ABC | Volume 114, Nº5, May 2020

Arq Bras Cardiol. 2020; 114(5):943-987 Guidelines Brazilian Cardiovascular Rehabilitation Guideline – 2020 6.4.2. Final Considerations on Heart Failure Given the variety of benefits observed, it is essential that patients with HF perform physical exercises regularly. Ideally, this should be done in the context of a CVR program, with an individualized prescription combining moderate- and/or high-intensity aerobic training, localized muscle resistance exercises, and respiratory muscle training, depending on the patient’s clinical condition and functional limitations, and according to patient preferences and staff experience. In addition, there are valid alternatives even for very debilitated and severely deconditioned patients. 214,217 6.5. Heart Transplantation Heart transplantation (HTx) is the treatment of choice for patients with refractory HF, whose symptoms remain severe despite use of the entire pharmacotherapeutic arsenal and surgical procedures as indicated. In recent years, there have been significant advances in HTx, with the emergence of new surgical techniques and the development of more efficient immunosuppressants. In Brazil, there has been substantial growth in the number of procedures, which had been stagnant since 2015, with a rate of 1.7 transplants per million population (pmp). In 2019, the rate grew 17.6%, reaching 2 transplants pmp, very close to the target set for the year (2.1 pmp). In 2018, 357 procedures were performed, and by March 2019, 104 hearts had been transplanted in Brazil. 218 HTx aims to improve quality of life, as well as survival, in this population. 219,220 Recipients are able to return to work and lead normal lives with minimal or no symptoms. 221 The survival rate is estimated at 90% at 1 year and around 70% at 5 years. 222 Although HTx significantly improves patients’ functional capacity, VO 2 peak is still reduced when compared to that of healthy, age-matched individuals. 223,224 Among other factors, this can be explained by: 1) in the immediate post-transplant period, the allograft is devoid of sympathetic and parasympathetic innervation (autonomic denervation), causing an increase in resting HR, attenuating its natural elevation in response to exercise, and impairing recovery after exertion 224,225 ; 2 ) patients often exhibit skeletal muscle dysfunction (sometimes to the point of cachexia), in which immunosuppressive therapy and pre-transplant HF play prominent roles 226 ; and 3) impairment of vascular and diastolic function. 227 During the acute phase of exercise, the increase in cardiac output of HTx recipients depends fundamentally on the Frank–Starling mechanism, i.e., on increase in venous return, inotropy, chronotropy, and reduction in afterload. 228,229 In addition, there is an increase in the concentrations of circulating catecholamines, 227 which decrease slowly after the end of exercise, explaining the slow recovery of HR in these patients. 230 Immunosuppression may predispose HTx recipients to a higher risk of other complications, 231 and these patients may develop HTN, diabetes mellitus, and CAD. 232 Conversely, physical exercise is known to be an excellent therapy for management of these chronic diseases 93,233 and is effective in optimizing autonomic control. 230,234 Physical training after HTx contributes to an increase in VO 2 peak and improvements in hemodynamic control, muscle strength, and bone mineral density, 233-236 thus improving prognosis. 19 Although there are countless possibilities for training prescription, the recommended method remains aerobic exercise, which can be performed continuously or, in specific cases, at intervals and at different intensities, 170 combined with resistance training whenever possible. 6 6.5.1. Benefits of Physical Exercise In a pioneering study by Richard et al., 237 the investigators found that, 46 months after HTx, patients who underwent aerobic training had a functional capacity and chronotropic function similar to those of healthy individuals. Previous studies had already demonstrated the safety of physical training in this population. 234,238-240 A Cochrane meta-analysis of nine randomized clinical trials, including 284 patients, compared the effect of physical training to usual care in the post-HTx setting. 234 An average increase in VO 2 peak of 2.5 ml.kg -1 .min -1 was observed in those who received training versus those allocated to usual care. Rosenbaum et al. 241 assessed the relationship between early participation in a CVR program after HTx and found that the number of sessions performed in the first 90 days was directly associated with better 10-year survival. Haykowsky et al. 242 described significant improvements in VO 2 peak of HTx recipients, with an average increase of 3.1 ml.kg -1 .min -1 after 12 weeks of combined training (resistance and aerobic). Kobashigawa et al. 243 studied 27 patients after HTx who received a combination of aerobic, resistance, and flexibility training for 6 months versus a control group. The duration and intensity of the aerobic exercise sessions had a goal of at least 30 minutes of continuous, moderate exercise on a cycle ergometer. The intervention group showed an average increase of 4.4 ml -1 .kg -1 .min in VO 2 peak, versus 1.9 ml.kg - 1 .min -1 in the control group. These data provide valuable information on the importance of both types of training for this population. Regarding high-intensity training in patients after HTx, the number of studies is still small, but the results obtained have been encouraging. In a crossover study, Dall et al. 244 found a greater effect of HIIT compared to MICT on VO 2 peak, with an additional gain of 2.3ml.kg - 1 .min -1 and superior improvement in quality of life. One meta-analysis 233 included three randomized controlled trials that compared HIIT (intense blocks: 80 to 100% of VO 2 peak or 85 to 95% of peak HR) to usual care. Post-HTx patients randomized to HIIT showed an increase in VO 2 peak of 4.45 ml.kg -1 .min -1 after the intervention period, which ranged from 8 to 12 weeks of three to five weekly sessions. Nytrøen et al. 224 evaluated the effects of a HIIT program compared to a control group in 43 HTx recipients. The authors evaluated the progression of allograft vasculopathy, assessed by intravascular ultrasound, and found less progression of atheromatous plaque in the HIIT group. However, additional studies are still needed to elucidate these benefits. 245 Some well-known common adverse effects of the use of glucocorticoids after HTx are muscle atrophy and weakness. In 1998, Braith et al. 235 were the first to study the effect of resistance training on glucocorticoid-induced myopathy in HTx recipients. One group received training and was compared with a control group. After 6 months, although both groups had increased muscle strength in the quadriceps and lumbar extensors, the increase was up to six times greater in the training group. 962