rate variability Decreased ventilation
Belardinelli (1995) Cycle 40 min 3x/wk 60% VO2max; 8 wk Improved indices of diastolic function
Hambrecht (1995) 10 min 6x/day 70% VO2max x 3 wk Muscle mitochondria volume density increased
Radaelli (1996) Cycle 20 min x 5 day/wk x 5 wk Improved autonomic control of HR
Tyni-Lenné (1997) Knee extensor for 8 wk Increased citrate synthetase, lactate dehydrogenase; improved QOL
Belardinelli (1999) Cycle 60% peak VO2, 8 wk, 3x/wk; maintenance, 12 mo, 2x/wk Fewer hospital readmissions for heart failure and reduced mortality
Taylor (1999) Training 3x/wk x 8 wk Peak cardiac index increased by 10%
Keteyian (1999) 60%-80% max HR, 33 min,3x/wk x 24 wk Improved chronotropic response to exercise
Maiorana (2000) Circuit weight training x 8 wk Isotonic voluntary contractile skeletal muscle strength increased by 17.9%

Interpretation of results

In a research setting, multiple parameters are measured after several weeks to months of initiating an exercise program to assess efficacy, including peak VO2, 6-minute walk test, biomarkers including brain natriuretic peptide, tumor necrosis factor, C-reactive protein, and quality of life measures, such as the Kansas City Cardiomyopathy Questionnaire, 36-Item Short-Form Health Instrument, and Minnesota Living with Heart Failure Questionnaire. Many of these assessment tools may be impractical and cumbersome in a clinical setting and may not provide useful information regarding efficacy on a patient-to-patient basis.

It is important to assess clinical parameters such as New York Heart Association Functional Class during each office visit. Repeat exercise stress testing after several months of an exercise program may be helpful to demonstrate objective improvement in patients' performance, which can help with adherence. Adherence should be addressed at each session.

Outcomes (applies only to therapeutic procedures)

Benefits and success rates of exercise training

The ExTraMATCH Collaborative published a meta-analysis in 2004 to determine the effect of exercise training on survival in patients with heart failure due to left ventricular systolic dysfunction. They included nine data sets with a total of 801 participants in randomized parallel group controlled trials of exercise training for at least 8 weeks with individual patient data on survival for at least three months.

They concluded that exercise training significantly reduced mortality (hazard ration 0.65, 95% confidence interval (CI), 0.46 to 0.92; log rank x2 = 5.9; P = .015). Hospital admissions were also significantly reduced. A limitation to this meta-analysis is that the trials included were single-center studies, which often showed larger treatment effects than multi-center trials.

In the primary analysis of HF-ACTION, exercise training resulted in a nonsignificant reduction in the all-cause mortality or hospitalization. After adjustment for high prognostic predictors of the primary endpoint, including duration of the cardiopulmonary exercise test, left ventricular ejection fraction, Beck Depression Inventory II Score, and history of atrial fibrillation or flutter, exercise training was associated with modest significant reduction for both all-cause mortality or hospitalization and cardiovascular mortality or heart failure hospitalization.

HF-ACTION also showed that exercise training conferred modest but statistically significant improvements in self-reported health status compared with usual care without training. Improvements occurred early and persisted over time.

Importantly, 94% of the patients participating in HF-ACTION were receiving beta-blockers and angiotensin-receptor blockers or angiotensin-converting enzyme inhibitors. Forty-five percent had an implantable cardioverter defibrillator (ICD) or implanted biventricular pacemaker at the time of enrollment.

Given the proven survival advantage of these medical treatments, any incremental all-cause mortality benefit with exercise is likely to be small. Regarding exercise training effects, patients in the exercise-training group in HF-ACTION had a greater improvement in distance in the 6-minute walk test, in exercise time on cardiopulmonary exercise test, and in peak oxygen consumption.

In 2010, a Cochrane review was published on exercise-based rehabilitation for heart failure. The review included randomized control trials of exercise-based interventions with 6 months follow-up or longer compared to usual medical care or a placebo.

The study population included adults with evidence of chronic systolic heart failure. Nineteen trials with a total of 3,647 participants met the inclusion criteria. Of note, HF-ACTION recruited 2,331 of these participants.

The review concluded that there was no difference in pooled mortality between groups in the 13 trials with <1-year follow-up. There was evidence of a nonsignificant trend toward reduction in pooled mortality with exercise in the four trials with >1-year follow-up.

A reduction in the hospitalization rate was demonstrated with exercise training programs. There was also an improvement in health-related quality of life.

To date, there are no studies adequately powered to assess all-cause mortality or hospitalizations in patients with heart failure with preserved ejection fraction. ExDHF (Exercise Training in Diastolic Heart Failure) is a pilot study assessing whether structured exercise training improves maximal exercise capacity, left ventricular diastolic function, and quality of life in patients with heart failure with preserved ejection fraction.

Sixty-four patients were randomized in a 2:1 fashion to receive supervised endurance/resistance training for 32 sessions versus usual care. The authors concluded that exercise training improves exercise capacity and physical dimensions of function.

Kitzman et al also published a randomized control trial randomizing 53 elderly patients with heart failure with preserved ejection fraction to a 16-week medically supervised exercise program versus attention controls. Significant improvements were noted in peak power output, exercise time, 6-minute walk distance, and ventilatory anaerobic threshold.

There was also improvement in the physical quality of life score in the Minnesota Living with Heart Failure Questionnaire, but not the total score. They concluded that exercise training improves peak and submaximal exercise capacity in older patients with heart failure with preserved ejection fraction.

Alternative and/or additional procedures to consider

In addition to exercise, it is important that patients with heart failure are optimally medically managed with evidence-based drug and device therapy.

Complications and their management

Although few adverse events occurred in HF-ACTION or the other smaller studies involving exercise in heart failure patients, there are issues that may arise. Many patients with heart failure have ICDs that may inappropriately fire if patients achieve a heart rate that is higher than the parameters set on the devices.

Patients with atrial fibrillation may encounter issues not only with inappropriate ICD firing due to potential rapid ventricular response with exercise, but difficulty achieving the recommended intensity goal with exercise because they are unable to use heart rate as a guide. In this situation, the rate of perceived exertion (RPE) scale can be used.

Adherence is an obstacle to any exercise program but may be more problematic in the heart failure population due to baseline dyspnea, fatigue, and frequent exacerbations. Despite the close monitoring and extensive resources provided, including treadmills and stationary bikes for home use, only 30% of the 1,159 subjects in the training group of the HF-ACTION study were adherent to the program as prescribed.

Below are suggestions that may facilitate adherence to an exercise program in the heart failure population:

  • Assess your patients' readiness for change using the Stages for Motivational Readiness for change model.

  • Encourage the patients to sign a behavioral contract that outlines their responsibilities.

  • If your patients will be participating in a facility-based exercise program, ensure the patients have adequate transportation to get to the facility.

  • Screen for and treat depression and anxiety.

  • Encourage patients to exercise in groups.

  • Use social support mechanisms such as spouses, family, and friends to encourage the patients.

  • Encourage use of the heart rate monitors so the patients get physiologic feedback about their performance.

  • If your patients will be participating in a home exercise program, ensure that they are comfortable performing the exercise program and using all recommended equipment.

  • Encourage your patients to keep an exercise log, including the mode of exercise, time, intensity, and symptoms.

  • Reassess patients' exercise programs frequently and adjust when necessary so that the participants remain engaged and challenged.

What’s the evidence?

O'Connor, CM, Whellan, DJ, Lee, KL. "Efficacy and safety of exercise training in patients with chronic heart failure HF-ACTION randomized control trial". JAMA. vol. 301. 2009. pp. 1439-50.

Flynn, KE, Pina, IL, Whellan, DJ. "Effects of exercise training on health status in patients with chronic heart failure HF-ACTION randomized control trial". JAMA. vol. 301. 2009. pp. 1451-59.

Whellan, DJ, O'Connor, CM, Lee, KL. "Heart failure and a controlled trial investigating outcomes of exercise training (HF-ACTION): Design and rationale". Am Heart J. vol. 153. 2007. pp. 201-11.

Downing, J, Balady, GJ. "The role of exercise training in heart failure". J Am Coll Cardiology. vol. 58. 2011. pp. 561-9.

Kitzman, DW, Brubaker, PH, Morgan, TM. "Exercise training in older patients with heart failure and preserved ejection fraction". Circ Heart Fail. vol. 3. 2010. pp. 659-67.

Edelmann, F, Gelbrich, G, Dungen, H. "Exercise training improves exercise capacity and diastolic function in patients with heart failure with preserved ejection fraction". J Am Coll Cardio. vol. 58. 2011. pp. 1780-91.

Wisloff, U, Soylen, A, Loennechen, JF. "Superior cardiovascular effect of aerobic interval training versus moderate continuous training in heart failure patients". Circulation. vol. 115. 2007. pp. 3086-94.

Davies, EJ, Moxham, T, Rees, K. "Exercise based rehabilitation for heart failure (review)". www.thecochranelibrary.com.

Milani, RV, Lavie, CJ, Mehra, MR. "Cardiopulmonary exercise testing: How can we differentiate the cause of dyspnea?". Circulation. vol. 110. 2004. pp. e27-31.

Balady, GJ, Arena, R, Sietsema, K. "Clinician's guide to cardiopulmonary exercise testing in adults: A scientific statement from the American Heart Association". Circulation. vol. 121. 2010. pp. 191-225.

"ExTRAMATCH Collaborative. Exercise training meta-analysis of trials in patients with chronic heart failure (ExTRAMATCH)". BMJ. vol. 328. 2004. pp. 189.

Dracup, K, Evangelista, LS, Hamilton, MA. "Effects of home exercise program on clinical outcomes in heart failure". Am Heart J. vol. 154. 2007. pp. 877-83.

Mehra, MR, Kobashigawa, J, Starling, R. "Listing criteria for heart transplantation: International Society for Heart and Lung Transplantation guidelines for the care of cardiac transplant candidates—2006". J Heart Lung Transplant. vol. 25. 2006. pp. 1024-42.

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