Demonstration of Training Effect During Chronic f-adrenergic Blockade in Patients with Coronary Artery Disease

Attenuation of exercise-induced increases in heart rate and cardiac output by chronic f3adrenergic blockade has been thought to conmpromise benefit of exercise training in patients with coronary artery disease (CAD). To assess this important issue, 35 CAD patients were evaluated by a 3-month walkjogcycle training program: 14 patients received no blocker (group 1), 14 received propranolol,' 30-80 mg/day (group 2), and seven patients'received propFan'olol, 120-240 mg/day (group 3). The extent of CAD, resting heart rate before training blood pressure and V02 max were similar (p = NS) in each group. The maximal exercise heart rate (mean i SD, 147 ± 21 beats/min in group 1 vs 120 ± 10 beats/min in group 2 and 115 12 beats/min in group 3 (both p < 0.05 vs group 1). The V02 max before training was 25 5.0 mI/kg/mm in group 1 vs 23 3.2 ml/kg/min in group 2 and 26 ± 2.8 ml/kg/min in group 3 (allp = NS). Training consisted of three 1-hour periods per week at a heart rate of 70-85% of the maximal pretraining heart rate. In each group, VO2 increased (p < 0.05) after training: group 1, 27%; group 2, 30%; group 3, 46%. The'double product was unchanged after training (p = NS) in each group. These data indicate that substantial training effects may be achiev'ed in CAD patients despite therapeutic doses of fl blockers and a reduced training HR. Thus, there appears to be no indication to reduce blockers in CAD patients engaged in cardiac rehabilitation.