ABC | Volume 114, Nº5, May 2020

Arq Bras Cardiol. 2020; 114(5):943-987 Guidelines Brazilian Cardiovascular Rehabilitation Guideline – 2020 In CVR programs, particular attention should be paid to improving the angina threshold before training begins, which allows greater tolerance to the progression of exercise intensity and, thus, facilitates achievement of the desired beneficial effects. Therefore, the optimization of drug therapy is essential for a safe and effective CVR. Patients engaging in RCV can present a number of physiological adaptations to exercise, including modulation of the autonomic nervous system and reduced HR at baseline and on exertion. Together, these adaptations improve endothelial function and BP reduction, reduce afterload, and improve the diastolic function of the heart. 190 These adaptations can reduce the need for antianginal and antihypertensive agents. It is the role of the rehabilitation physician to discuss adjustments of drug therapy with the patient’s primary physician as necessary. 6.4. Heart Failure Chronic HF is a complex, multisystem syndrome that features dyspnea and progressive exercise intolerance are its core symptoms. Despite recent advances in drug therapy, which have reduced once very high morbidity and mortality rates, symptoms tend to persist, compromising patient quality of life. There is consistent evidence that reduced levels of physical activity in HF trigger a vicious circle that contributes to increasing symptoms and exercise intolerance, secondary to a reduction in functional capacity, producing negative psychological effects, 191 impairment of vasoreactivity, peripheral endothelial dysfunction, 192 and chronic inflammation. 193 In this context, physical exercise has been established as a safe therapeutic strategy that mitigates the effects of progressive physical deconditioning due to the natural course of the disease. 194 Small randomized studies, systematic reviews, and meta- analyzes have consistently demonstrated that regular physical training is safe, increases exercise tolerance, improves quality of life, and reduces hospitalizations in HF. 195-197 A single large, multicenter randomized trial, HF-ACTION, 198 revealed a modest but nonsignificant reduction in primary outcomes (all-cause mortality and all-cause hospitalization), as well as major benefits in quality of life and a reduction in the rate of HF hospitalization. As a weakness of the study, poor adherence to exercise probably impaired the effectiveness of the intervention, a hypothesis that was confirmed later in another study, which demonstrated that adherence is a determining factor for obtaining medium-term benefits. 199 In a systematic review 2 on physical training in patients with HF, which analyzed 33 randomized studies including 4,740 patients (with a predominance of reduced ejection fraction), there was a trend toward reductions in all-cause mortality in the physical exercise group at 1 year of follow‑up. Compared to controls, the physical training group had a lower rate of HF hospitalization and improved quality of life. Regarding benefits in women with HF, the available studies suggest that a positive impact equivalent to that seen in men. 200 For patients with advanced symptoms (NYHA class IV), data are still insufficient to indicate specific exercise programs. A single Brazilian randomized trial tested a daily exercise program on a cycle ergometer combined with noninvasive ventilation. The study evaluated patients hospitalized for acute decompensated HF, and found functional benefits and reduced length of stay. 201 Nevertheless, additional studies are needed to confirm these initial results before a stronger recommendation can be issued. In HF with preserved LVEF, there is recent evidence from small randomized studies and a systematic review showing benefits in VO 2 peak (measured by CPET), 202,203 quality of life, 203,204 and diastolic function (as assessed by echocardiography). 205.206 In light of this evidence, exercise-based CVR is recommended in HF (Table 6) regardless of whether LVEF is preserved or reduced. Public policies must be adopted to ensure that a greater number of eligible patients benefit from treatment in structured CVR programs. 207 Physical exercise alone should not be prescribed for patients with clinically unstable HF, with a clinical picture suggestive of acute myocarditis, or in the presence of acute systemic infection (Class IIIC). 6.4.1. Pre-Exercise Evaluation and Exercise Prescription Internationally, CVR programs are implemented in a wide range of formats, using different exercise modalities alone or in combination. The exercises can include aerobic training (moderate- and/or high-intensity), localized resistance training, and respiratory muscle training (Figure 2). Before starting the training program, it is essential that the patient be clinically stable and on optimized drug therapy; ideally, a functional assessment should be performed, preferably with CPET or a TMET. If the aforementioned functional tests are unavailable, the 6-minute walk test can serve as a parameter for monitoring functional gains. 208 Functional tests should be performed while the patient is on his or her prescribed medications, to mimic the conditions of actual training. The recommended aerobic training can be MICT, which corresponds to the HR zone delimited by the ventilatory thresholds of CPET, or, in the case of a TMET, to the zone located between 60 and 80% of peak HR or 50 and 70% of reserve HR. Patients with more severe disease and greater functional limitations may start at the lower end of the prescription. Intensity can progress up to the upper limit as training advances. Recently, the use of high-intensity aerobic exercises performed in an interval mode – known as high-intensity interval training, or HIIT – has become popular. In this modality, more intense periods of exercise alternate with periods of passive or active recovery, which allows a greater total duration of high‑intensity exercise and, consequently, can increase stimuli for central and peripheral physiological adaptations. In HF patients with reduced LVEF, Wisløff et al. 209 demonstrated that HIIT was superior to MICT in promoting improvement in functional capacity and in different cardiovascular parameters. Subsequently, other clinical trials were carried out and meta-analyzed. The superiority of HIIT over MICT in terms of effects on functional capacity was confirmed in a meta-analysis. 210 The largest multicenter study 960