The Benefit Of Exercises In Cardiac Rehabilitation Nursing Essay

A study published in the Journal of Clinical Nurse in USA shows the importance of a lifestyle approach in the maintenance of secondary risk factors and especially physical activity, but unfortunately very little evidence exists, on the long-term adherence, to these programmes. An increase in physical activity and exercise is known to have an independent benefit, associated with reduced mortality and morbidity (Jolliffe et al. 2004) and is a primary objective of all cardiac rehabilitation programmes (USA, Department of Health 2000). The mechanisms underpinning the observed cardiac rehabilitation benefit could, theoretically, be attributed to an increase in physical activity status (Schairer et al. 1998, Thompson et al. 2003), however, further analysis suggests that this may not be as straightforward, as it first seems. Although each patient showed significant positive gains from rehabilitation, the effect was not evident, to the same extent, in all outcome measures, for each patient. For instance, the correlation between depression and MacNew Health-Related Quality of Life explained, 79% of the variance at 12 months, yet the same correlations with total energy expenditure only explained 5% of the variance, in the same time. The benefits gained from six-week cardiac rehabilitation, seen in the form of improved quality of life and reduced anxiety and depression, may not be explained by significant changes in physical activity.

• Heart Failure

After a Myocardial Infarction, the heart is so severally damaged that it is unable to generate sufficient force, to pump enough blood to keep the body alive, & as a result the patient goes into cardiogenetic shock. Whenever the left ventricle becomes dysfunctional, the heart becomes progressively weaker. Myocardial Infarction is by far, the most common cause of left ventricular dysfunction, & as a result the ejection fraction, is reduced to less than 50%. Other causes of this include: Chronic Hypertension, Valve diseases, school abuse and cardiomyopathy.

Following myocardial infarction, the reduction in stroke volume is due to impairment of both the filling and emptying phases of the left ventricle. Filling is reduced because damage to the left ventricle makes it less compliant and, consequently cannot accommodate the same volume of blood that a healthy heart can. This results in reduced preload and therefore, a reduction in stroke volume. Emptying is impaired because the loss of cardiac muscle mass (as a result of the infarction) reduces contractility and, consequently, a lower percentage of blood is ejected.

If the infarct is extensive or the site of the myocardial infarction is anterior, then the left ventricle becomes bigger and thicker (a process known as remodelling) which initially helps to maintain cardiac output. Nevertheless, such compensatory mechanisms, although designed to support cardiac function, will over time, actually increase the work of the heart. For example, increased sympathetic activity raises blood pressure, which means the heart has to work harder in order to eject blood into the systemic circulation.

Once the compensatory mechanisms cease to be effective, left ventricle dysfunction typically progresses to a situation in which symptoms of heart failure becomes apparent.

Heart Failure occurs when the left ventricle is unable to maintain a cardiac output that is adequate to meet the oxygen demands of the body. Clinically heart failure is a syndrome in which patients have symptoms of breathlessness or fatigue, either at rest or during exertion. They may also experience ankle swelling. The right ventricle therefore ejects less blood causing blood to back up in the systemic circulation phase which in turn increases the pressure in the systemic capillaries. The result is, fluid leaks from the circulation into the tissues resulting in pitting oedema (swollen tissue in which indentation can be made, usually seen as swollen ankles). When the left-side fails, the reduced ejection fraction of the left ventricle causes blood to back up in the pulmonary capillaries. The result is, fluid leaks from the circulation into the tissues, hindering the gaseous exchange process, particularly on exertion.

Patients complain of fatigue, their exercise capacity is reduced and usually they notice deterioration, in quality of life. The degree of the left ventricular impairment has an effect on the survival rate; the worse the impairment, the lower the survival. The chances of heart failure, increase, with the average age being 75years. Half of all patients diagnosed with heart failure, will die within 4 years, and over 50% of those patients with severe heart failure will die within 1 year (ECS Guidelines, 2006).

Cardiac rehabilitation is a really important mechanisms to improve and prolong life for patients with Heart Failure, Endurance training improves symptoms and quality of life and decreases mortality rate and hospitalization, and also being recognised as a benefit for heart failure (HF) patients It has also been proven that endurance training benefits the cardiac and skeletal muscle oxidative metabolism and intracellular energy transfer in HF.

A studied published in the Cardiovascular Research Magazine, titled "Beneficial effects of endurance training on cardiac and skeletal muscle energy metabolism in heart failure" showed how the exercises can improve the life of patients diagnosed with heart failure.

The studied showed that heart failure induces a metabolic myopathy, affecting both heart and skeletal muscles. This manifests itself, mainly, by decreased oxidative capacity, shift in substrate utilization and altered energy transfer by phosphotransfer kinases. In skeletal muscle, endurance exercise capacity is mainly conditioned by increased oxidative capacity, increased lipid utilization, improvement of energy fluxes and a better relationship between energy production and utilization. Prolonged exercise is thus able to counteract these deteriorations, by improving oxygen and substrate delivery, as well as facilitating a metabolic remodelling of the cardiac and skeletal muscles. Although beneficial effects of endurance training in heart failure are indubitable, further work is needed to delineate the pleiotropic effects of physical activity on cardiac and skeletal muscle functions. This issue is of interest for clinical output, especially for rehabilitation of patients with heart failure. It is important one knows the beneficial effects of endurance training in CHF patients in terms of exercise capacity, quality of life and even morbi-mortality(Cardiovascular Research 73 – 2007)

There is increased evidence that no harm is done to the heart by endurance training, only benefits. If by further studies this proves to be true in human patients, training should be implemented in the care standards, together with β-blockers and medication antagonizing the renin–angiotensine–aldosterone system. Further research, examining the mechanisms of these beneficial effects, on the whole organ and cellular levels ,will be of vital importance, in order to identify potential advantageous effects of pharmacological and physical therapy .

Chapter 3 – Methodology:

The long-term association between Cardiovascular Rehabilitation attendance and mortality has been rarely studied. A randomised controlled trial of 651 men, with AMI attending an exercise-only programme in the USA, found no difference, in all causes of mortality at 19 years (Cardiopulm Rehabil Prev 2000; 20:130). Conversely, a Swedish observational study of 305 men and women after Myocardial Infarction, found that attendance at Cardiovascular Rehabilitation was associated with a reduction in all-causes of mortality (37% vs. 48%) after 10 years, but not after 5 years (Eur Heart J 1993;14:831–5), These were earlier studies (in the 1970s) ,but since then outcomes might have been influenced by the changes in medical management that occurred during the 1980s and early 1990s, such as the introduction of β blockers in 1985 and of ACE inhibitors and statins in 1994–5. No contemporary studies have investigated the effects of Cardiac Rehabilitation, on the mortality rate in patients, with combined Myocardial Infarction, Coronary Artery Bypass Gravity Surgery and Percutanes Coronary Intervention, over a period of 10 years or more. However, an Australian Study done by the Heart Research Centre in Melbourne and published in the heart Magazine in December 2012, was the first study to do so ,and indicated that Cardiac Rehabilitation may have a sustained benefit on mortality.

The main finding from this study was that after a 14-year follow-up period, Cardiovascular Rehabilitation non-attendees had a higher risk of mortality, than those who did attend Cardiovascular Rehabilitation, even after taking into account baseline differences between groups. We also found a significant agenda sex-adjusted dose–response relationship between the proportion of sessions attended and all-cause mortality. This association became non-significant after further adjustment for baseline differences in those who smoked.

The study brings a crude all-cause mortality rates and attendance at Cardiac Rehabilitation, there were 199 deaths during a median follow up time of 14.2 years. Crude (unadjusted) all-cause mortality rates of attenders and non-attenders are shown in table 2. Among the total study population, nonattenders had a mortality rate per 10 000 person years which was nearly double that of attenders. A similar trend was seen for oth men and women, for those aged over 60 years at study baseline and for patients with Acute Myocardial Infarction or Coronary Artery Bypass Graft Surgery.

Crude all-cause death rates per 10000 person-years for attenders and non-attenders at a cardiac rehabilitation programme; overall and by subgroups:

Attenders* Non-attenders†

No of

deaths‡ Death rate per

10000 person-years

(95% CI)§ No of

deaths‡ Death rate per

10000 person-years

(95% CI)§

Total

(n=544)

76 210 (168 to 263) 123 429 (359 to 512)

Men

(n=397) 54 193 (148 to 252) 78 373 (299 to 465)

Women

(n=145)

22 270 (178 to 411) 45 579 (433 to 776)

Baseline age in years

≤49

(n=83) 5 76 (32 to 182) 4 84 (32 to 225)

50–59

(n=129)

8 84 (42 to 168) 10 127 (68 to 236)

60–69

(n=170)

29 208 (145 to 300) 29 388 (269 to 558)

≥70

(n=160)

34 558 (399 to 781) 80 930 (747 to 1158)

Coronary Artery Bypass Graft

(n=155)

25 182 (123 to 270) 24 410 (275 to 611)

Acute Myocardial Infarction

(n=295)

44 225 (168 to 303) 75 523 (417 to 655)

Percutaneous Coronary Intervention (n=92) 7 242 (115 to 507) 24 283 (190 to 422)

Chapter 4 - Analysis of Results/Findings:

The sample study done by The Heart Research Centre in Melbourne was drawn from 652 participants, recruited for an earlier study, investigating attendance patterns after referral to Cardiac Rehabilitation. Subjects for the original attendance patterns study were patients with Acute Myocardial Infarction, Coronary Artery Bypass Graft Surgery or Percutoneous coronary Intervention, who were consecutively admitted over an 11-month period, during 1996 and 1997 to one of two major teaching hospitals in Melbourne. In Victoria the prevailing policy of automatic referral to Cardiac Rehabilitation, was that, all patients were encouraged to attend a Cardiac Rehabilitation programme. at various hospitals. Participants were then tracked for 4 months after their acute event, to determine their Cardiac Rehabilitation attendance. This subsequent follow-up study used a retrospective cohort design, to examine long-term mortality outcomes on the participants that were enrolled, in the original attendance patterns study. That being, the 573 patients whose Cardiac Rehabilitation attendance was successfully determined. Allowing for disease severity and avoiding survival bias, 12 participants died within 1 year of their cardiac event and a further 17 had inadequate CR attendance records. This left 544 subjects (83.4% of the 652 patients in the original attendance patterns study) available for follow-up mortality study.

Chapter 5 - Discussion of Results

The study showed really interesting results. First a total of 281 (52%) men and women attended at least one exercise session. There were no significant statistical differences seen between attendees and non-attenders. Comparing those who did not attend any sessions; attendees were more likely to be male, younger, and having undergone Coronary Artery Bypass Graft Surgery. Attenders were also more likely to be employed and have a family history of heart disease, but were less likely to report having diabetes, than non-attendees. It also examined the characteristics of the participants excluded. The 17 patients with inadequate CR records, were more likely to have had an AMI, (p=0.007), while the 12 participants who died within 12 months of their event ,were also more likely to have had an Acute Myocardial Infarction, but also be unemployed, live alone, have left school earlier (p=0.015) and have diabetes.

The most important findings of this Australian study were consistent with many meta-analyses and systematic reviews. All reporting significant reductions in all-cause mortality, following attendance at comprehensive Cardiac Rehabilitation programmes. This study showed a reduction in mortality, of between was 20% and 32% for Cardiovascular Rehabilitation attendees. These meta-analyses and systematic reviews were predominantly based on smaller trials (dating from the 1970s) and were confined to younger men after Acute Myocardial Infarction. They excluded women, older patients and other diagnostic groups, which were more reflective of a target group for Cardiovascular Rehabilitation. More recent studies, which have tended to include these patient subgroups, show that there is a 50% reduction in mortality as a result of Cardiac Rehabilitation. This is much more, consistent with the 58% reduction reported by the Australian Study. On the other hand a Canadian matched cohort study, using registry-based data, found a 50% reduction in mortality rates at 5 years after beginning Cardiac Rehabilitation attendance, while a study of 2396 Percutaneus Coronary Intervention patients, found a 47% reduction in mortality rates at 12 months, after starting Cardiac Rehabilitation attendance (Circulation 2011;123:2344–52)

All contemporary studies have demonstrated a beneficial effect of Cardiac Rehabilitation on mortality rates. However, two systematic reviews, comparing Cardiac Rehabilitation attendance and the reduction in mortality ,found no significant association in subgroup analyses of studies published ,after 1995 (Am J Med 2004;116:682–92) In both sub analyses, there was only a small amount of studies included, and the populations chosen were limited to younger male patients with Acute Myocardial Infarction, thus significantly reducing the results.. The recent Rehabilitation After Myocardial Infarction Trial (RAMIT) from the UK found no effect of Cardiovascular Rehabilitation attendance on all-cause mortality,19 although the study methodology has been criticised (Heart 2012;98:672–3).

Findings from RAMIT have led to suggestions that comprehensive CR may no longer be relevant, when you consider high effective treatments, such as β blockers, statins and early revascularisation (Heart 2011; 98:637–44). However, others suggest that the RAMIT findings demonstrate, that the type of CR performed in the late 1990s in the UK, was not as effective and was deemed as being " not fit for purpose’(Heart 2012;98:605–6.). The UK model of Cardiovascular Rehabilitation is very similar to the Australian model described in our study. However, recent recommendations for CR in both countries, encourages a more comprehensive approach, by looking at funding, staffing, referral and attendance rate issues. All of these will continue to affect the optimal delivery of Cardiovascular Rehabilitation.

A further question remains about the continuing need for Cardiovascular Rehabilitation, in light of the reduction in Cardiac Heart Diseases related deaths, over the past few decades. Recent evidence shows, that this decline is slowing, especially among people aged <55 years (Heart 2008; 94:178–81). This pattern may be due to an increased risk of diabetes and obesity in this age group, both of which are major risk contributors to Cardiac Heart Diseases (Lancet 2004; 364:937–52). United Kindon studies exploring the changing clinical profile of Cardiac Rehabilitation attenders between the 1990s and 2006, found that, while there was a very large increase in statin use, as well as a subsequent improvement in lipid parameters, participants were now more commonly diagnosed with diabetes and were more likely to be obese (J Cardiopulm Rehabil Prev 2008;28:299–306). This trend suggests that there will be a continuing need for interventions such as Cardiac Rehabilitation.

Chapter 6 - Conclusion:

Although the short-term benefits of Cardiac Rehabilitation on risk factors are clear (with risk factor reductions accounting for about half the reduction in mortality, associated with CR), further research is required , as to what the long term benefits of Cardiac Rehabilitation has on risk factors. CHD progresses over several years, and therefore long-term follow-up of patients with CHD; will provide valuable evidence, for compiling strategies that will slow the progression of the disease. The beneficial effects of Cardiac Rehabilitation will be further substantiated by these findings

Evidence for the benefits of comprehensive Cardiac Rehabilitation programmes is strong and research should now focus on the ‘gaps’. There needs to be a system of referral, which will encourage patients to participate in Cardiac Rehabilitation, as well as developing strategies, to enhance patient retention, particularly among those population groups who do not attend CR, such as smokers, women and younger patients. Investigators should also continue to produce evidence for alternative models of cardiac secondary prevention, so that patients can choose from a range of options.

Observational studies need to be undertaken using larger samples, from a variety of populations and countries. Such studies might identify predictors of ‘successful’ Cardiac Rehabilitation programmes,

and they also might allow for subgroup analysis. An example of this would be, stratification of outcomes by socioeconomic status, in order to assess the potential impact of CR on health inequalities. Collection of appropriate baseline data would also allow for exploration of the mechanisms by which CR confers long-term benefit.

Recent worldwide studies provide further support, for the long-term benefits of Cardiac Rehabilitation in a contemporary, heterogeneous population. We should continue to recognise, that comprehensive models of Cardiac Rehabilitation, have significant health benefits. When you look at the projected increase in obesity, diabetes and their impact on CHD, the need for Cardiac Rehabilitation, as an effective intervention, is crucial, if we are to keep the mortality rates down.

In conclusion the study highlighted some of the benefits patients receive through Cardiac Rehabilitation but also show how it is harder for patients with a Cardiac event to achieve the same level of results as their non cardiac event counterparts from the Rehabilitation programme.

All those points reinforce the importance of Cardiac rehabilitation. Studies carried out all over the world prove the benefits of these programmes but unfortunately a huge number of patients still drop out of the rehabilitation programme before the conclusion. Sadly there are an even greater percentage of patients that do not make physical exercise a lifestyle habit and relapse into another Cardiac Event.

Governments are spending millions on rehabilitation programmes but Health and Fitness professionals should also develop a better understand of the principles and of Cardiac Rehabilitation as in this area where they can literally save lives.