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Heart failure (HF) is characterized by dyspnea and fatigue leading to exercise intolerance. HF patients have been advised to avoid exercise because of concerns about detrimental cardiac effects. However, in many studies on the effects of exercise training HF patients have demonstrated beneficial outcomes. Furthermore, exercise training has been found to be safe. Recent studies have demonstrated that exercise training might reduce morbidity and mortality. Although these data are promising, confirmation is required from a large clinical trial powered to examine the effects of exercise training on mortality and morbidity. The "Heart Failure - A Controlled Trial Investigating Outcomes of Exercise TraiNing" (HF-ACTION) trial, a large randomized controlled clinical trial, will answer that question. Standardized guidelines for exercise training HF patients have not been established. Exercise training should be individualized according to the results of the exercise test. Ideally, the exercise program should be initiated in the setting of a supervised program followed by a home-based program. Each patient should have a tailored activity program based on a prescription for the frequency of each session, the intensity, duration of each session, and modalities to be used. Exercise training should involve aerobic exercise. Resistance exercise and interval training might be an acceptable method for HF patients; however, more studies are required for these types of exercise programs.

OBJECTIVE: To review therapies for treating patients with heart failure (HF). QUALITY OF EVIDENCE: Recommendations in this paper are mainly based on the results of randomized controlled trials. To a lesser extent, data from smaller, more physiologic studies are included. Where appropriate, recommendations are based on the results of a consensus conference. MAIN MESSAGE: Although pharmacologic therapy is the main strategy for treating HF patients, general measures, such as counseling and advice about regular physical activity, are an important component of management. Use of angiotensin-converting enzyme inhibitors (ACE-I) is central to treating HF patients, because these agents decrease mortality and morbidity significantly. Digoxin does not reduce mortality but does reduce morbidity. Angiotensin II antagonists, although found to provide clinical benefit equal to ACE-I, have not been found as yet to have similar effects on mortality and morbidity. Diuretics and nitrates are useful for treating these patients' symptoms. Calcium channel blockers should generally be avoided. CONCLUSIONS: Angiotensin-converting enzyme inhibitors are the therapy of choice for HF patients and should be used in all cases unless there are contraindications or clear evidence of intolerance. All other therapies are used mainly for symptom relief.

This study was designed to determine 1) whether 12-week oral administration of losartan, an angiotensin II receptor antagonist, in patients with heart failure is well tolerated; and 2) whether functional capacity and clinical status of patients with heart failure in whom treatment with an angiotensin-converting enzyme (ACE) inhibitor is replaced with losartan for 12 weeks will remain similar to that noted in patients in whom treatment with an ACE inhibitor is continued.Losartan is a specific, nonpeptide angiotensin II receptor antagonist. Although specific receptor blockade with losartan has certain theoretic advantages over nonspecific ACE inhibition, definitive demonstration of comparable effects in patients with congestive heart failure is lacking.A double-blind, multicenter, randomized, parallel, enalapril-controlled study was conducted in 116 patients with congestive heart failure (New York Heart Association functional classes II to IV) and left ventricular ejection fractionor = 45% previously treated with stable doses of ACE inhibitors and diuretic agents, with or without concurrent digitalis and other vasodilators. After a baseline exercise period, open-label ACE inhibitors were discontinued, and patients were randomly assigned to 12 weeks of therapy with losartan, 25 mg/day (n = 38); losartan, 50 mg/day (n = 40); or enalapril, 20 mg/day (n = 38). Drug efficacy was evaluated by changes in maximal treadmill exercise time (using a modified Naughton protocol), 6-min walk test, left ventricular ejection fraction and dyspnea-fatigue index. Safety was measured by the incidence of clinical and laboratory adverse experiences.The treadmill exercise time and the 6-min walk test did not change significantly after replacement of ACE inhibitor therapy with losartan. Similarly, a significant change was not observed in either the dyspnea-fatigue index or left ventricular ejection fraction at the end of double-blind period relative to baseline.Losartan was generally well tolerated and comparable to enalapril in terms of exercise tolerance in this short-term (12-week) study of patients with heart failure. The clinical effects of long-term angiotensin II receptor blockade compared with ACE inhibition remain to be studied.

Ion concentrations in whole blood, plasma, and erythrocytes from arterialized venous blood were examined in eight healthy males performing incremental exercise tests to fatigue on an electrically braked cycle ergometer. Exercise was performed during control and low dose (LD) and high dose (HD) of propranolol (beta-blockade). The LD and HD resulted in a significant decrease in peak heart rate compared with control, while peak oxygen uptake during HD was significantly less than either control or LD. Plasma potassium concentration ([K+]) increased significantly during exercise for control, LD, and HD, while LD and HD plasma [K+] were both significantly greater than control. Erythrocyte [K+] increased significantly for control to 119.2 +/- 1.3 mmol/L, for LD to 116.9 +/- 2.0 mmol/L, and for HD to 117.7 +/- 1.2 mmol/L. Plasma lactate concentration ([Lac-]) increased significantly during exercise for control, LD, and HD. Erythrocyte [Lac-] increased significantly for control to 6.4 +/- 0.8 mmol/L, for LD to 6.4 +/- 0.6 mmol/L, and for HD to 5.0 +/- 0.5 mmol/L, with HD [Lac-] less than either control or LD. beta-Blockade did not significantly alter the percent change in mean corpuscular volume (% delta MCV) during exercise. The results indicate that incremental exercise produces an increase in erythrocyte [Lac-] and [K+]. Although beta-blockade increased plasma [K+] at peak exercise, there was no alteration in erythrocyte [K+] response. The treatment did not impair the ability of the erythrocyte to maintain MCV.

During the past decade, research has demonstrated that resistance training is a safe and effective mode of exercise for cardiac patients who are suitable candidates for conventional exercise rehabilitation. Fears of an excessive pressor response seem unwarranted and the incidence of ischaemia is less than that during dynamic exercise such as walking and cycling. Major benefits from resistance training include improved muscular strength, increased peak exercise capacity and submaximal endurance, reduced ratings of perceived exertion during exercise and improved self-efficacy in strength-related tasks. The effects of resistance training on blood pressure and blood lipids levels are equivocal, but there may be positive effects on glucose metabolism. This form of training is likely to assume greater importance in cardiac rehabilitation in the future.

The increase in blood pressure provided by the standard AGSM is caused by both the contraction of the muscles of the lower body and by an increased intrathoracic pressure due to a respiratory straining (Valsalva) maneuver. This study examined the relative effectiveness and fatigability of the two components at +1 Gz and during +Gz acceleration in a human centrifuge. Brachial arterial pressure was recorded from a pressure-tip transducer in six subjects performing isometric leg presses only and on a separate occasion while performing respiratory straining only. Measurements were made over a range of intensities for the leg press contractions and Valsalva maneuvers and were conducted at +1 Gz and during slow and rapid onset runs up to +5 Gz in a human centrifuge. Blood pressure was also recorded during pulsing or intermittent contractions of the legs. We found it difficult to completely separate the blood pressure response to the leg press component from that of the respiratory straining alone component, since a moderate respiratory straining maneuver usually accompanied forceful contractions of the legs. We conclude, however, that a major portion of the elevation in blood pressure caused by the AGSM can be attributed to contraction of the muscles of the lower body and that this component is less fatiguing than the respiratory straining component. At +1 Gz a pulsing isometric contraction of the legs was no more effective in elevating blood pressure than a constant isometric contraction over the same duration.

Reactive hyperemia responses (RHR) of various magnitudes were obtained after release of a brief occlusion in six of 10 coronary bypass grafts. All of the vein grafts responded to an injection of sodium nitroprusside (50 microgram) directly into the open graft with an increase in blood flow that was always greater than the flow recorded after release of the occlusion. This response indicates that there were no flow-limiting stenoses and that the distal vascular beds were responsive to vasodilator stimuli. RHR's, expressed as percent repayment of calculated flow debt, were correlated significantly (r = 0.96, p less than 0.01) with the magnitude of the decrease in vein graft pressure measured during occlusion of the graft. It is suggested that the decrease in pressure is related to the amount of blood flow from alternate sources to the vascular bed during occlusion of the graft, and that this collateral flow is an important determinant of the magnitude of RHR in bypass grafts.

Cardiopulmonary exercise testing is an objective method of assessing the functional capacity of a patient. In contrast to clinical assessment and resting investigations, exercise testing is useful in detecting early changes in patients with cardiac or respiratory disease. Although a number of different types of ergometers can be used for testing, the ones used commonly are the cycle and treadmill. Comparison of these two modes of exercise shows no significant clinical difference between them; therefore, either can be used for routine cardiopulmonary exercise testing. There are various types of exercise protocols, but generally the protocol should involve large muscle groups and should be tolerated by the population being tested. The main goal when selecting an exercise protocol is to strike a balance between workload increments that do not prematurely fatigue the subject and at the same time allow the subject to reach a maximum power output within 8 to 15 minutes. Whatever the exercise test protocol used, the intensity should be increased to a symptom-limited maximum. This procedure is safe as long as contraindications for starting a test and indications for terminating a test are adhered to strictly. The assessment of cardiorespiratory responses during exercise ranges from simple and noninvasive techniques to those that are invasive and complex. In the majority of cases all the information needed for proper assessment of the patient can be acquired with simple noninvasive techniques.