LITERATURE REVIEW: EFFECTIVENESS OF CARDIAC REHABILITATION IN PATIENTS WITH CORONARY HEART DISEASE

Background: Cardiac rehabilitation is an evidence-based intervention that includes physical exercise, health education, and modification of health behavior in patients with cardiovascular disease. Cardiac rehabilitation is considered as secondary prevention after acute coronary syndrome and improves treatment outcomes in patients with coronary heart disease. This literature review aimed to evaluate the effectiveness of cardiac rehabilitation in coronary heart disease patients. Methods: This present study was a literature review discussing cardiac rehabilitation for coronary heart disease patients. Results: The result showed that the functional capacity of the CR group was more increased compared to non-CR (p <0.001; α <0.05), left ventricular ejection fraction (LVEF) significantly increased in the CR group (p < 0.05; α <0.05), the medical cost of CR group was lower significantly (p=0.042; α <0.05), and the risk of recurrence rate was significantly lower in CR group (p=0.004; α <0.05). Conclusions: Cardiac rehabilitation is known to increase functional capacity, increase left ventricular ejection fraction (LVEF), reduce medical costs, and reduce the recurrence rate of patients with CHD.


INTRODUCTION
Cardiovascular disease (CVD) is a common cause of health care problems and socio-economic globally. The impact of CHD is morbidity, disability by 10%, and mortality by 30% in the world caused by CVD. So far, Coronary Heart Disease (CHD) is the leading cause of death for CVD patients worldwide (Q. Zhang, 2019). CHD is closely related to coronary arteries that function to supply oxygenated blood for heart muscle metabolism. In CHD conditions, atherosclerotic plaque develops inside the coronary arteries resulting in arterial stenosis. Stenosis and reduced blood supply to the coronary arteries can cause dangerous effects on the heart muscle and can cause myocardial infarction (Themistocleous, Stefanakis, & Douda, 2017). Risk factors that cannot be changed in patients with CHD include age, sex, and heredity (Themistocleous et al., 2017). Risk factors that can be changed based on the results of the study show that BMI 27.1 kg/m 2 with a standard deviation of 4.2 kg/m 2 , hypertension by 67.1%, dyslipidemia by 62.1%, diabetes mellitus by 32.7%, and smoking habits by 30.3% (Viana et al., 2018). Although modifiable CHD risk factors contribute simply to the prognosis of the disease, the results of the e-ISSN: 2686-2123 p-ISSN: 2686-0538 study indicate that controlling or eliminating these risk factors can reduce substantially in the total CHD incidence (Pencina et al., 2019). Cardiac rehabilitation (CR) is considered as a foundation in secondary prevention after acute coronary syndrome and improves outcomes in CHD. CR has been shown to reduce cardiovascular mortality and hospitalization and improve the physical function of CHD patients (Francis et al., 2019). CR is a multidisciplinary intervention that improves the physical, psychological, and social functions of patients. The heart rehabilitation program includes physical exercise and strategies to reduce modifiable risk factors such as diabetes mellitus, hyperlipidemia, hypertension, smoking habits, and increase adherence to pharmacological and nonpharmacological therapies (Aguiar et al., 2017).
Decreased activity in patients with CHD can cause to decrease in physical function and physical capacity of the patient. Multidisciplinary CR does not only focus on physical activity but is associated with modification of risk factors that can aggravate the prognosis of CHD. This literature review to determine the effectiveness of CR in coronary heart patient disease.

METHOD
This present study was a literature review discussing cardiac rehabilitation for coronary heart disease patients. Google Scholar, Pubmed, Proquest were chosen as the database. This study applied a Randomized Controlled Trial, Retrospective Chart Review, Literature View, Meta-analysis.

Author
Aims Method Result Marita, Ina., Sastradimaja, Sunaryo B., Tiksnadi (2013) To evaluate the effect of a shortterm CR program on quality of life in patients with coronary artery disease.
Method: Quasi-Experimental Study used repeated measurements in consecutive sampling Sample: 11 patients with CAD without a control group Intervention: Before being given the CR program, the respondents measured their vital signs and performed a submaximal exercise test to determine their basic training capacity using a 6minute walking test (6 MWT). Respondents were given aerobic exercise modalities using a treadmill (under the supervision of a doctor) in the hospital, and walking at home 3-5 times per week (in the hospital 2 times and at home 3 times).
The duration of the exercise modality was ≥30 minutes, consisting of warmup (≥5 minutes), aerobic exercise (≥20 minutes), and cool-down (≥5 minutes). Intensity exercise in the hospital was 70-85% of the maximum HR and 60-70% of the VO2 max, while 60-75% of The results showed that the mean of physical health component before the intervention was 43.04 with a standard deviation of 5.7, while the mean of physical health component after the intervention was 87.16 with a standard deviation of 10.9. The results of the further analysis showed that there was a significant difference between the physical health component before and after the intervention (p = 0.001; α <0.05).
The mean of mental health component before the intervention was 63.93 with a standard deviation of 15.4, while the mean of mental health component after the intervention was 87.29 with a standard deviation of 8.8. The results of the further analysis showed that there was a significant difference between the mental health component before and after the intervention (p = 0.001; α <0.05).
The mean of QoL before the intervention was 49.09 with a standard deviation of 8.4, while the mean of QoL after the intervention was 87.27 with a standard deviation of 8.5. The results of the further analysis showed that there was a significant difference between the the maximum HR was for home training. The intervention was given for 4 weeks, ie every visit to the respondent's hospital was given counseling related to risk factors, stress management, and health education.
Chen, Liu, & Chen (2015) Evaluate the medical costs and recurrence rate of acute myocardial infarction after cardiac rehabilitation

Method: Retrospective Study
The total sample was 432 respondents. In this study was divided into 2 groups: 1 st group (given cardiac rehabilitation, n = 43 respondents) and 2 nd group (without cardiac rehabilitation, n = 389 respondents) The result showed that 1 st group had lower risk of acute myocardial infarction recurrence than 2 nd group (HR 0.640; 95% CI 0.197-1.863; p = 0.004). The medical cost in 1 st group was lower than in 2 nd group (HR 0.947; 95% CI 0.934, 0.981; p = 0.042). Intervention: Hospital CR The exercises were given 3 times a week (24 sessions) and were recommended for home-based exercises based on the European Society of Cardiology guidelines.

Rees
Home-Based CR 1) Respondents were given training in the cardiac rehabilitation unit once a week; 2) Respondents did the exercises at home monitored by a remote electrocardiographic monitoring device (NUUBO®); 3) Home-based exercise included walking at 70% of HR reserve (during 1 st month) and 80% of HR reserve (during 2 nd month) for 1 hour per day, carried out for 5-7 days per week.
The results showed that the mean QoL in the Hospital-based cardiac rehabilitation program group was 63.63 with a standard deviation of 21.00, while the mean in the Home-based cardiac rehabilitation program group was 43.62 with a standard deviation of 24.20.
The analysis showed that there was a significant difference between the Hospitalbased cardiac rehabilitation program and the Home-based cardiac rehabilitation program group (p = 0.004; α <0.01). The results showed that after being given CR program intervention, most of the self-efficacy increased, namely 50.00%, self-regulation by 58.80%, self-care 46.20%, and QoL by 72.50%. However, most of the BMI did not experience a change of 70.00%.

Intarakamhang
The analysis showed that there were care, quality of life, and body mass index.
training; 2) Counseling for patients and caregivers regarding simple diet control (low sugar, low salt, low fat, stress reduction) is recorded in a diet logbook; 3) health advice was given one week after the patient is discharged from the hospital; 4) Individual or group counseling at a cardiac rehabilitation clinic for 30-60 minutes, carried out 2 weeks after the patients were discharged from the hospital; 5) Evaluation was carried out based on the logbook related to exercise and diet and a post-test was carried out after 6 weeks of discharge from the hospital. significant differences in self-efficacy (p = 0.005; α <0.05), self-regulation (p = 0.000; α <0.05), BMI (p = 0.001; α <0.05), and QoL (p = 0.000; α <0.05) before and after being given the CR program in patients with CAD.
Resistance training was given 3 sessions of 150 minutes per week. Endurance training consisted of cycling (2x7 minutes), walking or treadmill (2x7 minutes), arm or rowing ergometry (7 minutes), and dynamic exercise (2x7 minutes).
The results showed that there were significant differences between the home-based group, the center-based group, and the control group (group x time interaction, p =0.04; α <0.05) with a greater increase in the home-based group (p =0,03; α <0.05) and the center-based group (p =0.04; α <0.05) were compared with the control group.

Vieira, Melo, Machado, & Gabriel (2018)
To determine the effectiveness of the home-based phase III CR specific exercise program for 6 months carried out conventionally (booklet) or virtual reality (Kinect) on quality of life and depression, anxiety and stress, and executive function.

Method: Randomized Controlled Trial
Sample: 33 patients with coronary artery disease (CAD) were divided into 3 groups, namely 1 st intervention group (IG1, n=11 respondents with homebased CR using a computer and Kinect), 2 nd intervention group (IG2, n=11 respondents with home-based CR using a paper booklet), 3 rd control group (CG, n=11 respondents with usual care) Intervention: 1 st level was 65% of the heart rate reserve, 2 nd level (3 months passed) was 70% heart rate reserve. Exercises were given 3 times a week for 6 months, in addition to the training The study results showed that there were a significant increase in conflict resolution and selective attention in the IG1 group (homebased CR used computer and Kinect) compared with the control group at the initial moment to the final moment measurement (p = 0.021; α <0.05) and compared to IG2 (Home-based CR used a paper booklet) on the measurement of the middle moment with the final moment (p=0.001; α <0.05), the initial moment with the final moment (p=0.002; α <0.05). Intervention: Rehabilitation Group: 1) Phase II began in the second week after the patient was discharged, which had 2 courses (each course 3-4 weeks); 2) The form of exercise was walking and aerobic; 3) Workload assignment: HR lower than 130 bpm (or resting HR plus 30 bpm), Borg Scale for exercise intensity measurement; 4) Respondents did physical exercise 2-3 times a week (interval or continuous) for 15-30 minutes; 5) Phase III started from the third month to 6 months; 6) The target HR was 60-75% of the maximal HR; 7) Th RPE score was no >12-16; 8) Exercise intensity was 300-400 kcal/time; 8) The intensity was 30-45 min/time, not <3-5 times a week. Control Group: Usual care + conventional drug therapy after percutaneous coronary intervention The study results showed that there was a significant difference between the cardiac rehabilitation group and the control group regarding the recurrence of angina pectoris (p = 0.002; α <0.05), rehospitalization (p <0.001; α <0.05).
The mean distance for 6MWT phase II CR in the cardiac rehabilitation group was 324.09 meters with a standard deviation of 63.79 meters, while the mean in the control group was 257.86 meters with a standard deviation of 68.17 meters. The analysis showed that there was a significant difference in the 6MWT distance in the rehabilitation group and the control group (p = 0.001; α <0.05).
The mean distance for 6MWT phase III CR in the cardiac rehabilitation group was 412.71 meters with a standard deviation of 74.37 meters, while the mean in the control group was 302.27 meters with a standard deviation of 101.81 meters. The analysis showed that there was a significant difference in the 6MWT distance in the rehabilitation group and the control group (p = 0.001; α <0.05). The results showed that there was a significant increase in exercise capacity ide +1 metabolic equivalent exercise ECG stress test and the 6min walk test +75.4 minutes regardless of age, gender, body mass index, and nicotine dependence (p <0.05).

Zhang & Chang (2019)
Analyze the results of a combination of PCI and physical exercise with PCI without physical training.
Method: Systematic Review through Embase, PubMed, Wanfang Data, Cochrane databases with 502 studies taken.

Q. Zhang (2019)
To Intervention: The study was divided into 2 groups, namely 1 st group with a higher exercise dose (3 times a week for 12 weeks or as many as 36 sessions), while 2 nd group was given exercise twice a week for 8 weeks or 16 sessions with the same intensity and standard exercise protocol for 1 hour.

Prabhu, Maiya, & Prabhu (2020)
Reviewed the effects of CR related to the level of physical activity, functional capacity, and quality of life of patients undergoing coronary revascularization.
Method: Structured literature search in ProQuest, PubMed, Scopus, and CINAHL with a total of 2,020 studies taken.
There were 21 articles reviewed and the majority of studies report that physical activity and exercise programs based on home-based and center-based via rehabilitation include treadmills and cycle ergometry in phase 2 cardiac rehabilitation showing a significant increase in physical activity and functional capacity levels after the procedure coronary revascularization.

Functional Capacity
The results of the study by Da Silva et al., (2019) shows that ISWT distance before and after intervention in comprehensive CR group (p <0.001; α <0.05) and CR-only group (p <0.001; α <0.05) with functional capacity is greater with comprehensive CR compared to controls. Exercise or performance capacity is calculated by the metabolic equivalent of task (MET), which is equivalent to the activity. METs are consumed 3.5 mL of oxygen/kg body weight/min. MET maximum strength represents maximal oxygen consumption or max VO2. Physical exercise in CR increases stroke volume (SV) and increases oxygen consumption in the network (environmental agent). Physical training can improve blood flow to organs and improve the mitochondrial function of the skeletal muscle system and endothelial cell function. Besides physical exercise can also delay the accumulation of lactic acid in muscles and increase lung ventilation (Haybar, Habib., Shirani, Teimoor., Pakseresht, 2017).

Left Ventricular Ejection Fraction (LVEF)
The results of the study by H. Zhang & Chang, (2019) show that the left ventricular ejection fraction (LVEF) increases significantly in the intervention group (p <0.05, 95% CI 1.50, 4.14).
In CR patients are programmed to control blood pressure, reduce lipid levels, education for smoking cessation, diabetes control, reduce obesity, and lifestyle modification. Although physical exercise can affect the synthesis of free radicals, physical exercise also increases work capacity without simultaneously increasing the production of free radicals. This fact shows that physical exercise can be done with less oxidative stress and can reduce insulin resistance after myocardial infarction with hyperinsulinemia (Sadeghi et al., 2013).
The process of fibrinolysis and myocardial perfusion is improved after physical exercise and can improve systolic function and ventricular fraction ejection by increasing heart muscle. This is caused by the sympathetic influence that occurs during exercise so that the pulse rate increases (Sadeghi et al., 2013).

Medical Cost
The results of the study by Chen et al., (2015) show that the medical cost in CR group is lower than the non-CR group (HR 0.947; 95% CI 0.934, 0.981; p = 0.042). Myocardial infarction patients are managed on the clinical pathway (including CR administration) have a lower average length of stay (LOS) than patients who are not managed on a clinical pathway basis. This can affect the number of medical cost patients, meaning that patients undergoing cardiac rehabilitation are lower medical costs (Chen et al., 2015).

Recurrence
The study by (Chen et al., 2015) shows that the heart rehabilitation group is a lower risk of recurrence of acute myocardial infarction than the non-CR group (HR 0.640; 95% CI 0.197-1.863; p = 0.004). Patients undergoing cardiac rehabilitation are known to reduce the risk of reinfarction, functional status increases, and risk factors such as smoking or hypertension can be controlled. Besides, the CR program also involves multidiscipline conducted by a team of experts such as further education and counseling for patients after acute myocardial infarction thereby reducing the risk of recurrence (Dunlay, Shannon M., 2014).