Case Report Secondary Prevention Program through Hybrid Tele-Cardiac Rehabilitation Using a Combination of Vigorous-intensity Interval Training and Low-Intensity Home-based Exercise in Patient with Refractory Angina Post-Percutaneous Coronary Intervention

Refractory angina (RA) refers to symptoms lasting >3 months due to reversible ischemia occurring with coronary artery disease, which cannot be controlled by increased medical therapy or revascularization, including percutaneous coronary intervention (PCI). It may result in a significant impact on patient outcomes such as exercise limitation, biopsychosocial disorders, and decreased quality of life. Participation of patients with RA in cardiac rehabilitation (CR) reduces angina frequency and increases exercise capacity. A 64-year-old male has undergone PCI and experienced RA. This patient was given a CR program to increase his functional capacity as a secondary prevention of cardiovascular disease through a center-based combined with a home-based CR program. Aerobic exercise was provided as hospital-based, vigorous-intensity interval training and low-intensity, home-based exercise. Problems found were RA that often appeared during activity and low cardiorespiratory endurance and muscular fitness. Psychological issues due to fear of recurrent heart attacks resulted in physical activity limitations. Angina symptoms and hand grip strength improved after 2 weeks, although the muscular fitness classification was still poor. During the program, he could achieve the exercise heart rate target without any symptoms. After 4 weeks, there were still frequent VES with couplet episodes, so the patient was still classified as high-risk stratification. Though the risk stratification was still high, the patient was allowed to enter phase III CR with the prescription of moderate-intensity aerobic, low-intensity resistance, flexibility, and breathing exercises. These exercises were given based on recommendations for the average adult to maintain his level of physical activity and promote lifelong healthy behavior. Hybrid tele-cardiac rehabilitation through vigorous-intensity interval training and low-intensity home-based exercise combination in a post-PCI RA patient improved functional capacity as a key component for cardiac prevention.


Introduction
Refractory angina (RA) is one of the symptoms experienced by patients with coronary artery disease (CAD), which shows angina symptoms that last more than 3 months and cannot be controlled by increasing the dose of medication and revascularization. 1 This complaint can affect the patient's clinical and functional outcomes, which can cause limitations in the ability to carry out activities of daily living (ADL) or exercises, leading to decreased quality of life. 2 The annual mortality rate of patients with RA ranges from 3 to 21%.A study found that long-term mortality in patients with RA is low, below 4% per year, thought to be due to improvements in secondary prevention strategies, evidence-based medical therapy, and revascularization techniques.Secondary prevention strategies through dietary changes, exercise, and smoking cessation may contribute to decreased mortality. 3cardiac rehabilitation program (CR) is a non-pharmacological treatment that is proven to reduce the frequency and symptoms of angina obtained as a result of exercise. 4,5However, the emergence of RA symptoms during activity can cause patients to limit activities that can affect the physiological effects of exercise. 6A CR program is needed to increase the patient's tolerance for carrying out activities. 7The main goal is to return patients to their normal activities and increase their functional capacity. 5,8Increased functional capacity is associated with reduced long-term complications of cardiovascular diseases. 9though the benefits of CR are widely known, sometimes patients cannot attend this program.The identified barriers are psychosocial factors, travel distance and accessibility to CR facilities, and cost of the CR program; therefore, home-based CR was developed to overcome these barriers. (10,11) The present case report aimed to identify whether the CR program through hybrid tele-cardiac rehabilitation could improve the functional capacity needed for daily activities and as a secondary prevention program.

Case Illustration
A male patient, 64 years old, was undergoing phase II CR after a percutaneous coronary intervention (PCI) procedure that was done 10 weeks ago.At the beginning of phase II CR, the patient had difficulty undergoing the CR program due to transportation, cost, and access to the hospital factors.This patient was then given a combination of center-based and homebased CR programs, with a detailed program described in Table 1.This definition is consistent with the patient.Although he had undergone PCI seven times, the complaint of angina during the activity was sometimes still felt, so the patient limited his activities.
Angina symptoms in patients with RA significantly limit their physical activity due to persistent debilitating chest discomfort.Persistent chest discomfort is often commonly believed to be a lifethreatening cardiac event.This results in psychological problems in the form of increased anxiety, depression, and other negative behaviors and further impairs both the physical and psychosocial domains of quality of life. 1,14Patients with RA also have pronounced cardiac and concomitant disease and a high fatality rate.The mortality rate after one year was higher in patients with RA compared to patients who underwent revascularization.In patients with stable angina pectoris with pharmacological treatment, the one-year mortality is approximately 2-4%. 14 this patient, the revascularization procedure further limits his activities.It is already known that revascularization will decrease the functional capacity, causing patients to fall into a sedentary lifestyle. (15) can significantly impact patient outcomes, causing exercise limitations. 13,16 is widely known that the presence of  The underlying cause or appropriate therapeutic measures are important in the management.Anginal symptoms with or without documented ischemia are associated with increased adverse cardiovascular events. (13)Revascularization with PCI and CABG is given in moderate to severe cases. (1)Non-revascularization interventions for RA provided as a symptomatic approach, such as spinal cord stimulation, transcutaneous electrical nerve stimulation, epidural anesthesia, enhanced external counterpulsation, and laser revascularization were given. 1,14Cognitive behavioral therapy is an approach given to improve patients' ability to manage their symptoms. 1 is one of the treatments advocated in managing patients with RA. 21,22 CR is also known as a secondary prevention program.The main goal is to help the patients return to their normal ADLs by increasing their functional capacity.
Functional capacity is associated with a person's ability to perform everyday living tasks.It may also refer to aerobic fitness, or the body's ability to use oxygen efficiently under a workload.The primary metric of functional capacity is cardiorespiratory fitness (CRF), usually assessed as maximum oxygen uptake (VO2 max), which is ideally measured by cardiopulmonary exercise testing.Metabolic equivalents (METs) are obtained by dividing VO2 max by 3.5. (17,23) Increasing age causes the functional capacity to further decrease due to the constantly developing process of atherosclerosis and endothelial dysfunction. (17)Functional capacity plays a role in the secondary prevention of cardiovascular disease because higher functional capacity can inhibit the process of atherosclerosis and decrease cardiovascular function. (17)Better functional capacity will also cause the patient to perform activities better so that the circle of inactivity can be broken. (17)rticipation of patients with RA in CR reduces angina frequency and increases exercise capacity as a result of exercise, weight loss, and smoking cessation.Exercise can also improve endothelial function, reduce oxidative stress and arterial stiffness, and improve myocardial perfusion. (25)This patient was given aerobic exercise to increase functional capacity from 9.56 METs to a higher rate to achieve an excellent level of functional capacity according to his age (95 th percentile). (26) adverse events during exercise. (30)The prescription of exercise in this patient was High-risk stratification is contraindicated to unsupervised home exercise programs. (10,26) refore, telemonitoring CR was provided.
The literature stated that home-based CR programs are as effective as center-based CR in CAD patients. (10,31) symptoms of the disease, such as shortness of breath, fatigue, pain, or angina, causes fear of recurrence of symptoms during activity so that the patient falls into a state of physical inactivity.The physical inactivity model shown in Figure 1 schematically explains the relationship between angina and physical inactivity in CAD patients.
adopted from the Corre et al. protocol with some modifications, such as the device used (a treadmill) and exercise intensity (vigorous).The reason for the modification was our consideration of RA that could occur during exercise.This patient was also given a homebased CR program monitored via WhatsApp calls to achieve adequate training volume.
ensure the safety of the homebased CR program, education was also given about the symptoms and signs of exercise intolerance, symptoms and signs of adverse events, and what must be done to overcome it.Symptoms and signs of exercise intolerance include angina, unusual or severe shortness of breath, abnormal diaphoresis, pallor, cyanosis, cold, and clammy skin, central nervous system symptoms such as vertigo, ataxia, gait problems, or confusion, leg cramps or intermittent claudication, and physical or verbal manifestations of severe fatigue or shortness of breath. (32)At the end of hospital-based CR, the patient achieved a good fitness classification, but he still experienced arrhythmias, so the risk stratification was at high risk.Even though the high-risk stratification prohibited us from giving a home-based exercise program, a good level of functional capacity, low-and moderateintensity exercise prescription, and a good performance of exercise without adverse events during hospital-based CR allowed us to try to give home-based exercises.With a recommended prescription for an average adult, we hope the patient continues to increase his physical activity and exercise regularly.Conclusion Hybrid tele-cardiac rehabilitation through vigorous-intensity interval training and low-intensity home-based exercise combination in a patient with RA post-PCI improved functional capacity as a key component for a secondary prevention program.In the presence of barriers to center-based CR, hybrid tele-cardiac rehabilitation may become an option.Although the studies on the role of telecardiac rehabilitation are still limited, the implementation of this program for RA patients is considered effective and safe.

Table 1 . Exercise Prescription
activity persists.He experienced several times heart attacks and underwent PCI six times.However, he refused to undergo coronary artery bypass graft (CABG) surgery suggested by the cardiologist due to fear of CABG complications or even death.He consumed medicines regularly but did not obey the diet and physical activity prescribed by the doctor.There was no specific psychological intervention given during phase II CR except for education and counseling every 2 weeks of hospital visits.This intervention focused on an explanation of the impact of the disease on his functional capability and adherence to lifelong healthy behavior.The goal of CR in the short term (4 weeks) was

Table 2 .
The Patient's Functional Assessments