Physical Rehabilitation (Treatment Strategies in Cardiac Transplantation) Part 2

Exercise program in heart transplanted patients

Regular physical activity has played important role in the improvement of quality, as demonstrated in studies because regular physical activity may revert or diminish the physiological alterations in transplanted patients (Fig.9 ) (Guimaraes, 2004).

Association between physical capacity and heart transplantation and the potential role of physical training on the systemic improvement, on the physiopathological effect, on quality of life and on functional capacity

Fig. 9. Association between physical capacity and heart transplantation and the potential role of physical training on the systemic improvement, on the physiopathological effect, on quality of life and on functional capacity

Exercise in ICU (intensive care unit)

Even in the earliest days after surgery, the physical therapist will begin to work. Exercise in this scenario is important for several reasons. It aims to restore pulmonary capacity once a median sternotomy procedure is performed and can cause diaphragm reflex inhibition, pain whenever breathing. It also looks for reducing chances of getting lung infections, thromboembolism, bedsores and decrements in peak oxygen consumption (VO2peak) and related cardiovascular parameters (which may regress approximately 26% within the first 1 to 3 weeks of sustained bed rest) (Braith, 2000) .

Types of exercise include respiratory ones, either with or without equipments, exercises in bed, changing positions in bed, sitting, standing and walking.

Recipients remain in hospital post-transplant depending on their general improvement and lack of complication. Different from pretransplantation hospitalization, which may be prolonged for inotropic support or a ventricular assist device, they leave hospitals soon after surgery because of the risk of infection in a hospital (usually after 2 weeks if there aren’t any complications) and are discharged from the unit to a rehabilitation program.

Exercise prescription

After heart transplantation patients show physical deconditioning, muscular atrophy, weakness and lower maximal aerobic capacity so regular aerobic/strength training have been studied in both post-heart transplant recipients adults (Keteyian, 1991) and children (Patel, 2008) to study whether it would improve exercise performance. Most programs currently treating orthotopic transplant patients usually provide 6-12 week of exercise training.

In general overview, exercise program improves maximal O2 consumption and, by improving peak heart rate and also improves O2 delivery in adults after a 10-week exercise program (Keteyian, 1991).

Benefits have also been found in children. After an exercise intervention consisted of aerobic exercise (either running or bicycling for 30 minutes three days/week), plus strength training was performed with elastic bands to specifically exercise biceps and triceps groups for 15-20 min/session was responsible for pediatric heart recipients improvement in their endurance time, peak oxygen consumption and strength.

Studies on aerobic training after cardiac transplantation have distinct characteristics of intensity, type, duration and frequency, so that the evaluation of the results on the effects on the cardiovascular system should be interpreted carefully. Moreover, the intensity of the exercise may enable or help to depress the immune system by hormonal, metabolic and mechanical mechanisms; however, there are no studies about the effect of intensity on the immune response in this population. (Guimaraes, 1999).

Knowing the exercise stress tests is necessary information in order to develop a correct exercise prescription. Naughton protocol is more recommended for these patients. Among the parameters, heart rate reflects the cardiac stress, and the rest and maximum, or the metabolic thresholds are used to prescribe the range of exercise intensity and monitor physical training (initially 70% heart rate reserve). (Carvalho, 2009a; Braith, 2000).

Blood pressure during exercise reflects a combination of increased cardiac output and reduced peripheral resistance, thus it should also be considered when prescribing exercise and monitoring it. These hemodynamic variables must be observed during the rehabilitation program for either progression or discontinuation, if necessary.

Physical exercise after hospital discharge

Nine months after the surgery procedure, partial reinnervation shows up, but it, yet, promotes inefficient control of heart rate (Bernardini, 1998). This reinnervation can be partially restored over the years. Although heart rate increases after an exercise program (Schwaiblmair, 1999), it remains attenuated, thus, not worth to precise monitor cardiovascular and aerobic exercise prescription. Around 80% of the maximum age-adjusted value could be considered an effort near the maximum, so, it may be a parameter for prescribing exercise (Carvalho, 2009a).

Another good method to prescribe aerobic exercise training in heart transplant recipients without a cardiopulmonary exercise test with gas analysis is by the ratings of perceived exertion (Carvalho, 2009b). In order to achieve this purpose subjects are encouraged to do exercise between a relatively easy rhythm and a slightly tiring one, between 11 and 13 on the Borg Scale as seen in Table 1. (Guimaraes, 2008).

Borg Scale

Self-subject fatigue association

6

7

Very easy

8

9

Easy

10

11

Relatively easy

12

13

Slightly tiring

14

15

Tiring

16

17

Very tiring

18

19

Exhaustive

20

Table 1. Borg Scale of subject fatigue.

Comparing heart transplant recipients from our lab at Heart Failure Clinics of Heart Institute before and after an exercise program, a more efficient parasympathetic response can be identified (compare the blue line on Figure 3 to the one in Figure 10). In sedentary people after transplantation exercise recovery is significantly slower than in healthy ones (Figure 1), but it becomes close to normal after exercise (Figure 2). This may be explained by the partial restoring function of the autonomic nervous system (ANS), especially of the parasympathetic system because a more efficient stimulation in concern of a reduction in heart rate becomes present.

Specific time exercise program is, yet, not precise in order to restore ANS due to total reinnervation, but current data indicates that combined therapy (drug stimulation of reinnervating sympathetic neurons and exercise) can establish better ANS function after orthotopic heart transplantation (Burke, 1995).

Published studies on heart transplant recipients’ rehabilitation have shown better hemodynamic function (Braith, 1998b) with dif\ferent training programs. It is clear that physical activity immediately following heart transplantation and adherence to an individualized program that promotes an active life style helps to restore cardiovascular function (Goodman, 2007). Programs include aerobic exercise, weightlifting, flexibility exercise, or training in both land and water.

HR representation after a 12-week exercise program in a healthy subject (in red) and in a heart transplantation recipient (in blue).

Fig. 10. HR representation after a 12-week exercise program in a healthy subject (in red) and in a heart transplantation recipient (in blue).

Each of the programs has a particularity. Their specifications and attention are concerned to type of exercise, intensity, volume and frequency of the sections. Knowing these differences may help one to better prescribe a training exercise program (Table 2.)

Aerobic exercise

Aerobic exercise such as walking, running and cycle ergometer can be prescribed on a continuous or interval kind, depending on experience or protocol used by rehabilitation service. Nonetheless, the intensity of aerobic exercise should be determined according to the workload, if possible at the respiratory compensation point reached during the cardiopulmonary exercise test in combination to exercise at a pace between "relatively easy and slightly tiring", between 11 and 13 on the Borg Scale (Guimaraes, 2008). Exercise sessions should be held three times a week with a 5-minute warm up, 30 minutes of aerobic training followed by 5 minutes of recovery and 20 minutes of strength exercises.

Weightlifting

Exercise with weights, adjacent to the aerobic exercises, have been recommended after heart transplantation, although hemodynamic function is restored to near normal values, this group of patients still shows a significant decrease in muscle mass and strength, bone rarefaction and histochemical changes in muscle fiber type from type I to type II (Braith, 1998; Lindenfeld, 2004a, Lindenfeld, 2004b).

These persistent changes in the transplant can be minimized with regular practice of resistance training with weights and moderate intensity that must be performed in small series, with a maximum of ten repetitions for flexors and extensors groups of the upper and lower limbs. This results in reduction of osteoporosis and skeletal muscle myopathies (caused by the use of glucocorticoids), and contributes to the gain in muscle strength and increase in VO2 peak, at the same time (Lindenfeld, 2004b).

Specification

Aerobic

Weightlifting

Flexibility

Water

Static

Dynamic

Type

Interval and continuous training

Main muscle groups

8 to 10 (main muscle groups)

Main muscle groups

Walking (in hot water at 30 or 310C)

Intensity?

60% to 70% peak

VO2 HR between AT and RCP

30 to 75%MVC

40% to 80% 1MR

light to moderate

60% to 70% peak VO2 HR between AT and RCP

Volume’

30 to 40 min

1 to 10 x 6 s

1 x 4 to 6 (avoiding fatigue)

3 a 5 repetitions

30 a 40 min

Frequency

5 x a week

2 x a week-1 (5 – 10 x a day)§

2 x a week (maximal)

5 x a week

2 x a week

Progression

Respect the Borg scale perception between 13 and 15

Tolerable ROM (initial); Perform contraction under different

ROM whenever pain

and inflammation get lower. Add load when strength is increased

5-10%-load (a week) •

In order to stretch soft tissue and either to keep or increase ROM

Respect the Borg scale between 13 and 15

Attention

BP lowering during exercise

sections whenever Borg scale perception is greater than previous sections.

Contraction > 10 s may increase BP

-

Respect morphologic al limits in order not to cause injuries.

BP lowering during exercise sections whenever Borg scale perception is greater than previous sections.

Table 2. Practical recommendations for exercise prescription. MVC: maximal voluntary contraction; AT: anaerobic threshold; RCP: respiratory compensation point; 1MR: one maximal repetition test; ROM: range of motion; BP: blood pressure; T Subjects were encouraged to begin under their low threshold and increase intensity up to their highest threshold, progressively, as tolerated. ‘ Static: 1) from a 6-second contraction at first, to an 8 or 10-second contraction, 2) wait 20-second intermission between contractions; Dynamic: one series of 4 or 6 repetitions without any muscle fatigue; §subjects should go from exercising twice a day to 5-10 times a day.

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