Cardiac Rehabilitation: What Makes it Effective?

Cardiovascular disease (CVD) is the leading cause of morbidity, mortality and disability globally imposing a significant burden on individuals, families, and healthcare systems1. Each year in Ireland, over 4000 deaths are attributed to ischaemic heart disease.

The growing population of those living with chronic CVD, heart failure and valvular heart disease are at a higher risk of secondary events, therefore it is essential that these patients receive effective, evidence-based secondary prevention, leading to optimization of cardiovascular health, improved functional capacity and enhanced quality of life.

For over 50 years cardiac rehabilitation (CR) is established as the proven cornerstone of optimal CVD management by reducing the risk of cardiovascular mortality and hospital readmissions, delivering improvements in patient outcomes and providing cost-effective care in these populations. 2,3,4,5

CR is a medically supervised, systematic, multidisciplinary programme offering internationally agreed core components across the continuum of care from the acute inpatient to longer term outpatient phase. 6

The key components which underpin the effectiveness of CR include supervised, guideline-directed exercise training, patient education, behaviour modification, psychosocial management and comprehensive risk factor management. 6,7

Fully comprehensive CR, recommended by clinical practice guidelines internationally, requires these core components to achieve reductions in mortality and morbidity.8

Timely access is also critical and prompt CR enrolment is associated with both improved participation and outcomes. For example, CR participation is reduced by 1% for every one-day delay in enrolment9, whereas early enrolment is linked with a 67% greater improvement in exercise capacity among patients enrolled in a programme within 15 days after hospital discharge compared to patients enrolled 30 or more days following discharge. 10,11

Individualized CR Programme:

A comprehensive evaluation and assessment of clinical status, CVD history, guideline-directed medication therapy, cardiovascular risk factors, dietary habits, body composition, exercise habits and capacity, psychological health and quality of life form the basis of an individually tailored CR programme. Although the risk of an adverse event is low 12 there is agreement across CR guidelines that all patients entering CR should be stratified according to risk for the occurrence of adverse events during exercise and for risk of progression of atherosclerotic disease. 6,7,13

Exercise Training:

Exercise training is central to CR due to the robust evidence base demonstrating its role in reducing mortality and morbidity.14,15,16,17,18,19,20,21 Cardiorespiratory endurance training is recommended as the foundation of most exercise prescriptions for adults with CVD as it represents the most effective way to increase cardiorespiratory fitness which reduces mortality risk. 22 The aim of the exercise prescription is to achieve a safe but therapeutic level of exercise training and progression of exercise intensity. Establishing safe and effective exercise programming is rooted in physiological responses to exercise not solely on subjective indicators.

International consensus recommends an initial exercise prescription based on a functional capacity test which is symptom-limited to assess exercise capacity, heart rate, blood pressure, occurrence of arrhythmias, and ECG response. Cardiopulmonary exercise testing is recognised as the gold–standard using either a bicycle ergometer or a graded treadmill exercise test, and conducted on regular medications.23,24,6

Exercise prescription is based on FITT -VP principles: Frequency, Intensity, duration (Time), Type Volume and Progression.25

CR clinical guidelines widely recommend 2-4 supervised exercise sessions per week complemented by unsupervised home sessions. 6,23,24,26,27 Intensity may vary between 40-80% of heart rate reserve (HRR) depending on the patient’s profile and their stage of progression through the programme.

Perceived exertion should be in the moderate to moderate – to – high intensity range with higher-intensity interventions have been demonstrated to be safe and lead to superior outcomes. 28 Most CR guidelines specify up to 60mins per exercise session incorporating warm-up, cool down and resistance training. 6

Functional capacity (measured in Metabolic Equivalents – METs) achieved at CR completion is a stronger predictor of all-cause mortality than METs achieved at CR entry. 29 Progression of each patient’s exercise prescription is required to achieve the necessary cardiovascular adaptations leading to mortality benefit.22

Direct staff supervision should occur during exercise training until a safe exercise response has been demonstrated, with a variety of modalities employed to monitor patients including continuous ECG monitoring. After an initial period this monitoring may decrease appropriately if there is no evidence of abnormal ECG or haemodynamic findings, abnormal signs and symptoms or intolerance of exercise. 6, 7

Comprehensive CVD Risk Factor Management:

CR programmes incorporate secondary CVD prevention and comprehensive risk factor management based on the clinical assessment at programme onset. Evidence based interventions are implemented to optimise risk factor control in alignment with patient-centred goals. In line with the principle of Making Every Contact Count 30, risk factor management encompasses the following aspects:

• Lifestyle modifications
• Smoking Cessation
• Nutritional Counselling
• Weight management
• Hypertension Management
• Lipid Management
• Diabetes Management
• Psychosocial Care
• Medication Management: (i.e. reconciliation of prescription, treatment optimisation and / adherence)
• Clinical Management: Patients with cardiac conditions have a broad spectrum of risk of developing arrhythmias that is not easily discernible, and CR represents an ideal opportunity to recognise and manage silent ischaemia 31 and arrhythmia
• Continuity of Care: bridging cardiovascular care ensuring continuity of appropriate secondary prevention management.

Psychosocial Management: The psychological impact of heart disease is considerable, and psychological distress is highly prevalent in patients with CVD. Anxiety, depression and insomnia disorder affect approximately one-third of people with CVD, and up to one in four cardiac patients experience clinically significant levels of post-traumatic stress (PTSD)32,33,34,35. As a minimum, CR patients should be screened for clinically significant psychological distress as this is linked to increased future cardiac events and mortality, poorer quality of life, increased suicide risk, greater healthcare costs and poorer long-term psychological adjustment 32 However, many cardiac patients (e.g. survivors of sudden cardiac arrest, SCAD) also present with unique and complex psychological needs that are best delivered by an experienced clinician (e.g. device-related shock anxiety, PTSD) 36,37 Systematic reviews demonstrate that the psychological component drives the benefits achieved by CR, and that psychological interventions not only improve psychological distress and quality of life, but also reduce cardiac events and hospitalizations 4, 38,39,40 When fully integrated with CR, these interventions are also highly cost-effective (e.g. group sessions) and deliver an incremental benefit on hard endpoints 41A cardiac psychologist working as an integral

part of the MDT will also provide expertise in weight management, psychosexual counselling, insomnia treatment, medication adherence, family support (e.g. caregiver burden in heart failure), maintaining lifestyle changes (e.g. exercise, smoking cessation) and enhanced communication with the cardiology team.

Patient Education and self-management:

CR Adherence and Exercise ‘Dose’:

The number of CR exercise sessions attended is inversely related to major cardiovascular adverse events (MACE). This benefit appears to be linear, with greater risk reduction associated with higher doses, and no upper threshold. For example, , the risk of MACE is significantly lower both for patients completing a median of ≥12 sessions versus less, and those attending CR on average >2 sessions per week. Similarly, a continuous increase in attendance of 1 session is significantly associated with a 1-2% reduction in MACE risk with no ceiling to benefit. 44

In conclusion, for CR to be effective a multi-component and multi-disciplinary programme of care is required. While exercise training remains a central aspect of CR with strong evidence supporting its benefit, other components such as education and particularly psychosocial management are essential.8

The ongoing challenge is the implantation of this high-quality model in different settings, ensuring all eligible patients can access CR in a timely way.

References available on request

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