Work capacity and left ventricular function during rehabilitation after myocardial revascularization surgery.

Abstract

A prospective randomized trial was conducted to evaluate the effects of exercise-based cardiac rehabilitation after myocardial revascularization surgery (MRS) on work capacity (measured in mets) and left ventricular function as determined from ejection fraction (LVEF). Twenty-eight patients undergoing MRS were randomly assigned to experimental (aerobic exercise, n = 19) or control (muscle relaxation and low-level exercise, n = 9) groups. Patients were studied before surgery (T1) and 2 (T2), 8 (T3), and 24 (T4) weeks after surgery with first-pass radionuclide angiography both while they were at rest and during maximal upright cycle ergometric exercise. Subsets of patients were also studied at T2, T3, and T4 at a standard workload of 75 W, and during maximal exercise 1 year after surgery (T5). Work capacity improved in both groups although significantly more so in the experimental group (3.9, 3.8, 6.0, and 7.3 mets and 3.7, 3.7, 4.9, and 5.7 mets at TI, T2, T3, and T4 in the experimental and control groups, respectively). The differences between groups were significant by T3. Peak exercise LVEF increased significantly in both groups from T1 to T2 then decreased at T3 and remained unchanged through T5. Peak exercise LVEF at T3 to T5 remained significantly above that observed at T 1. LVEF responses were not related to the exercise program. During a standard workload, heart rate decreased, blood pressure increased, and LVEF did not change in either group. After conclusion of the formal protocol (T4), work capacity and LVEF did not change for either group throughout an additional 6 months (T5). We conclude that exercise training significantly enhances both the magnitude and rate of the increase in work capacity after MRS, but that peak exercise LVEF is not influenced by the exercise program. Circulation 69, No. 4, 748-755, 1984. THE GROWTH of rehabilitation programs for patients with cardiovascular disease has been impressive during the 25 years since Hellerstein and Ford first presented "an orderly plan for the rehabilitation of the patient with heart disease. "' Exercise-based rehabilitation programs have a demonstrated beneficial effect on clinical status, as evidenced by improved work capacity,2' 3reduction in incidence of attacks of angina pectoris,4 and indications of a reduction in rates of morbidity/mortality.5 6 Their effect on left ventricular function, which is an important prognosticator of sur-

Workload Accomplished in Phase III Cardiac Rehabilitation

“…Despite the unequivocal evidence of exercise-based rehabilitation programs in both rehabilitation and secondary prevention in patients with cardiovascular disease [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ], physicians are still referring patients to programs in inadequate numbers. Potentially, this non-referral bias may be due to a poor understanding of how well exercise guidelines are implemented.…”

“…Cardiac rehabilitation is of established benefit for decreasing the risk of future cardiovascular events [ 1 , 2 , 3 ], delaying/reversing the progression of atherosclerotic disease [ 4 , 5 , 6 ], reducing the rate of reinfarction and death [ 7 , 8 , 9 ], and accelerating the rate of recovery of functional capacity after clinical episodes [ 10 , 11 ]. The value of cardiac rehabilitation is evident even after accounting for contemporary revascularization and pharmacologic therapy [ 12 ].…”

Cardiac Response to Exercise in Health and Disease

“…The reason for the larger per cent increase in for patients may be a result of several factors: a reluctance of investigators to have similar endpoints for patients during their initial exercise test compared with subsequent ones; allowing patients to hold on to handrails while being tested on a treadmill; and if the initial test is administered within the first 12 weeks of recovery from a cardiac event or surgery, increases are partially (approximately 10%) a result of the healing process. 172 For example, Vanhees and col leagues 171 and Ehsani and coworkers 146,165 showed dramatic increases in measured after 3 and 12 months of endurance training, but maxi mum heart rate also increased 5 to 15 beats/min from initial to final testing. Also many patients were low fit initially ( less than 30 to 25 ml • kg -1 • min -1 ); thus, they appear to have a greater potential for improvement.…”

Functional Translation of Exercise Responses from Exercise Testing to Exercise Training: The Test of a Model

“…It is beneficial on a dose-response basis, up to amounts of training of several times professional society guidelines [1,2] and only associated with health problems at levels consistent with heavy athletic training in middle-aged and older individuals [1,2,5]. In patients with chronic diseases, exercise forms a cornerstone of the treatment scheme of rehabilitation programs being of value both in terms of accelerating the rate of recovery [6], secondary prevention [7][8][9], and is even of value after contemporary medical care (percutaneous interventions and statins) is accounted for [10]. However, exercise training can present a significant risk of clinical events [11], particularly in the setting of unaccustomed heavy exercise in sedentary individuals [12] or in the setting of myocardial ischemia during exercise training [13].…”