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Biomedical subjects

G F Fletcher

Publications and source records attributed to G F Fletcher.

At least 37 records · Page 2Linked to original sources
PubMed1994

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.

Adult↗
PubMed1994

Design of the training levels comparison trial.

The Training Levels Comparison (TLC) trial was a grant-supported, multicenter, randomized, controlled clinical trial designed to determine whether cardiac rehabilitation patients would benefit from supervised exercise for a prolonged period (2 years) and whether subjecting patients to a more vigorous exercise program than currently recommended would provide additional cardiac benefit. If high-intensity exercise does not enhance the cardiac benefit, then physical activity should be limited to low-intensity levels that are safer, easier to implement and more adaptable to a greater number of patients. Patients were randomly assigned to either a low-intensity or high-intensity training program. All patients were to attend three 1-hour supervised exercise sessions per week for a period of 2 years. Attendance at exercise sessions and adherence to assigned treatments were monitored throughout the study. Patients were evaluated for outcome measures at 3, 6, 12, and 24 months. This paper reports the study design and methodology for the TLC trial, and should be useful in providing methodologies to facilitate comparison of data from other studies with different levels of exercise as an intervention.

Adult↗
PubMed1994

Exercise in the prevention of stroke.

Lifestyle and behaviour modifications that include exercise are effective in the prevention of cardiovascular disease and stroke. The benefits are manifested largely through the role that exercise plays in the control of certain modifiable risk factors, such as control blood lipid abnormalities, diabetes and obesity. Exercise also adds an independent effect in the lowering of blood pressure in certain hypertensive groups, thus favourably modifying a major risk factor for stroke. The Honolulu Heart Program, a 22 year follow-up of 5,362 men (aged 58 to 68) revealed that physical activity was protective against "clot caused" stroke only in nonsmokers. This study also revealed that inactive and partially active men compared with those who were active had fourfold increases in intracerebral hemorrhage and threefold increases in subarachnoid hemorrhage. The Framingham study suggested a relationship between sedentary work and stroke although this was not statistically significant. In a 16-year follow-up of 3,263 cargo handlers the death rate from stroke was similar to that of more sedentary people. However, the mortality was threefold higher among those who were sedentary and had higher systolic blood pressure. The exercise employed in prevention can be mild to moderate in intensity and may be of the type experienced in occupational, recreational and leisure time activity. Clinical data reveal that aerobic exercise equal to or greater than 50% of one's maximum capacity can be "protective" in cardiovascular disease.

Aged↗
PubMed1993

Cardiac precautions for non-acute inpatient settings.

Activity progression of persons with physical disabilities and accompanying cardiovascular disease in medical rehabilitation centers is traditionally based on cardiac precautions derived from acute care settings. Concern that these guidelines were too conservative and restrictive led to exercise testing and evaluation of 64 physically disabled male patients with a history of coronary artery disease. The sample had a mean age of 62.4 years. The exercise test was an adaptation of the Schwade Arm Ergometer Protocol with blood pressure measured at baseline, immediately after each 2 minutes of exercise, peak exercise and each minute for 6 minutes after peak exercise. Heart rate was monitored continuously. Patients achieved a mean peak heart rate of 115 beats per minute, mean peak systolic pressure of 169 mm Hg and mean peak diastolic pressure of 89 mm Hg. Ischemic electrocardiographic changes occurred in four of the 64 patients. Based on the achieved ranges of values of heart rate, systolic and diastolic pressures and comparison of these results with baseline (pre-exercise) values, more liberal guidelines for prescribing activity in the non-acute inpatient setting are provided.

Adult↗
PubMed1993

Rehabilitative exercise for the cardiac patient. Early phase.

The early phase of cardiac rehabilitation provides an opportunity for patient education and coronary risk factor modification with exercise training. In addition, a diagnostic evaluation can be performed from the vantage of detecting changes in myocardial ischemia, heart rate, and rhythm, particularly in the monitored phase. During this early phase of cardiac rehabilitation, an extension of the evaluation of each patient can be performed before he or she begins more independent types of cardiac rehabilitation with less professional supervision. When these early phases of rehabilitation are properly carried out, the education and diagnostic components can be maximized for the patient and, thus, aid in stabilizing therapy before the patient is allowed freedom in the rehabilitative process or the opportunity of individually performing in a self-monitored program.

Adult↗
PubMed1991

Blood magnesium and potassium alterations with maximal treadmill exercise testing: effects of beta-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.

Adrenergic beta-Antagonists↗
PubMed1991

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.

Adult↗
PubMed1990

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.

Adult↗
PubMed1989

Exercise testing and training with beta-adrenergic blockade: role of the drug washout period in "unmasking" a training effect.

To determine whether or not a training effect can be achieved with beta-adrenergic blockade and whether there is a difference between selective and nonselective therapy, we recruited 40 healthy subjects (16 women, 24 men) to participate in a 9-week exercise training program. After a baseline exercise treadmill test, subjects were randomized to oral therapy groups of atenolol, 50 mg daily (AT 50), atenolol, 100 mg daily (AT 100), propranolol, 80 mg twice a day (Prop), or placebo. Repeat exercise tests were performed at week 1, week 8, and at week 9, with week 8 to 9 being a 1-week drug-free washout period. At week 8, maximal oxygen consumption (Max VO2), when compared with baseline levels, was increased slightly in AT 50 (4.2%) and Prop (2.4%), decreased in AT 100 (5.3%), and increased significantly in the placebo group (12.7%). After washout, Max VO2 increased significantly compared with baseline in AT 50, AT 100, and Prop (9.8%, 10.8%, and 9.8%, respectively). We conclude that there is no significant difference between selective and nonselective beta-blockade therapy in the development of a training effect. This effect, however, may not become apparent until the drug is withdrawn.

Adrenergic beta-Antagonists↗
PubMed1988

Exercise testing in patients with musculoskeletal handicaps.

To determine safe and effective exercise testing techniques for musculoskeletally handicapped individuals, 20 patients (mean age, 61 years) were studied. Types of handicaps included various degrees of paralysis of arms and legs, and leg amputations. Seventeen of the 20 patients had concurrent cardiovascular problems. All were currently hospitalized, engaged in various physical therapy exercises, and referred for exercise testing to increase rehabilitation therapy or for cardiovascular evaluation. Of 20 tests, arm ergometry was used in 15, leg or combination arm-leg ergometry in four, and treadmill in one. All patients completed testing with mean increases in heart rate (82 to 106 bpm arm, 88 to 125 other) and systolic blood pressure (114 to 127 mmHg arm, 118 to 146 other). Low-grade atrial and ventricular ectopy occurred in eight patients, decrease or plateauing of systolic blood pressure in three, increased diastolic blood pressure in two, and significant (greater than or equal to 1mm) ECG S-T segment displacement in one. With the use of appropriate equipment for each patient, exercise testing can be done safely and effectively in musculoskeletally handicapped individuals.

Adult↗
PubMed1988

Outpatient rehabilitative training in patients with cardiovascular disease: emphasis on training method.

As our ability to evaluate cardiovascular patients expands and direct oxygen consumption measurements are available, exercise prescriptions can be better individualized for each patient. By using basic principles of frequency and duration and specifically basing intensity and progression on percent of maximum oxygen consumption, protocols using various modes of exercise may be defined so that each patient entering cardiovascular training programs will gradually progress. This methodology discussion presents concise progressions for both phase II monitored and phase II nonmonitored medically supervised exercise training. The phase II monitored protocol consists of levels 1 through 6 and is designed to be completed within a minimum of six 1-hour sessions. The phase II nonmonitored protocol consists of levels 7 through 12 and is designed to be completed within 12 weeks. The ultimate goal is for each patient to safely progress to a training level that can be maintained safely and effectively by the patient. A total of 192 patients enrolled in our phase II programs have safely completed both components and are in long-term maintenance programs.

Cardiac Rehabilitation↗
PubMed1986

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.

Adult↗
PubMed1986

Community phase of cardiac rehabilitation.

Although their effects cannot be shown to statistically alter coronary heart disease mortality or morbidity, voluntary health organizations throughout the world clearly play an important role in bringing about favorable changes in the natural history of this disease and in the community phase of its management. In particular, voluntary organizations are able to conduct research surveys and field trials and by so doing favorably influence state health administration. They are able to correct temporary deficiencies in health services, particularly in the form of psychosocial support and cardiac health education. Observers note that the major change in community phase management has occurred with the wider use of coronary bypass surgery since 1975. More objective data, especially relating to psychosocial factors, can be expected when further research (especially the MONICA Study) is completed. Throughout the world, however, existing voluntary health organizations could be more active in the community phase of cardiac rehabilitation. It would seem an area where such organizations could well do more. A challenging question that should be constantly reviewed is 'Can we do more to reduce the effects of invalidism in cardiac patients?'

Australia↗