PATIENT SELECTION AND RISK STRATIFICATION
PATIENT SELECTION
Cardiac rehabilitation encompasses short-term and long-term goals that are to be achieved through exercise, education, and counseling.
Patients generally fall into following categories:
Lower-risk patients following an acute cardiac event
Patients who have undergone coronary bypass surgery
Patients with chronic, stable angina pectoris
Patients who have undergone heart transplantation
Patients who have had percutaneous coronary angioplasty
Patients who have not had prior events but who are at risk because of a remarkably unfavorable risk factor profile
Patients with stable heart failure
Patients who have undergone noncoronary cardiac surgery
Patients with previously stable heart disease who have become seriously deconditioned by intercurrent, comorbid illnesses
The short-term goals of cardiac rehabilitation include the restoration of the physical, psychological, and social condition, while the long-term goals involve the promotion of heart-healthy behaviors that enable the individual to return to productive and/or joyful vocational and avocational activities.
The cardiac rehabilitation programs benefit women and men equally. Elderly patients also can derive significant benefit from rehabilitation programs.
RISK STRATIFICATION
The risk stratification process is very valuable for cardiac patients; it serves as the basis for individualizing the prescription of exercise training and for assessing the need and extent of supervision required.
The risk stratification process is based on the assessment of the patient's functional capacity, on the patient's educational and psychosocial status, on whether alternatives to traditional cardiac rehabilitation can be used, and on whether the patient is suffering from myocardial ischemia, ventricular dysfunction, or arrhythmias.
FUNCTIONAL CAPACITY
The term functional capacity refers to the maximum ability of the heart and lungs to deliver oxygen and the ability of the muscles to extract it. Functional capacity is measured by determining the maximal oxygen uptake (VO2 max) during incremental exercise.
In most patients, a rough calculation of functional capacity can be performed by using multiples of 1 MET (metabolic equivalent, 3.5 mL O2 uptake/kg/min). In complicated patients, such as those with severe left ventricular (LV) dysfunction and congestive heart failure (CHF), the functional capacity can be ascertained with greater accuracy by using cardiopulmonary exercise (CPX) testing. Most cardiac rehabilitation facilities, however, are not currently equipped for CPX.
The following factors influence functional capacity:
Ø Age
Ø Precardiac event physical capacity
Ø Treatments and bed rest during the event
Ø Fluid volume, such as relative dehydration or volume overload in patients with CHF
Ø LV dysfunction
Ø Residual myocardial ischemia
Ø Skeletal muscle performance, such as deconditioning or in the presence of concurrent, non-cardiac illness
Ø Autonomic function, such as diabetic neuropathy
Ø Peripheral vascular status
Ø Pulmonary status
Ø Other systemic illnesses, especially orthopedic problems limiting flexibility and locomotion
Every attempt should be made to recognize the potential effects of these factors on functional capacity in order to minimize risk of the individualized reconditioning program that is being formulated.
MYOCARDIAL ISCHEMIA
Symptomatic or asymptomatic (silent) myocardial ischemia may limit the patient's exertional capacity by causing limiting angina, dyspnea, or fatigue.
VENTRICULAR DYSFUNCTION
Fixed LV dysfunction or damage may be present in the absence of angina. Patients with LV dysfunction develop early dyspnea and easily become fatigued.
Cardiopulmonary exercise testing preferably should be performed to determine the functional capacity in an objective manner.
Exercise intolerance in patients with LV dysfunction is due to skeletal muscle hypoperfusion resulting from inadequate cardiac output that can be better quantified by measuring VO2 max.
ARRHYTHMIAS
Ventricular irritability and complex ventricular arrhythmias require assessment through the use of signal-averaged electrocardiogram (ECG) or electrophysiologic studies.
Appropriate medical or device treatments should be undertaken whenever feasible prior to beginning phase 2 of the cardiac rehabilitation program.
Very close surveillance is necessary in patients with significant cardiac arrhythmias during their exercise training routines. Concomitant rhythm monitoring with telemetry, Holter or event monitoring should be considered. In many cases of serious arrhythmias, therapy remains controversial and the safety of is exercise unclear; such uncertainties complicate the decision-making process.
Patients with severe ventricular arrhythmias and uncontrolled supraventricular arrhythmias should be excluded from exercise training unless proper evaluation and effective therapy has been instituted. Patients with devices, such as pacemakers and defibrillators, should be carefully monitored during exercise.
Rate-responsive pacemakers are quite helpful even for those patients who are completely pacemaker-dependent. In case of implantable cardioverter defibrillators (ICDs), exercise training can be provided as long as underlying arrhythmias are controlled with pharmacotherapy.
Heart rate should be kept well below the threshold at which the anti-tachycardia algorithm of the ICD begins.
EDUCATIONAL AND PSYCHOSOCIAL STATUS
Approximately 20-25% of acute myocardial infarction (MI) patients demonstrates severe psychological stress or major depression; they also show higher morbidity and mortality.Clinically significant depressive symptoms are found in 40-65% of patients after an MI.
Exercise does provide some benefit, but severe cases may require specific therapy that has been shown to enhance the benefits derived from subsequent cardiac rehabilitation.
The promotion of self-efficacy and control over one's activities is of paramount importance for boosting self-confidence.
Coronary-prone behavior (CPB) is known as a cardiac risk factor, but its effect on prognosis is unclear. Some data suggest that the modification of CPB can improve the coronary disease prognosis.
Initially, continuous ECG monitoring is recommended for most patients during cardiac rehabilitation exercise training; however, clinicians may decide whether to use continuous or intermittent ECG monitoring. After the initial period, the use of electrocardiography depends on the clinical judgment of the supervising physician.