Cardiac rehabilitation as secondary prevention. Agency for Health Care Policy and Research and National Heart, Lung, and Blood Institute

This Quick Reference Guide for Clinicians highlights the conclusions and recommendations from Cardiac Rehabilitation, Clinical Practice Guideline No. 17, which was formulated by a panel representing the major health care disciplines involved in cardiac rehabilitation. The conclusions and recommendations were derived from an extensive and critical review of the scientific literature pertaining to cardiac rehabilitation, as well as from the expert opinion of the panel. This guide addresses the role of cardiac rehabilitation and the potential benefits to be derived in the comprehensive care of the 13.5 million patients with heart disease in the United States, as well as the 4.7 million patients with heart failure and the several thousand patients undergoing heart transplantation. This Quick Reference Guide for Clinicians highlights the major effects of multifactorial cardiac rehabilitation services: medical evaluation; prescribed exercise; cardiac risk factor modification; and education, counseling, and behavioral interventions. The outcomes of and recommendations for cardiac rehabilitation services are categorized as to their effects on exercise tolerance, strength training, exercise habits, symptoms, smoking, lipids, body weight, blood pressure, psychological well-being, social adjustment and functioning, return to work, morbidity and safety issues, mortality and safety issues, and pathophysiologic measures. Patients with heart failure and after cardiac transplantation, as well as elderly patients, are specifically addressed. Alternate approaches to the delivery of cardiac rehabilitation services are presented.

Wortmannin and LY294002 inhibit the insulin-induced down-regulation of IRS-1 in 3T3-L1 adipocytes

The insulin receptor substrate-1 (IRS-1) is expressed in 3T3-L1 adipocytes and is involved in at least some insulin responses, notably mitogenesis. Chronic exposure to insulin down regulates IRS-1 in these cells by stimulating its degradation (Rice, K.M., Turnbow, M.A. and Garner, C.W. (1993) Biochem. Biophys. Res. Commun. 190, 961-967). This insulin response was completely inhibited by wortmannin and LY294002 (2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one), two inhibitors of phosphatidylinositol 3-kinase (PI 3-kinase). Neither wortmannin nor LY294002 had any effect on the calcium-dependent degradation of IRS-1 in vitro nor did they inhibit the phosphorylation of IRS-1 in vitro. In addition, neomycin, a cationic aminoglycoside antibiotic that binds to phosphoinositides, inhibited the insulin-induced down-regulation of IRS-1 in 3T3-L1 adipocytes and, also, the C8-PIP3-stimulated degradation of IRS-1 in vitro. These results suggest that PI 3-kinase and its 3-phosphoinositide products mediate the insulin-induced down-regulation of IRS-1 in 3T3-L1 adipocytes.

Parents' views of health surveillance

The aim of the study was to discover the views of parents about the 1991 Leicestershire child health surveillance programme, its organisation, and content. The study design was a postal questionnaire survey to parents of a sample of children eligible for the new surveillance programme. One thousand parents received questionnaires, of which 66% (660) were returned. Poor access for prams and wheelchairs (595 responses) and inadequate general cleanliness (249 responses) caused most criticism of clinic premises. The experiences of parents from ethnic minorities were significantly worse for some professional consultation factors, but they received significantly more health advice than other parents. Parents lacked sufficient information about the surveillance programme and their most frequent reasons for non-attendance were time related factors. Minimum standards for child health surveillance premises are required. At present, many fail to reach adequate standards of privacy and accessibility. Schemes to ensure an equal partnership in child health surveillance between parents and professionals are essential.

The oxazolidinedione CP-92,768-2 partially protects insulin receptor substrate-1 from dexamethasone down-regulation in 3T3-L1 adipocytes

Oxazolidinediones are a class of oral antidiabetic agents that are closely related structurally and pharmacologically to thiazolidinediones. The thiazolidinediones have been shown to partially reverse the loss in insulin-responsive glucose uptake caused by chronic treatment with dexamethasone. This study was conducted to determine certain aspects of the mechanism of thiazolidinedione and oxazolidinedione action. We selected the oxazolidinedione CP-92,768-2 (5-[2-[(5-methyl2-phenyl-4-oxazolyl)methyl]5-benzofuranyl methyl]2,4- oxazolidinedione) to determine whether these agents could reverse the dexamethasone-induced down-regulation of IRS-1, the insulin receptor substrate-1. In 3T3-L1 adipocytes, dexamethasone treatment resulted in down-regulation of IRS-1 to 60% of control values. Simultaneous treatment with CP-92,768-2 significantly increased IRS-1 to 78% of the control value (EC50, < 10 nM), although it did not completely reverse the dexamethasone effect at any concentration tested. CP-92,768-2 alone did not have any effect on IRS-1. CP-92,768-2 did not affect the stability of IRS-1 protein in the presence or absence of dexamethasone, as measured by [35S]methionine pulse-chase labeling. Dexamethasone decreased messenger RNA (mRNA) for IRS-1 after 24 h of treatment to 40% of the control value. CP-92,768-2 partially reversed this decrease in IRS-1 mRNA to 65% of the control value after 24 h of treatment, but had no effect on IRS-1 mRNA in the absence of dexamethasone. Dexamethasone down-regulated the insulin stimulation of [3H]thymidine incorporation to 68% of the control value. Dexamethasone in the presence of CP-92,768-2 down-regulated insulin stimulation of thymidine incorporation by only 9%. Dexamethasone also down-regulated the expression of phosphoenolpyruvate carboxykinase (PEPCK) protein by 50%. CP-92,768-2 partially protected PEPCK from the dexamethasone down-regulation. Conversely, the up-regulation of expression of PEPCK and IRS-1 produced by dexamethasone in KRC-7 hepatoma cells was not affected by CP-92,768-2. One contribution of oxazolidinediones to an increase in insulin responsiveness in the presence of glucocorticoids may be the up-regulation of IRS-1 in adipose cells.

Factors affecting treatment compliance in amblyopia

Amblyopia is the most common form of visual disability in children. Successful treatment by patching depends on compliance, but evidence of factors affecting compliance is limited and contradictory. Because there is a well established relationship between social deprivation and access to health care, we hypothesized that social deprivation might be associated with noncompliance. Data from a historical cohort of 961 children from seven English orthoptic clinics starting treatment for amblyopia in 1983 were used to study factors affecting compliance with amblyopia treatment. Children were classified as noncompliant if they failed to attend all appointments prescribed during the first year of treatment. There was a significant difference in compliance between centers (P = .0001). Overall, children with anisometropic amblyopia were more compliant than those with strabismus but this varied significantly between centers. A relationship between social deprivation and compliance was also found (P = .00001). Only 41% of children from the most deprived wards were compliant compared with 61% in the least deprived wards. Compliance was not found to be related to age at starting treatment.

Matching for MHC haplotypes results in improved survival following unrelated bone marrow transplantation

Unrelated bone marrow donor-recipient pairs were assessed retrospectively for matching of the HLA-B, -C region (beta-block) and HLA-DR, DQ region (delta block) of the major histocompatibility complex (MHC) using a new DNA-based method referred to as MHC-block typing. The method utilises non-HLA DNA polymorphisms in the MHC as markers of blocks of ancestral haplotypes. Kaplan-Meier analysis of recipients who were matched at both the beta- and delta-blocks revealed a 6 months survival of 54%. Survival was better than for patients who were matched only by conventional criteria, including SSO-typing for class II.

Stair climbing elicits a lower cardiovascular demand than walking in claudication patients

PURPOSE

Peripheral arterial disease patients limited by claudication pain frequently have concomitant-cardiovascular problems during exercise, such as hypertension and myocardial ischemia. Thus, for testing and rehabilitation purposes, exercise which elicits lower heart rate and blood pressure at a given metabolic intensity would be preferred over a more demanding task. The purpose of this study was to compare the cardiovascular responses of claudication patients during walking and stair climbing at a similar level of oxygen uptake.

METHODS

Ten patients limited by claudication pain performed treadmill walking and stair climbing tests.

RESULTS

Oxygen uptake was similar (P > .05) during walking and stair climbing (13.7 vs. 13.5 mL/kg/min, respectively). The times to onset and to maximal claudication pain, as well as the peripheral hemodynamic measurements of ankle systolic pressure, ankle-to-brachial systolic pressure index, and foot transcutaneous oxygen tension were also similar between the two tests (P > .05). However, heart rate, systolic pressure, diastolic pressure, mean arterial pressure, and rate-pressure product values were lower during and following stair climbing than compared to walking (P < .05).

CONCLUSION

Stair climbing may offer an advantage over treadmill walking for claudication patients because similar metabolic, claudication, and peripheral hemodynamic measurements are obtained with concomitantly less demand placed on the cardiovascular system. The stair climbing test was well tolerated and safely performed by each patient.

Factors affecting the outcome of children treated for amblyopia

The outcome of treatment for amblyopia and the factors that affect this are not well understood. A major reason for this has been the exclusion from previous large studies of a sometimes unknown number of patients because of failure to comply with treatment. This paper analyses the outcome of amblyopia treatment in a retrospective review of the orthoptic records of a cohort of 961 children treated for amblyopia at seven centres who first attended in 1983. The final visual acuity was recorded by Snellen or matching methods in 894 children (93%). Of these, 48% achieved 6/9 or better, 35% less than 6/9 but better than or equal to 6/18, and 17% achieved less than 6/18. The outcome was best for pure anisometropic amblyopia, intermediate for pure strabismic amblyopia and least good for mixed strabismic and anisometropic amblyopia with a final visual acuity of 6/10.2, 6/12.8 and 6/14.8 respectively. While the age at start of treatment did not correlate with final visual acuity both poor initial visual acuity and poor compliance were associated with poor outcome. The main factor affecting the outcome of amblyopia treatment is the initial visual acuity. Comparison with the literature suggests that the results of treatment in this country may be falling far short of what would be possible in ideal circumstances with unlimited resources.

The presentation of children with amblyopia

This study reports the presentation of 961 children who underwent amblyopia treatment at seven orthoptic centres in the United Kingdom. We confirmed previous authors' findings of a small but significant increased incidence of left-sided compared with right-sided amblyopia overall. For pure anisometropic amblyopia this difference was very marked and a possible pathophysiological mechanism is proposed. The mean age of presentation for anismetropic, strabismic and mixed amblyopia was 5.6, 3.3 and 4.4 years, respectively. Neither sex nor race affected the age of presentation. Despite their older age, children with pure anisometropic amblyopia had the best initial visual acuity, with 25% of anisometropes having an initial visual acuity of less than 6/18 compared with 39% of strabismics and 50% of mixed amblyopes. The ages and initial acuities of the strabismic patients in this series are at least as favourable as those of patients reported from outside the UK. There were variations in the age and proportion of patients presenting with anisometropic amblyopia at the different centres, suggesting a failure in the referral of anisometropic amblyopia of importance in interpreting epidemiological studies.

Social deprivation and age at presentation in amblyopia

BACKGROUND

Amblyopia is the most common visual disability in children. Early treatment is thought to be more effective, and therefore factors affecting the age at presentation are important. A relationship between social deprivation and access to health care and screening services is well known. We hypothesized that social deprivation might be associated with later presentation of amblyopia, particularly of anisometropic amblyopia which depends on vision screening for referral.

METHODS

Data from a historical cohort of 897 children with amblyopia, from seven UK orthoptic clinics, were used to test this hypothesis. Social deprivation was measured by the Townsend score of the ward in which the child lived.

RESULTS

A relationship between social deprivation and age at presentation was found in children with anisometropic amblyopia even after adjusting for differences between clinics (p = 0.01) but no similar association was evident in children with amblyopia associated with strabismus. There was a difference of 22 months in the average age at presentation between children with anisometropic amblyopia in the most deprived and least deprived areas of the study.

CONCLUSIONS

If screening for anisometropic amblyopia is to be undertaken, priority should be given to screening children from areas of social deprivation.

Properties of Cr:LiSrAIF(6) crystals for laser operation

We have performed several physical and optical measurements on the Cr:LiSAF (LiSrAlF(6)) laser material that are relevant to its laser performance, including thermal and mechanical properties, water durabilities, and Auger upconversion constants. The expansion coefficient, Young's modulus, fracture toughness, thermal conductivity, and heat capacity are all used to determine an overall thermomechanical figure of merit for the crystal. An investigation of the water durability suggests that the cooling solution should be maintained at pH = 7 to ameliorate problems associated with water dissolution. The Auger constant was found to become much more significant at higher Cr doping, in which excited-state migration leads to a substantial increase in the upconversion rate. We propose a design for a 50-W Cr:LiSAF laser system that is based on a detailed knowledge of all the relevant material parameters.

Safety and compatibility of betaxolol hydrochloride combined with diltiazem or nifedipine therapy in stable angina pectoris

Compared with placebo, adding betaxolol 20 mg every day to nifedipine (up to 60 mg/day in divided doses) or diltiazem (up to 360 mg/day in divided doses) for a 3-week treatment period in 135 patients with stable angina pectoris significantly (p < 0.05) lengthened the time to onset of moderate angina during exercise tolerance tests at all treatment time points. The median increases in the time to onset of moderate angina at the final exercise tolerance test (end point) compared with baseline were 1.08 and 0.53 minutes for betaxolol and placebo groups, respectively (p = 0.002, betaxolol and placebo groups, respectively (p = 0.002, betaxolol vs placebo). The time to onset of 1 mm ST-segment depression increased significantly (p < 0.05) with betaxolol compared with placebo at all but 1 treatment time point (median increase [p = 0.001] 1.77 and 0.37 minutes, respectively, at end point). Duration of exercise also was increased significantly (p < 0.05) after the third week of treatment and at end point (median 0.62 and 0.50 minutes, respectively; p = 0.03). Generally comparable results were found within the diltiazem (n = 128) and nifedipine (n = 25) subgroups, although the nifedipine group was too small to detect statistically significant differences between betaxolol and placebo treatment. Resting systolic blood pressure, heart rate and the rate-pressure product, measured both when angina occurred and at the end of exercise, also were influenced significantly (p < 0.05) by the betaxolol addition. The only serious adverse effect associated with betaxolol treatment was syncope, seen in 2 patients.

The insulin receptor substrate (IRS-1) is a PEST protein that is susceptible to calpain degradation in vitro

The insulin receptor substrate 1 (IRS-1) contains at least 11 sequence motifs that are rich in proline (P), glutamic acid (E), serine (S), and threonine (T), i.e., PEST regions. Proteins with PEST regions turn over rapidly. IRS-1 is degraded rapidly in vivo upon exposure of 3T3-L1 adipocytes to insulin. The intracellular, calcium-dependent, neutral proteases known as calpains are one possible mechanism by which IRS-1 may be degraded. To begin to investigate this possibility, purified exogenous calpain was shown to degrade IRS-1 in cell-free extracts from basal and insulin-treated cells and rat recombinant IRS-1 in vitro. Only two proteolytic fragments could be detected. One had a mol wt of approximately 79 kDa, arising from the C-terminus end, and the second had a mol wt of approximately 90 kDa arising from near the N-terminus, possibly a product of the same cleavage event, since the mol wt of IRS-1 from insulin-treated cells was approximately 170 kDa. These results suggest that IRS-1 may serve as a substrate for calpain in vivo, accounting for its rapid degradation.

Histocompatibility matching for bone marrow transplantation. Donor-recipient pairs in the 4AOHW cell panel

While the results of unrelated bone marrow transplantation are continually improving, a number of important issues remain: what are the histocompatibility requirements, what genes are involved, what mismatches are acceptable, and what are the best methods for determining donor-recipient match? In this study of material provided through the 4AOHW and the US NMDP, the match between 53 donor-recipient pairs was determined using several different markers within the MHC. The data showed that many apparently well-matched pairs have many mismatches, including mismatches for non-HLA genes (i.e., non-class-I or non-class-II) within the MHC. New methods matching for blocks of DNA around HLA-B and around HLA-DR/DQ are available that are sensitive and identify additional mismatches that are not apparent using conventional typing methods. The 4AOHW cells provide a valuable resource for the comparison and assessment of new matching techniques.

Withdrawal of digoxin from patients with chronic heart failure treated with angiotensin-converting-enzyme inhibitors. RADIANCE Study

BACKGROUND

Although digoxin is effective in the treatment of patients with chronic heart failure who are receiving diuretic agents, it is not clear whether the drug has a role when patients are receiving angiotensin-converting-enzyme inhibitors, as is often the case in current practice.

METHODS

We studied 178 patients with New York Heart Association class II or III heart failure and left ventricular ejection fractions of 35 percent or less in normal sinus rhythm who were clinically stable while receiving digoxin, diuretics, and an angiotensin-converting-enzyme inhibitor (captopril or enalapril). The patients were randomly assigned in a double-blind fashion either to continue receiving digoxin (85 patients) or to be switched to placebo (93 patients) for 12 weeks. Otherwise, their medical therapy for heart failure was not changed.

RESULTS

Worsening heart failure necessitating withdrawal from the study developed in 23 patients switched to placebo, but in only 4 patients who continued to receive digoxin (P < 0.001). The relative risk of worsening heart failure in the placebo group as compared with the digoxin group was 5.9 (95 percent confidence interval, 2.1 to 17.2). All measures of functional capacity deteriorated in the patients receiving placebo as compared with those continuing to receive digoxin (P = 0.033 for maximal exercise tolerance, P = 0.01 for submaximal exercise endurance, and P = 0.019 for New York Heart Association class). In addition, the patients switched from digoxin to placebo had lower quality-of-life scores (P = 0.04), decreased ejection fractions (P = 0.001), and increases in heart rate (P = 0.001) and body weight (P < 0.001).

CONCLUSIONS

These findings indicate that the withdrawal of digoxin carries considerable risks for patients with chronic heart failure and impaired systolic function who have remained clinically stable while receiving digoxin and angiotensin-converting-enzyme inhibitors.

Comparison of treadmill walking and stair climbing over a range of exercise intensities in peripheral vascular occlusive disease

Although claudication pain and hemodynamic responses to exercise are related to the degree of arterial narrowing in the lower extremities, the nature of these responses to different exercise tasks and intensities is less clear. Thus, the purpose of this study was to compare claudication and hemodynamic responses to graded walking, level walking, and stair climbing over a range of exercise intensities. Ten patients with peripheral vascular occlusive disease performed five tests within each of the three exercise tasks. Similar values of oxygen consumption were obtained among exercise tasks at each intensity (p = ns). Time to onset of claudication pain and to maximal pain were similar among exercise tasks (p = ns), and both demonstrated a curvilinear decrease as intensity increased (p < 0.05). Foot transcutaneous oxygen tension, ankle systolic blood pressure, and ankle/brachial systolic pressure index were also similar among the three exercise tasks (p = ns); however, each decreased linearly as exercise intensity increased (p < 0.05). Thus, in peripheral vascular occlusive disease, the imbalance between oxygen delivery to the exercising lower extremity musculature and the local metabolic demand is similar during different weight-bearing activities. Second, even though the peripheral circulation is progressively impaired with increased exercise intensity, anaerobic metabolism in the ischemic lower extremity musculature may prevent a continual decline in claudication times. The clinical implication is that a more thorough assessment of the functional limitations imposed by claudication pain is not obtained by using different types of weight-bearing exercise tests as opposed to using on ly one type.

Membrane-bound choline-O-acetyltransferase in rat hippocampal tissue is anchored by glycosyl-phosphatidylinositol

In an earlier study, we presented evidence to suggest that some of the particulate choline-O-acetyltransferase (ChAT) in rat hippocampal tissue might be linked to membranes by a glycosyl-phosphatidylinositol (GPI) anchor. In the present report, we attempted to determine if any of this GPI-anchored ChAT might be intracellular. Internalization of phosphatidylinositol-specific phospholipase C (PI-PLC) from Bacillus thuringiensis into rat hippocampal synaptosomes by the DMSO (dimethyl sulfoxide) freeze/thawing procedure caused an increase in cytosolic and a decrease in membrane-bound ChAT. Incubation of a plasma membrane enriched subcellular fraction at 16 degrees C relative to 4 degrees C led to a conversion of the membrane-bound, amphiphilic ChAT into hydrophilic ChAT. This conversion was blocked by zinc, an inhibitor of GPI-PLC. The cytosolic fraction of ChAT immunoreacted on western blots with an antibody directed against the cross-reacting determinant (CRD) of the GPI anchor. We suggest that some of the membrane-bound ChAT in rat hippocampal tissue is GPI-anchored intracellularly; also, that an endogenous GPI-PLC-like enzyme acts to release it into the cytosol.

Medical treatment after myocardial infarction. Results of studies using various methods

Patients who have had myocardial infarction and are at risk for continued problems may benefit from several treatment methods (table 1). Beta-adrenergic blockers reduce subsequent cardiovascular morbidity and mortality through their effect on the myocardial supply-demand balance. Administration of angiotensin-converting enzyme inhibitors reduces morbidity and mortality rates in myocardial infarction survivors who have diminished left ventricular ejection fraction. Aspirin and other anticoagulants are beneficial through their antiplatelet effects. Cardiac rehabilitation methods and aggressive management of lipids levels are also useful.

Comparison of three progressive exercise protocols in peripheral vascular occlusive disease

Although claudication pain and hemodynamic responses to exercise are usually clinically assessed via graded treadmill walking, measuring these responses to other commonly performed tasks may yield a more nearly complete evaluation of peripheral vascular occlusive disease. Thus, the purpose of this study was twofold: (1) to determine the reliability of claudication and hemodynamic responses to level walking and stairclimbing and (2) to compare these responses with those obtained with graded walking at similar oxygen consumption. Ten patients with stable claudication symptoms performed graded walking, level walking, and stairclimbing progressive protocols with respective increases in grade, walking speed, and stepping rate on a modified stairclimbing device every two minutes. Similar peak oxygen consumption (13.60 to 14.18 mL/kg/min) was attained with the three protocols (P = NS). Reliability coefficients for the times to onset and to maximal claudication pain during level walking (R = 0.95 and 0.95, respectively) and during stairclimbing (R = 0.92 and 0.82, respectively) were similar to those previously obtained during graded walking. Reliability coefficients for foot transcutaneous oxygen tension during and following level walking (R = 0.78 to 0.96) and stairclimbing (R = 0.65 to 0.98) and for ankle systolic blood pressure following level walking (R = 0.95 to 0.97) and stairclimbing (R = 0.90 to 0.98) were also similar to those previously found with graded walking. Additionally, claudication and hemodynamic measurements were similar among the three exercise protocols. Thus, because graded walking, level walking, and stairclimbing progressive exercise protocols yield reliable and similar information about the hemodynamic severity of peripheral vascular occlusive disease, only one is needed for evaluation.

Prediction of claudication pain from clinical measurements obtained at rest

The ability to predict claudication pain during single-stage (S) and progressive (P) treadmill protocols from clinical measurements obtained at rest was examined. Peripheral hemodynamic measurements from the more severely diseased lower limb and medical history data were obtained from 56 claudicant patients during supine rest immediately preceding S (1.5 mph and 7.5% grade) and P (2 mph, 0% grade with 2% increase every 2 min) treadmill protocols. Distance walked to onset of claudication pain (CPD) and to maximal pain (MPD) during both protocols were recorded. The claudication distances during the S protocol were not correlated with either the peripheral hemodynamic or medical history variables. In contrast, CPD and MPD during the P protocol were predicted (P less than 0.05) by ankle/brachial systolic blood pressure index (ABI) (quadratic relationship), laterality of claudication pain (1 = unilateral, 2 = bilateral), and gender (1 = female, 2 = male) from the following regression equations: CDP (m) = 159.9 - (321.8 x ABI) + (445.6 x ABI2) - (93.5 x laterality) + (99.0 x gender), R = 0.74, R2 = 0.55, adjusted R2 = 0.53, SEE = 110.5, P less than 0.0001; and MPD (m) = 83.1 + (195.0 x ABI) + (174.0 x ABI2) - (76.4 x laterality) + (114.2 x gender), R = 0.76, R2 = 0.58, adjusted R2 = 0.55, SEE = 138.3, P less than 0.0001. It is concluded that the regression equations for the prediction of CPD and MPD may be used to quickly estimate the functional severity of peripheral vascular occlusive disease in clinical settings where treadmill testing is not feasible or is impractical.

Effects of handrail support on claudication and hemodynamic responses to single-stage and progressive treadmill protocols in peripheral vascular occlusive disease

Because handrail support reduces the energy cost of treadmill walking, claudication and hemodynamic responses of patients with peripheral vascular occlusive disease should also be affected. Furthermore, the reliability of the test results may be reduced unless the same pressure is applied to the handrails over repeated tests. The effect of handrail support on claudication and hemodynamic responses, and on their reliability, were examined during single-stage (2 mph, 12% grade) and progressive (2 mph, 0% grade with 2% increase every 2 minutes) treadmill protocols. Ten patients with stable disease performed both protocols 3 times, separated by 1 week, with and without handrail support. Claudication pain distance and maximal walking distance were greater (p less than 0.05) when handrail support was permitted, and they increased (p less than 0.05) over repeated tests of each protocol. No increase was noted over the tests without support. The responses and reliability of foot transcutaneous oxygen tension, ankle systolic pressure and ankle/brachial systolic pressure index after exercise to maximal tolerable pain were not affected by handrail support. Because claudication distances were altered, it is concluded that handrail support should not be allowed when assessing claudicants, unless balance cannot otherwise be maintained.

Relationship between foot transcutaneous oxygen tension and ankle systolic blood pressure at rest and following exercise

To determine whether foot transcutaneous oxygen tension (TcPO2) and ankle systolic blood pressure (SBP) measure similar aspects of peripheral vascular occlusive disease (PVOD), the authors examined their relationship at rest and following treadmill exercise. Thirty-seven PVOD patients (mean age 69.2 +/- 0.8 years) rested supine for twenty minutes, followed by a progressive treadmill walking test at a constant speed of 2 mph. The initial grade was 0%; this increased 2% every two minutes until maximal claudication pain (n = 19) or until the occurrence of such limiting symptoms as volitional fatigue (n = 6), ST segment depression (n = 4), dyspnea (n = 3), multiple premature ventricular contractions (n = 2), and angina (n = 2). Patients then rested supine for fifteen minutes. Foot TcPO2 was recorded before, during, and after exercise, whereas ankle SBP was measured before and after exercise. At rest, a curvilinear relationship was found between foot TcPO2 and ankle SBP (foot TcPO2 = 41.89 + 0.22(ankle SBP) + 0.0005 (ankle SBP2); SEE = 9.2, R = 0.64, R2 = 0.41, p less than 0.001). In contrast, the relationship was stronger and more linear during recovery, particularly at the sixth minute (foot TcPO2) = 8.33 + 0.35 (ankle SBP); SEE = 13.6, R = 0.86, R2 = 0.73, p less than 0.001). At rest, foot TcPO2 and ankle SBP characterized different aspects of PVOD because they shared only 41% common variance. During recovery, they provided similar information because up to 73% of the variance was shared. It is concluded that foot TcPO2 should also be used to assess PVOD patients because unique information is obtained at rest and values can be recorded during exercise.

Exercise training in patients with impaired left ventricular function

Advances in the understanding of the pathophysiology of congestive heart failure have guided efforts in formulating effective treatment strategies. The epidemiology, etiology, and medical management of congestive failure are reviewed. The changing approaches to exercise and exercise training in patients with heart failure are discussed. Recent studies of the impact of exercise training in this important patient group are presented.

Progressive vs single-stage treadmill tests for evaluation of claudication

The reliability of claudication pain and the metabolic and hemodynamic measurements of the lower limbs of patients with stable peripheral vascular occlusive disease (PVOD) were compared during and following single-stage (S) and progressive (P) treadmill tests. Ten patients (69.8 +/- 1.8 yr; X +/- SE) walked to maximal claudication pain twice a month for 4 months. Patients walked at 1.5 mph up a 7.5% grade (S test) and at 2 mph on a 0% grade, increasing by 2% every 2 min (P test). Distance walked to the onset of claudication pain (CPD) and maximal walking distance (MWD) were recorded. Foot transcutaneous oxygen tension (TcPO2) was measured before, during, and after exercise, while ankle systolic blood pressure (SBP) and the ankle-to-brachial SBP index (ABI) were measured before and after exercise. Intraclass correlation coefficients (R) of CPD and MWD during S tests were R = 0.53 and R = 0.55, respectively. In contrast, the respective R values during P tests were R = 0.89 and R = 0.93. Higher R values of foot TcPO2 were also obtained during and following P tests, while ankle SBP and ABI were highly reliable following both tests. It is concluded that the severity of PVOD is better assessed by P treadmill tests because clinical measurements are more reliable during exercise and recovery.