Barbara J. Fletcher

Exercise testing and training in physically disabled men with clinical evidence of coronary artery disease

Abstract A prospective, randomized, controlled clinical trial in patients with coronary artery disease (CAD) and a concurrent physical disability evaluated the effects of a home exercise training program on cardiovascular function and blood lipids. Eighty-eight men between the ages of 42 and 72 years (mean 62) with documented CAD and a physical disability with functional use of ≥2 etremities including 1 arm were randomized to either a 6-month home exercise training program using wheelchair ergometry or to a control group that received usual and customary care. Both groups received dietary instructions and were requested to follow a fat-controlled diet. Exercise test variables with echocardiography and blood lipids were measured at baseline and at 6 months. The home exercise training group significantly improved both peak exercise left ventricular ejection fraction (p = 0.007) and fractional shortening (p = 0.01) between baseline to 6 months, whereas the control group showed no significant changes. Exercise training effects of decreased resting heart rate (p = 0.03) and decreased peak rate pressure product (p = 0.03) were also found in the treatment group. No exercise-related cardiac complications occurred. Both groups significantly (p ≤ 0.01) increased high-density lipoprotein cholesterol levels. These results indicate that physically disabled men with CAD can safely participate in a home exercise training program which may result in intrinsic cardiac benefits. The metabolic cost of activities of daily living imposed on this disabled popu lation may also have a positive effect on high-density lipoprotein cholesterol levels.

Efficacy of high-intensity exercise training on left ventricular ejection fraction in men with coronary artery disease (The Training Level Comparison Study)

The purpose of this study was to compare high- versus low-intensity exercise training on the change in echocardiographic left ventricular ejection fraction (LVEF) from rest to peak exercise. Sedentary men with coronary artery disease, aged 30 to 70 years, were randomized to dynamic exercise training of either low intensity, 50% of maximal oxygen consumption, n = 89; or high intensity, 85% of maximal oxygen consumption, n = 111. No other interventions were imposed and patients were evaluated at 6 months and 1 year. Both exercise groups significantly increased exercise capacity without adverse events, but the increase was greater (p = 0.02) in the high-intensity exercise group. The mean exercise test rest-peak LVEF in the high-intensity group rose from 6.20% at baseline to 6.54% in 6 months and to 6.73% at 12 months, while the low-intensity group showed no improvement at 6 months and a decrease at 12 months. Multivariate analyses revealed that treatment group (high versus low intensity) significantly contributed to the change in rest-peak LVEF. When the exercise groups were subdivided by initial baseline LVEF < or = 50% versus > 50%, those with the higher LVEF in the high-intensity group showed a greater (p = 0.05) increase in the rest-peak LVEF from baseline to 1 year. Over a 1-year period, exercise capacity improved in both exercise-intensity groups, but more so in the high-intensity group, with no adverse events. The high-intensity group, compared with the low-intensity, showed more improvement in the rest-peak LVEF, especially in those with a higher LVEF at baseline.

Phase II intensive monitored cardiac rehabilitation for coronary artery disease and coronary risk factors—A six-session protocol

To evaluate phase II intensive monitored cardiac rehabilitation using a 6-level, 6-session protocol, 31 patients were placed in a progressive 6-level exercise protocol with careful supervision and assessment of heart rate, rhythm, blood pressure and perceived exertion. Duration after the cardiac event ranged from 12 days to 8 years (median 10 months). Each exercise prescription was based on exercise testing with oxygen consumption determinations. Exercise activities were individually prescribed according to percentages of maximal MET level achieved on the exercise test. Each exercise session incorporated calisthenics, treadmill exercise, and bicycle and arm ergometry with progressively greater workloads on the various stations. All patients completed the 6 levels within 6 sessions of approximately 1 hour each, and achieved their designated 50 to 75% target heart rate with perceived exertion level 13 or less. There were no critical cardiac events, i.e., high-grade ventricular arrhythmias or myocardial infarction. All completed the 6-level protocol and progressed to a nonmonitored exercise program with no difficulty. The results of this short-term method of telemetry-monitored rehabilitation suggest benefits of proper exercise instruction, successful achievement of the 50 to 75% exercise target heart rate, detection of minor new arrhythmias and alterations of blood pressure response, adequate use of the perceived exertion scale, and a safe and effective transition to subsequent exercise programs.

Efficacy and compliance with cholestyramine bar versus powder in the treatment of hyperlipidemia

PURPOSE The purpose of the study was to compare the powder and the bar forms of cholestyramine to determine efficacy and patient compliance. SUBJECTS AND METHODS A prospective, randomized trial was conducted that included 83 healthy men and women with hyperlipidemia greater than the 90th percentile for low-density lipoprotein (LDL) or total cholesterol. Patients were randomly assigned to receive either cholestyramine powder, two packets (8 g), twice daily, or cholestyramine confectionery bar, in maple or mint flavors, two bars (8 g), twice daily. Fasting serum total cholesterol, LDL cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides were measured at baseline, after 6 to 8 weeks of following the American Heart Association Step I diet alone, and after 8 weeks of taking either the cholestyramine bar or powder. RESULTS Total cholesterol decreased significantly (p less than 0.01) by 16% in the bar group and 17% in the powder group. LDL cholesterol decreased by 28% and 29% in the bar and powder groups, respectively (p less than 0.01). There was no significant change in HDL cholesterol. Triglycerides increased in both groups, by 29% in the bar group and by 25% in the powder group. There was no difference between bar and powder in the effect on blood lipids. The majority of the lipid-lowering effect was seen within 14 days. Mean patient endpoint compliance with the therapy was 91.8 +/- 3.6% in the bar group and 94.8 +/- 2.1% in the powder group. There was no difference between groups. CONCLUSION The cholestyramine confectionery bar is as effective as cholestyramine powder in the treatment of hyperlipidemia. The majority of the lipid-lowering effect is seen within 14 days of therapy. Although patient compliance is comparable between the two forms, gastrointestinal side effects were slightly greater with the bar form. Therefore, although the bar offers an alternative form of therapy, there appears to be no advantage with regard to patient compliance or palatability.

Blood magnesium and potassium alterations with maximal treadmill exercise testing: Effects of β-adrenergic blockade

To test alterations in plasma potassium and magnesium levels with maximal exercise, 15 sedentary, healthy men (mean age 29 years) participated in a double-blind crossover study for 11 weeks with propranolol, atenolol, and placebo. Maximal exercise tests were done at baseline and after placebo and beta-blockade phases. Blood for analysis was collected via indwelling brachial vein angiocatheters at baseline and during and after testing. Plasma potassium and magnesium levels increased at peak exercise with atenolol, propranolol, and placebo. There was no difference among groups in baseline recovery for magnesium (mean 28 minutes, range 24 to 30 minutes). Potassium levels returned to baseline more rapidly (compared with magnesium) in the placebo and atenolol groups (mean 10 minutes); however, recovery time was prolonged with propranolol (26 minutes) compared with placebo and atenolol (p less than 0.01). In conclusion, plasma magnesium and potassium levels increased significantly with maximal exercise and are unaffected by atenolol or propranolol beta-blockade. Propranolol, however (compared with atenolol and placebo), prolongs the time of return to baseline of plasma potassium after exercise.

Effects of exercise testing, training and beta blockade on serum potassium in normal subjects

To evaluate the effects of exercise testing, training and beta blockade on serum potassium, 40 normal subjects (24 men, 16 women, mean age 33 years) had 4 maximal exercise tests with venipuncture for serum potassium before and less than or equal to 40 seconds after each test. After initial exercise testing, they were randomized to atenolol 50 mg daily, atenolol 100 mg daily, propranolol 80 mg twice daily or placebo. All began a 9-week dynamic exercise program for 8 weeks followed by a 1-week drug-free washout period. Tests were done after weeks 1, 8 and 9. A significant mean increase (p less than 0.05) in serum potassium occurred with maximal exercise in the atenolol 50 mg and propranolol groups after 1 week of treatment (mean +/- standard deviation, 4.78 +/- 0.29 to 5.09 +/- 0.43 mEq/liter and 4.81 +/- 0.55 to 5.30 +/- 0.33 mEq/liter). By week 8 after training, all beta blockade groups showed an increase in postmaximal exercise test serum potassium (atenolol 50 mg, 4.78 +/- 0.29 to 5.11 +/- 0.26 mEq/liter; atenolol 100 mg, 4.95 +/- 0.41 to 5.16 +/- 0.36 mEq/liter; propranolol, 4.81 +/- 0.55 to 5.05 +/- 0.29 mEq/liter). After washout, only the placebo group showed an increase in postmaximal test serum potassium (4.99 +/- 0.46 to 5.35 +/- 0.27 mEq/liter). Data indicate that hyperkalemia with maximal exercise testing increases after training with atenolol and propranolol compared to placebo and that this effect resolves once treatment is discontinued.

Exercise Testing and Training in Physically Disabled Men With Clinical Evidence of Coronary Artery Disease

A prospective, randomized, controlled clinical trial in patients with coronary artery disease (CAD) and a concurrent physical disability evaluated the effects of a home exercise training program on cardiovascular function and blood lipids. Eighty-eight men between the ages of 42 and 72 years (mean 62) with documented CAD and a physical disability with functional use of > or = 2 extremities including 1 arm were randomized to either a 6-month home exercise training program using wheelchair ergometry or to a control group that received usual and customary care. Both groups received dietary instructions and were requested to follow a fat-controlled diet. Exercise test variables with echocardiography and blood lipids were measured at baseline and at 6 months. The home exercise training group significantly improved both peak exercise left ventricular ejection fraction (p = 0.007) and fractional shortening (p = 0.01) between baseline to 6 months, whereas the control group showed no significant changes. Exercise training effects of decreased resting heart rate (p = 0.03) and decreased peak rate pressure product (p = 0.03) were also found in the treatment group. No exercise-related cardiac complications occurred. Both groups significantly (p < or = 0.01) increased high-density lipoprotein cholesterol levels. These results indicate that physically disabled men with CAD can safely participate in a home exercise training program which may result in intrinsic cardiac benefits. The metabolic cost of activities of daily living imposed on this disabled population may also have a positive effect on high-density lipoprotein cholesterol levels.