Exercise performance of the high risk acute myocardial infarction patient after cardiac rehabilitation

Benefits of cardiac rehabilitation in heart failure patients according to etiology: INCARD French study

We investigated the impact of heart failure (HF) etiology on the outcome of cardiac rehabilitation (CR) assessed by functional and clinical parameters. Treatment of chronic HF requires multidisciplinary approaches with a recognized role for CR. INCARD is a French study aimed at evaluating the benefits of sustainable CR in coronary (C) and noncoronary patients (NC) treated and educated during a 24-month period of follow-up. Prospective, monocentric patients with HF underwent inpatient physical training followed by a home-based program. Evaluations were performed at inclusion, discharge, 3 months after discharge, and subsequently every 6 months over the 24 months of outpatient rehabilitation.A total of 147 HF patients with left ventricular ejection fraction (LVEF) <40 were admitted to the CR center, 63 accepted to join INCARD (29 C and 34 NC). Although the C participants C having both an echocardiographic LVEF and an initially lower peak VO2, inpatient rehabilitation improved all functional parameters. Only NC showed an improved LVEF during the first 3 months of outpatient-follow-up. The main outcome of the outpatient rehabilitation was a trend toward stabilization of clinical and laboratory parameters with no significant difference between C and NC. This study confirms the benefits of initial HF inpatient rehabilitation and encourages prolonged outpatient monitoring. The results on functional parameters suggest exercise training should be conducted regardless of the HF etiology.

Patients with large myocardial infarction gain a greater improvement in exercise capacity after exercise training than those with small to medium infarction

BACKGROUND

It remains unclear whether patients with large-size myocardial infarction (MI) achieve the same benefit from exercise training as do those with small- to medium-size MI.

HYPOTHESIS

This study was designed to determine the magnitude and mechanisms underlying improvement in exercise capacity in patients with large-size MI after cardiac rehabilitation.

METHODS

In all, 296 patients who participated in a cardiac rehabilitation program after acute MI were divided into two groups according to the peak serum creatine phosphokinase (CPK) level: the group with large infarction (Group 1) (> or = 5000 U/l peak CPK, 64 patients) and the group with less extensive infarction (Group 2) (< 5000 U/I, 232 patients). Exercise capacity was assessed before and after a 3-month cardiac rehabilitation program that included exercise training.

RESULTS

Before exercise training, both the peak work rate (p < 0.05) and peak oxygen uptake (VO2) (p < 0.01) were significantly lower in Group 1 than in Group 2. After exercise training, the changes in peak work rate and peak VO2 were significantly greater in Group 1 than in Group 2 (both p < 0.01). The infarction size measured by the peak CPK level correlated significantly with both the baseline exercise capacity and its improvement after exercise training, although these correlations were insignificant in a multivariate analysis. In the multivariate analysis, the improvement in exercise capacity is determined by age and baseline exercise capacity, which is determined by the duration of inactivity, minute ventilation (VE)/VCO2 slope and left ventricular end-diastolic pressure.

CONCLUSIONS

Compared with patients with small- to medium-size myocardial infarction, patients with large infarction gain a greater improvement in exercise capacity after exercise training due to reversal of physical deconditioning and improvement in congestive heart failure.

Exercise programmes for patients with chronic heart failure

The safety and efficacy of exercise training in patients with chronic heart failure (CHF) have been reported in a large number of scientific studies, with endurance training representing the most frequently applied training stimulus. Beneath the common continuous method of endurance training, the interval method (short bouts of intense exercise interspersed with pre-scheduled rest intervals), was also applied in some studies. Ergometric testing is a prerequisite for all individualised training prescription and is an appropriate method of efficacy documentation. However, there is a surprisingly large range of exercise intensities being prescribed to patients with CHF. Most of the prescription models refer to maximal ergometric measurements. Submaximal references from lactate and ventilatory curves represent an alternative method in measuring accuracy and efficacy of training. The course of heart rate during submaximal incremental exercise can be reliably used to indicate endurance gains in CHF. Some positive reports exist for carefully executed strength endurance training for patients with CHF and there are convincing arguments for the use of coordination and flexibility exercises; however, substantial scientific evidence is lacking.

Predictors of Left Ventricular Remodeling in Patients With Acute Myocardial Infarction Participating in Cardiac Rehabilitation-Brain Natriuretic Peptide and Anterior Infarction-

BACKGROUND

This study was designed to determine the factors influencing the development of left ventricular (LV) remodeling in patients participating in a comprehensive cardiac rehabilitation (CR) program after acute myocardial infarction (AMI), with special reference to exercise intensity and frequency.

METHODS AND RESULTS

A total of 72 patients with AMI participated in CR consisting of exercise training of moderate intensity (heart rate reserve 40-60%) and education for 12 weeks. Plasma concentration of brain natriuretic peptide (BNP) was measured at the beginning and the end of CR. Echocardiography was performed before and 1 year after CR. An increase in LV end-diastolic dimension (delta-LVDd) from baseline was used as an index of remodeling. Delta-LVDd was significantly greater in patients with an anterior AMI than with other infarct locations (p<0.05) and correlated significantly with baseline BNP concentration (p<0.05). Delta-LVDd >5 mm occurred exclusively in patients with baseline BNP >150 pg/ml. Variables representing the intensity and frequency of exercise training did not correlate with delta-LVDd.

CONCLUSIONS

In patients with AMI participating in CR, those having both anterior infarction and baseline BNP concentration >150 pg/ml are at high risk for subsequent LV remodeling, whereas neither exercise intensity nor participation frequency in CR appears to be associated with LV remodeling.

Exercise training without ventricular remodeling in patients with moderate to severe left ventricular dysfunction early after acute myocardial infarction

BACKGROUND

The purpose of this study was to determine whether or not patients with moderate to severe left ventricular (LV) dysfunction benefit from exercise training starting early after acute myocardial infarction (AMI) without deteriorating LV remodeling.

METHODS

We investigated changes in exercise capacity and LV end-diastolic dimension (LVDd by two-dimensional echocardiography) before and after exercise training in 126 patients after AMI. Patients were divided into three groups according to LV ejection fraction (EF) at the beginning of exercise training: 74 patients with LVEF>/=45% (Group H), 35 patients with 35%</=LVEF<45% (Group M), and 17 patients with LVEF<35% (Group L). Exercise training was prescribed at a moderate intensity (50-60% of heart rate reserve or Karvonen's equation). Exercise capacity was assessed by peak work rate (WR) and peak oxygen uptake (VO(2)) by upright cardiopulmonary exercise test before and after 3 months of exercise training. LVDd was measured before and at 27+/-10 months of follow-up period.

RESULTS

At the baseline, Group L had a significantly lower LVEF (H 55+/-7 vs. M 40+/-3 vs. L 30+/-3%, P<0.05), significantly greater LVDd (49+/-6 vs. 52+/-7 vs. 56+/-6 mm, P<0.05), and a higher incidence of anterior infarction (P<0.01) compared with Groups H and M, whereas there were no difference in age, sex, coronary risk factors, the incidence of multivessel disease, prior myocardial infarction, peak WR or peak VO(2) among the three groups. After 3 months of exercise training, exercise capacity increased significantly (all P<0.01) in all groups. The magnitudes of the increases in peak VO(2) (%Deltapeak VO(2): 18+/-20 vs. 15+/-19 vs. 18+/-17%, NS) and peak WR (%Deltapeak WR: 17+/-17 vs. 16+/-14 vs. 15+/-13%, NS) were similar among the three groups. In addition, there was no significant correlation between %Deltapeak VO(2) and baseline LVEF. No increase in LVDd was observed in any group at follow-up (H 48+/-5 to 49+/-4 mm vs. M 53+/-8 to 52+/-8 mm vs. L 57+/-5 to 57+/-7 mm, NS in each group).

CONCLUSION

Patients with moderate to severe LV dysfunction benefit from exercise training starting early after AMI without deteriorating LV remodeling, with a similar magnitude of improvement in exercise capacity to that in patients with mild LV dysfunction.

Effects of exercise training on LV performance and mortality in a murine model of dilated cardiomyopathy

Dilated cardiomyopathy (DC) is a leading cause of cardiovascular morbidity, and nonpharmacological therapies, such as exercise training, have been suggested. The effects of exercise on left ventricular (LV) function and mortality remain controversial. Using a recently described murine model of DC, which involves a dominant-negative form of the cAMP response element binding protein (CREB) transcription factor (CREB(A133)) under the control of the cardiac myocyte-specific alpha-myosin heavy chain promoter, we sought to assess the effects of moderate-intensity exercise training on LV performance and mortality. Thirty-two transgenic mice were subjected to exercise training and compared with sedentary controls. There was progressive enlargement in LV dimensions in both the sedentary and exercise-trained mice. LV performance was progressively impaired, and exercise training did not prevent this decline. The sedentary CREB(A133) mice displayed a significantly increased rate of death, and exercise training did not prevent or delay this excess mortality. The CREB(A133) murine model of inherited DC demonstrated progressive ventricular dilatation and dysfunction with increased mortality, which was not altered with 12 wk of moderate-intensity exercise training.

Improvement in corrected QT dispersion by physical training and percutaneous transluminal coronary angioplasty in patients with recent myocardial infarction

The aim of the present study was to assess whether physical training and percutaneous transluminal coronary angioplasty (PTCA) improve the corrected QT (QTc) dispersion in patients with recent myocardial infarction (MI). Twenty-four patients with recent MI were allocated to one of 3 groups: training (n = 8), PTCA (n = 7) or controls (n = 9). Physical training as well as PTCA decreased QTc dispersion, whereas QTc dispersion increased in the control group. Changes in QTc dispersion after physical training or PTCA were inversely correlated with exercise-induced ST depression at the baseline test. These observations suggest that physical training, as well as PTCA, could improve QTc dispersion and electrical instability in patients with recent MI, possibly due to improvement of myocardial ischemia.

Exercise training in heart failure

Patients with heart failure challenge the clinician with a constellation of difficult clinical, pathophysiologic, and psychologic issues. As a result, until recently, exercise training was not considered a safe and effective treatment strategy to be used in these patients. However, in the past 10 years, data from both randomized and nonrandomized trials showed that regular exercise training in patients with stable Class II and III heart failure can safely improve exercise tolerance, attenuate an overactivated sympathetic nervous system, partially reverse skeletal muscle abnormalities, and enhance health-related quality of life. These outcomes are achievable with a relatively moderate dose of physical activity, such as 30 to 60 minutes of walking or cycling 3 to 5 days per week at an intensity equivalent to 60% to 70% of peak oxygen consumption. Sufficiently powered trials are needed to assess morbidity, mortality, and cost-effectiveness endpoints relative to exercise training in patients with heart failure.

Exercise training in patients with CHF and heart transplant recipients

The number of chronic heart failure (CHF) patients and heart transplantation (HT) recipients enrolled in rehabilitation and maintenance exercise programs continues to expand. There is growing clinical consensus that stable patients with CHF respond favorably to exercise training and convincing evidence that exercise training should be an essential adjunct therapy in postoperative management of HT recipients. This review examines the following specific advances in exercise physiology for heart failure and heart transplantation patients: 1) the mechanisms of exercise intolerance in CHF and the results of exercise rehabilitation studies in these patients; 2) the exercise challenges conferred by glucocorticoid therapy and chronic cardiac denervation in HT recipients; and 3) a summary of current recommendations and guidelines for exercise prescription in each patient population.

Evidence for the effectiveness of cardiac rehabilitation

Cardiac rehabilitation is a relatively recent development and, though it is increasingly being recognized as an important part of comprehensive cardiac care, there remains some scepticism regarding its effectiveness and some ignorance of its potential. This article reviews the literature pertaining to the effectiveness of cardiac rehabilitation for patients with coronary heart disease (CHD).

Metabolic abnormality of calf skeletal muscle is improved by localised muscle training without changes in blood flow in chronic heart failure

OBJECTIVE

To investigate whether localised skeletal muscle training, which does not have a great influence on the heart, improves abnormalities of calf muscle metabolism in patients with chronic heart failure.

METHODS

Seven cardiac patients in New York Heart Association class II and III undertook a random order crossover trial. Training consisted of unilateral calf plantar flexion exercise. Before and after training, the patients' metabolic responses were examined during the calf exercise test with phosphorus-31 nuclear magnetic resonance spectroscopy (31P-MRS) and calf blood flow with plethysmography. The new Borg scale was employed as a subjective fatigue scale.

RESULTS

In a constant load exercise test (70% of maximum load achieved during the incremental exercise), standardised phosphocreatine and intracellular pH decreased less after training (p < 0.05, repeated measures analysis of variance). The new Borg scale improved significantly after training (p < 0.05). Blood flow did not change significantly in either test.

CONCLUSIONS

In patients with chronic heart failure, localised calf skeletal muscle training improved oxidative capacity without changes in calf blood flow. This training also improved the subjective fatigue scale. This training method may therefore alleviate leg fatigue experienced in daily activities.

Attenuation of unfavorable remodeling by exercise training in postinfarction patients with left ventricular dysfunction: results of the Exercise in Left Ventricular Dysfunction (ELVD) trial

BACKGROUND

Exercise is currently recommended for patients after myocardial infarction; however, the effects of regular exercise on the remodeling process remain to be defined. The aim of this multicenter, randomized study was to investigate whether a long-term physical training program influences left ventricular size and function in postinfarction patients with systolic dysfunction.

METHODS AND RESULTS

Consecutive patients with <40% ejection fraction after a first Q-wave myocardial infarction were randomly assigned to a 6-month exercise training program (n=39) or control group (n=38). After 6 months, a significant increase in work capacity was observed only in the training group (from 4.462+/-1.095 to 5.752+/-1.749 kilopond-meters [Kp-m], P<.01), not in the control group (from 4.375+/-1.143 to 4.388+/-1.199 Kp-m), whereas left ventricular volumes had increased in the control group (end-diastolic volume, from 94+/-26 to 99+/-27 mL/m2, P<.01; end-systolic volume, from 62+/-20 to 67+/-23 mL/m2, P<.01) but not in the training group (end-diastolic volume, from 93+/-28 to 92+/-28 mL/m2, P=NS; end-systolic volume, from 61+/-22 to 57+/-23 mL/m2, P=NS). Conversely, ejection fraction had improved in the training group (from 34+/-5% to 38+/-8%, P<.01) but not in the control group (from 34+/-5% to 33+/-7%, P=NS).

CONCLUSIONS

In postinfarction patients with systolic dysfunction, long-term exercise training may attenuate the unfavorable remodeling response and even improve ventricular function over time.

Predictors of exercise capacity and adaptability to training in patients with coronary artery disease

PURPOSE

Systolic left ventricular dysfunction is a weak predictor of exercise tolerance in patients with chronic congestive heart failure. This study aimed to determine physiologic and other predictors of effort tolerance and adaptability to training in a wide variety of patients with coronary artery disease.

METHODS

One hundred seventy-one patients (group 0) with documented coronary artery disease and various degrees of left ventricular dysfunction were enrolled into a medically supervised exercise training program for 6 months. One hundred six patients had an ejection fraction greater than 50% (group 1), 38 patients between 35% and 50% (group 2), and 27 patients less than 35% (group 3).

RESULTS

Resting parameters of systolic and diastolic left ventricular function did not predict the effort tolerance of patients with coronary artery disease at any level of left ventricular impairment. Noncardiac factors including age, gender, Broca index, and forced vital capacity explained 50% of the variation in peak oxygen uptake in group 0. Peak oxygen uptake, ventilatory threshold, and treadmill time to exhaustion increased significantly after training in all groups. The magnitude of the improvement in these variables was the same for all groups.

CONCLUSIONS

Noncardiac factors were better predictors of the effort tolerance of patients with coronary artery disease than parameters of left ventricular function at entry to an exercise program or after 6 months of training. A similar degree of adaptation to training was seen in all patients regardless of their degree of left ventricular systolic or diastolic dysfunction.

Exercise testing and training of patients with heart failure due to left ventricular systolic dysfunction

Reducing the exercise intolerance and symptoms experienced by patients with chronic heart failure remains an important focus in their clinical care. A clear shortcoming exists; however, with respect to an appreciation that in addition to standard medical therapy, selected patients with stable heart failure also can benefit from a moderate exercise training program. Improvements in central transport, regional blood flow, and skeletal muscle histology and biochemistry all likely account for the increase in exercise capacity and delay in fatigue that these patients experience. Additionally, the autonomic imbalance that is characteristic of these patients is improved. Although the number of patients with heart failure participating in an exercise program is increasing, much work still exists relative to incorporating this treatment method into the care plans established by physicians and physician extenders.

Quality of life and cardiorespiratory function in chronic heart failure: effects of 12 months' aerobic training

OBJECTIVE

To examine the long-term benefits and safety of aerobic training in patients with chronic heart failure.

DESIGN

Non-randomised control trial with 52 weeks follow up.

SETTING

Outpatient cardiac rehabilitation referral centre.

PATIENTS

Patients with compensated chronic heart failure (mean (SD) age 62 (6) years, New York Heart Association stage III, initial resting ejection fraction 22 (7)%). Experimental group of 17 men, 4 women; control group 8 men, 1 woman.

INTERVENTIONS

Experimental group: progressive, supervised aerobic walking programme for 52 weeks.

CONTROL GROUP

standard medical treatment.

MAIN OUTCOME MEASURES

Six-minute walk distance, progressive cycle ergometer test to subjective exhaustion, disease-specific quality of life questionnaire, and standard gamble test, all measured at entry, 4, 8, 12, 16, 26, and 52 weeks.

RESULTS

Control data showed no changes except a small trend to improved emotional function (P = 0.02 at 12 weeks only). Fifteen of the 21 patients completed all 52 weeks of aerobic training; two withdrew for non-cardiac reasons (16, 52 weeks). Three were withdrawn because of worsening cardiac failure unrelated to their exercise participation (4, 4, 8 weeks), and one had a non-fatal cardiac arrest while shopping (16 weeks). Gains of cardiorespiratory function plateaued at 16-26 weeks, with 10-15% improvement in six-minute walk, peak power output, and peak oxygen intake linked to gains in oxygen pulse and ventilatory threshold and reductions in resting heart rate. Marked improvements in quality of life followed a parallel course.

CONCLUSIONS

Aerobic training is safe and beneficial in compensated chronic heart failure. Gains in aerobic function and quality of life persisted over a programme lasting 52 weeks.

Effects of exercise training on left ventricular filling at rest and during exercise in patients with ischemic cardiomyopathy and severe left ventricular systolic dysfunction

The aim of our study was to determine whether exercise training can augment left ventricular diastolic filling at rest and during exercise in patients with ischemic cardiomyopathy and whether any correlation exists between changes in diastolic filling and changes in exercise tolerance. Forty-three consecutive patients (mean age, 54 +/- 8 years) with ischemic cardiomyopathy and severe left ventricular systolic dysfunction (election fraction <30%) were studied. Group T (29 patients) was exercised on a cycle ergometer 3 times a week for 8 weeks at 60% of peak oxygen uptake. Group C (14 patients) was not exercised. All patients underwent an exercise test and a radionuclide ventriculography at baseline and after 8 weeks. At the end, no changes were found in group C. In group T, exercise training increased peak oxygen uptake (1 5%; p < 0.0001), work rate (1 5%; p < 0.005), peak early filling rate (10%; p < 0.02), and peak filling rate (1 1%; p < 0.03). At submaximal exercise, peak filling rate increased at all matched heart rates. The increase in peak filling rate was correlated with the increase in cardiac index (r= 0.72; p < 0.0001) at peak exercise. The independent predictors of the increase in peak oxygen uptake were changes in work capacity and peak early filling rate. The data demonstrate that exercise training can improve the exercise capacity of patients with ischemic cardiomyopathy and severe systolic-dysfunction. The increase in early diastolic filling at rest and during exercise may contribute to the improvement in peak oxygen uptake.

Low intensity exercise training in patients with chronic heart failure

OBJECTIVES

The present study was designed to evaluate whether a specific program of low intensity exercise training may be sufficient to improve the exercise tolerance of patients with chronic heart failure.

BACKGROUND

Recent studies have shown that exercise training can improve exercise tolerance in patients with stable chronic heart failure, mainly through peripheral adaptations. These changes have been observed with exercise regimens at intensities of 70% to 80% of peak oxygen uptake and > 8 weeks.

METHODS

We studied 27 patients (23 men, 4 women; mean [+/- SD] age 57 +/- 6 years) with mild chronic heart failure. We classified patients into two groups: trained group and untrained group. The trained group underwent a low intensity (40% of peak oxygen uptake) training program three times/week for 8 weeks. The untrained group performed no exercise.

RESULTS

An increase in peak oxygen uptake (17%, p < 0.0001), lactic acidosis threshold (20%, p < 0.0002) and peak work load (21%, p < 0.0002) were obtained in the trained group only. Cardiac output and stroke volume were unchanged. A high correlation was found between the increases in peak oxygen uptake and volume density of mitochondria of vastus lateralis muscle (r = 0.77, p < 0.0002).

CONCLUSIONS

Patients with stable chronic heart failure can achieve significant improvement in functional capacity from a low intensity exercise training regimen. The mechanism responsible for this favorable effect involves an increase in mitochondrial density, which reflects an improvement in oxidative capacity of trained skeletal muscles.

Exercise training improves left ventricular diastolic filling in patients with dilated cardiomyopathy. Clinical and prognostic implications

BACKGROUND

Patients with dilated cardiomyopathy (DCM) often have left ventricular (LV) diastolic dysfunction that can precede the development of systolic dysfunction. Recent reports showed that exercise training (ET) improves the exercise capacity of these patients. Although this improvement is primarily due to peripheral adaptations, the contribution of LV diastolic filling has not been well defined. The purpose of this study was to determine whether ET can induce changes in LV diastolic filling that can account for an increase in exercise capacity and whether these changes can influence prognosis.

METHODS AND RESULTS

We prospectively studied 55 consecutive patients (mean age, 55 +/- 7 years) with DCM. Patients were randomized into a training group (36 patients) or a control untrained group (19 patients) and matched for clinical and functional characteristics. All patients underwent a pulsed Doppler echocardiographic study, a radionuclide angiographic study, and a cardiopulmonary exercise test before and after a 2-month ET program. On the basis of the Doppler LV diastolic filling pattern at the beginning of the study, patients were prospectively divided into three subgroups: A (restrictive pattern), B ("normal" pattern), and C (abnormal relaxation pattern). In the trained group, peak VO2 (+12%; P < .0001), peak workload (+8.5%; P < .005), and lactic acidosis threshold (+12%; P < .0001) were significantly increased after training without changes in LV ejection fraction. However, only subgroup C demonstrated significant improvement in peak VO2 (+15%; P < .005). No changes were observed in the untrained group. In the trained subgroups a significant increase in rapid filling fraction (RFF), peak filling rate (PFR), peak early filling velocity (E), and E/A ratio was noted. A significant decrease in atrial filling fraction (AFF), peak atrial filling velocity (A), deceleration time of early filling velocity (EDT), and isovolumic relaxation time (IVRT) was observed only in subgroup C. No changes were found in untrained subgroups. A good correlation was found between Doppler and radionuclide LV diastolic filling parameters before and after training (P < .0001). Multiple stepwise regression analysis demonstrated that pretraining E/A ratio (P < .0001) and peak heart rate (P < .0002) were positive predictors of pretraining peak VO2. Posttraining increase in exercise tolerance (P < .0001) and increase in E/A ratio (P < .0001) were the strongest predictors of an increase in peak VO2. The independent predictors of cardiac events were a greater RFF and a shorter IVRT and EDT. Stepwise logistic regression showed that Doppler LV diastolic filling patterns are independent predictors of overall cardiac events (P = .02), and restrictive pattern has a worse prognosis compared with B (P = .04) and C (P = .007). However, ET did not reach statistical significance (P = .54) as a predictor of cardiac events.

CONCLUSIONS

These data demonstrate that ET induces significant improvement in exercise capacity only in patients with DCM and a pattern of abnormal LV relaxation. The improvement in peak VO2 is significantly correlated with an increase in peak early filling rate and peak filling rate as well as a decrease in atrial filling rate. Doppler echocardiography may be a valuable tool in the prognostic assessment of patients with DCM who will benefit from exercise training.

Effects of exercise training in patients with congestive heart failure: a critical review

Congestive heart failure is a potentially debilitating disorder that affects a significant number of patients. The age-adjusted death rate has doubled over the past decade. Patients live an average of 4 to 5 years, and nearly all suffer from fatigue and breathlessness, which limits exercise capacity and produces a poor quality of life. Patients have usually been advised to avoid exercise because of concerns that they would experience a further decline in cardiac function. However, it has been demonstrated that exercise capacity is not related to the degree of left ventricular systolic dysfunction. This has led to the suggestion that peripheral changes in skeletal muscle and blood supply may play a major role in determining the exercise capacity of patients with congestive heart failure. Studies have demonstrated abnormalities of skeletal muscle blood flow, metabolism and structure, all of which are consistent with the impaired performance observed in these patients. Although the effects of exercise training have been examined in only a relatively few number of patients, the results have been promising. Exercise training has been found to improve exercise capacity and reduce symptoms. However, to our knowledge no data exist as to the impact of exercise training on left ventricular function, hospital stay or mortality in this population. Even though the early results are promising, they require confirmation of feasibility, clinical benefit and safety in larger, long-term randomized trials. It should be determined whether training has a long-term beneficial impact on measures more closely related to daily activities and quality of life. Ultimately, it would be important to determine whether training has an impact on mortality and morbidity.

Long-term physical training and left ventricular remodeling after anterior myocardial infarction: results of the Exercise in Anterior Myocardial Infarction (EAMI) trial. EAMI Study Group

OBJECTIVES

The aim of this multicenter randomized study was to investigate whether long-term physical training would influence left ventricular remodeling after anterior myocardial infarction.

BACKGROUND

Exercise is currently recommended for patients after myocardial infarction; however, the effects of long-term physical training on ventricular size and remodeling still have to be defined.

METHODS

Patients with no contraindications to exercise were studied 4 to 8 weeks after anterior Q wave myocardial infarction and 6 months later by echocardiography at rest and bicycle ergometric testing. After the initial study, patients were randomly allocated to a 6-month exercise training program (n = 49) or a control group (n = 46). A computerized system was used to derive echocardiographic variables of ventricular size, function and topography.

RESULTS

After 6 months, a significant (p < 0.01) increase in work capacity (from 4,596 +/- 1,246 to 5,508 +/- 1,335 kp-m) was observed only in the training group, whereas global ventricular size, regional dilation and shape distortion did not change in either the control or the training group. However, compared with patients with an ejection fraction > 40%, patients with an ejection fraction < or = 40% had more significant (p < 0.001) ventricular enlargement at entry and demonstrated further (p < 0.01) global and regional dilation after 6 months, in both the control and the training group (end-diastolic volume from 77 +/- 14 to 85 +/- 17 ml/m2 in the control group and from 74 +/- 11 to 77 +/- 15 ml/m2 in the training group; regional dilation from 46 +/- 18% to 57 +/- 21% in the control group and from 42 +/- 18% to 44 +/- 26% in the training group). Ventricular size and topography did not change in patients with an ejection fraction > 40%.

CONCLUSIONS

Patients with poor left ventricular function 1 to 2 months after anterior myocardial infarction are prone to further global and regional dilation. Exercise training does not appear to influence this spontaneous deterioration. Thus, postinfarction patients without clinical complications, even those with a large anterior infarction, may benefit from long-term physical training without any additional negative effect on ventricular size and topography.

Randomized 4-week exercise program in patients with impaired left ventricular function

BACKGROUND

This study was designed to determine the controlled effects of a short-term exercise rehabilitation program on patients with moderate-to-severe left ventricular dysfunction after a recent myocardial infarction.

METHODS AND RESULTS

Thirty-nine male patients 51 +/- 8 years old with a large anterior myocardial infarction less than 10 weeks old were recruited for the study. The patients were randomly assigned to either one of two training or control groups on the basis of their resting ejection fraction: training, less than 30%; control, less than 30%; training, 31-50%; or control, 31-50%. Patients were evaluated for filling pressures, radionuclide ventriculography, heart volume, echocardiography, and work capacity. Patients who underwent training participated in an intensive 4-week in-hospital exercise program, whereas the control patients were restricted to a minimal activity program. Results indicated that there were no significant improvements in resting, submaximal, and maximal hemodynamic measurements as a result of the program. Mean work capacity and peak oxygen consumption improved significantly in the less-than-30% training group but was accompanied by a significant increase in mean pulmonary wedge pressure. Resting ejection fraction improved markedly in both less-than-30% training and control patients, but ejection fraction measures were not associated with work capacity. Training did not cause further deterioration in ventricular function.

CONCLUSIONS

It was concluded that in the present study, exercise training had little or no effect on hemodynamic measurements and that the training effects achieved in patients with left ventricular dysfunction are most likely due to corrected impaired vasodilation, not necessarily to cardiac function. The importance of using a control group in this type of study and the wide interindividual variations in training responses are emphasized.

Cardiovascular rehabilitation: status, 1990

Cardiovascular rehabilitation is defined as the process of development and maintenance of a desirable level of physical, social, and psychologic functioning after the onset of a cardiovascular illness. Patient education, counseling, nutritional guidance, and exercise training play prominent roles in the process of rehabilitation. Benefits from cardiac rehabilitation include improved exercise capacity and decreased symptoms of angina pectoris, dyspnea, claudication, and fatigue. Recent pooled data regarding exercise training after myocardial infarction demonstrated a 20 to 25% reduction in mortality and major cardiac events. Exercise training may result in an improvement in systemic oxygen transport, a reduction in the myocardial oxygen requirement for a given amount of external work, and a decrease in the extent of myocardial ischemia during physical activity. The efficacy of modification of risk factors in reducing the progression of coronary artery disease and future morbidity and mortality has been established. Herein we review the history, current practice and results, and future challenges of cardiovascular rehabilitation.