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Biomedical subjects

K Stainer

Publications and source records attributed to K Stainer.

At least 19 recordsLinked to original sources
PubMed1994

Reduced customary activity in chronic heart failure: assessment with a new shoe-mounted pedometer.

Although many methods exist to assess the degree of incapacity of patients with chronic heart failure during normal daily activities, all have their limitations. In this study we describe a new shoe-mounted pedometer and compare it with body worn pedometers in normal volunteers and in patients with chronic heart failure. Ten young normal healthy volunteers participated in a comparison of the new shoe-mounted device with body born pedometers and counting a direct footfall. Seventeen patients with chronic heart failure and 10 aged-matched healthy elderly subjects participated in a comparison of both pedometers over 7 days. In the young volunteers the shoe-mounted pedometers were more accurate than the body-borne devices. With both pedometers the patients with chronic heart failure had a reduced level of activity compared with the normal volunteers over the 1 week period (P = 0.01). In both the patients and volunteers the shoe-mounted device recorded a higher score than the body borne pedometers (P < 0.01). The electronic shoe mounted pedometers are a more accurate way of assessing customary activity. In patients with chronic heart failure customary activity is substantially reduced compared with fit healthy elderly subjects.

Activities of Daily Living↗
PubMed1993

The effect of lorcainide on arrhythmias and survival in patients with acute myocardial infarction: an example of publication bias.

Ninety-five patients with suspected acute myocardial infarction were randomly allocated on admission to hospital on a double blind basis to treatment with lorcainide, a Class 1C anti-arrhythmic drug, or matching placebo. Treatment was continued for 6 weeks. Twenty-four-hour ECG tape recordings were made immediately on admission, on the sixth or seventh day after admission, and again just before the end of the treatment period. Lorcainide was shown to be an effective anti-arrhythmic agent. The study was not designed to evaluate the effect of lorcainide on survival, but there were nine deaths among the 49 patients treated with lorcainide compared with only one in the patients given placebo. These findings are consistent with the results of the First and Second Cardiac Arrhythmia Suppression trials (CAST and CAST-II). This study was carried out in 1980 but was not published at the time: it now provides an interesting example of 'publication bias'.

Anti-Arrhythmia Agents↗
PubMed1993

The effect of the angiotensin converting enzyme inhibitor, enalapril, on exercise tolerance and abnormalities of limb blood flow and respiratory function in patients with severe heart failure.

Ten patients with severe (NYHAIII) heart failure were compared with 10 age-matched healthy subjects in terms of oxygen uptake and minute ventilation at rest and during exercise and calf and forearm blood flow measured by venous occlusion plethysmography at rest and after a standardized exercise test. Patients performed a symptom-limited treadmill exercise test and were then treated with enalapril for 5 weeks; the various measurements were repeated at weekly intervals. Oxygen consumption (VO2) at rest was similar in the patients and controls. During exercise, patients VO2 tended to be lower at each workload, but this was not affected by enalapril treatment. Minute ventilation was higher at rest and at each exercise stage in the patients than in the control subjects, and this was significantly reduced by enalapril treatment. Compared with the controls (2.94 +/- 0.10 and 2.93 +/- 0.20 ml.100 ml-1.min-1) forearm and calf blood flow measured by venous occlusion plethysmography was reduced at rest in the patients (1.34 +/- 0.18 and 1.24 +/- 0.11 ml.100 ml-1.min-1). but was significantly increased by enalapril treatment (1.73 +/- 0.15 and 1.60 +/- 0.16 ml.100 ml-1.min-1). Submaximal leg exercise to a fixed VO2 showed attenuation of the normal vasoconstriction in the forearm and vasodilatation of the calf; enalapril treatment changed these responses significantly towards normal but a marked abnormality of flow pattern persisted.

Aged↗
PubMed1991

Exercise capability in heart failure: is cardiac output important after all?

The exercise capability of 39 patients with severe chronic heart failure was assessed in several ways and compared with measurements of cardiac output. The relation between cardiac index and exercise tolerance measured on a treadmill was poor (r = 0.191, p = 0.245). However, exercise tolerance measured with a series of self-paced corridor walk tests showed moderate correlations with cardiac index (r = -0.404, p = 0.015 to r = -0.516, p = 0.001) and customary activity assessed by step counting correlated better with cardiac index (r = 0.537, p less than 0.001). Cardiac output therefore seems to be a factor determining patients' exercise capability when they choose their own walking speed but not when they undergo formal treadmill tests in the laboratory.

Aged↗
PubMed1991

Exercise tolerance in patients with heart failure--how should it be measured?

The exercise capability of 12 patients with heart failure was investigated by a variety of different methods before and after treatment with the vasodilator flosequinan. Two treadmill protocols were used, a modified Bruce with incremental workloads and a fixed workload protocol. On placebo, mean exercise time was greater with the Bruce protocol, 526 (64) s, than with the fixed protocol, 359 (59) s, P less than 0.005. Flosequinan increased exercise time more with the fixed protocol, so after 5 weeks' treatment exercise time was the same with both protocols; 680 (64) s with the Bruce and 673 (147) s with the fixed protocol. When the results are expressed as work, the patients achieved less with the Bruce protocol, 7.8 (1.9) kJ, than with the fixed protocol 12.5 (1.5) kJ on placebo, P less than 0.01. After flosequinan, the respective values were 14.5 (2.8) and 25.3 (5.1) kJ. Flosequinan improved corridor walk test times but there was no relationship between this and either treadmill test. Pedometer scores of customary activity were unchanged by flosequinan and were not correlated with any other exercise test. Different methods of assessing exercise capability provide different measures of patients' incapacity.

Clinical Protocols↗
PubMed1991

Post-prandial worsening of angina: all due to changes in cardiac output?

BACKGROUND: The precise mechanism leading to the post-prandial worsening of angina has yet to be adequately defined. It has been attributed to an increase in double product but is perhaps more likely to be related to an increase in cardiac output after food. This study was designed to evaluate the effects of food on patients' exercise tolerance and compare these with changes in haemodynamic variables. METHODS: 23 patients with chronic stable angina who had post-prandial worsening of their angina were studied. The patients were evaluated on two occasions and at each visit they underwent two symptom limited treadmill exercise tests. They remained fasting on the first visit and were given a 1400 kcal meal 60 minutes before the second exercise test on the second visit. Time to onset of 1 mm ST segment depression, heart rate, systemic arterial blood pressure, and cardiac output were measured at rest and during exercise. RESULTS: There were no differences in any of the variables during the two exercise tests on the day the patients remained fasting. After the meal exercise tolerance fell significantly by 136 seconds and the stage at which 1 mm ST segment depression was first seen was also significantly reduced. Resting cardiac output increased significantly by 0.86 1/min with the patients sitting and by 0.89 1/min standing. The exercise times after food were significantly related to cardiac output even when fasting times were taken into account. Resting heart rate increased significantly by 8.3 beats per minute sitting and 10.4 beats per minute standing. There was little change in blood pressure and no evidence that the double product predicted the post-prandial exercise time. CONCLUSIONS: Worsening of angina was related to the increase in cardiac output after a meal and successful treatment will depend upon the prevention of this increase.

Aged↗
PubMed1990

Effects of enoximone in patients with heart failure uncontrolled by captopril and diuretics.

Ten patients with severe heart failure, symptomatic despite treatment with diuretics and captopril, completed a study of the effect of adding enoximone to their normal treatment. Enoximone or matching placebo was given for 4 weeks in randomized double-blind order following a single-blind placebo run-in period. Exercise capability was measured with two different treadmill protocols, a corridor walk test and by step-counting with body-worn pedometers. Cardiac output and limb blood flow were assessed non-invasively by measuring respiratory gases and by venous occlusion plethysmography. Measurements were made at rest and in response to treadmill exercise. The mean exercise tolerance measured using the modified Bruce treadmill protocol was increased from the placebo value (498 +/- 91 seconds) after both 2 weeks (573 +/- 94 seconds, P = 0.051) and 4 weeks of enoximone (572 +/- 100 seconds, P = 0.057). Enoximone increased exercise duration in fixed workload tests from the placebo value (252 +/- 75 seconds) after 2 weeks' treatment (431 +/- 98 seconds, P = 0.011) and after 4 weeks (381 +/- 85 seconds, (P = 0.01). The percentage improvement with the fixed workload test was greater than with the modified Bruce protocol at week 2 (P = 0.03) and at week 4 (P = 0.051). Enoximone increased the speed of walking 100 m at self-selected slow, normal and fast paces. It had little effect on customary activity of the patients. Enoximone increased cardiac output measured at rest and during submaximal exercise (P = 0.001). It also improved blood flow to the calf muscle at rest and after exercise (P = 0.01). Enoximone has a beneficial effect in chronic heart failure symptomatic despite treatment with diuretics and captopril. The magnitude of its effect, however, depends upon the technique used to assess it.

Aged↗
PubMed1990

Effects of food on the central and peripheral haemodynamic response to upright exercise in normal volunteers.

The central and peripheral haemodynamic effects of a modest meal were investigated in healthy volunteers at rest and in response to submaximal exercise. The meal increased heart rate, cardiac output, oxygen consumption, carbon dioxide production, and minute ventilation at rest and during exercise. The effects of food were additive to those induced by the exercise. Food had no effect on limb blood flow and lowered total systemic vascular resistance suggesting that there were no compensatory changes in regional blood flow to help redirect blood to the gut. An increase in cardiac output, and therefore myocardial work, is the predominant cardiovascular response to eating and this may help explain the postprandial deterioration in symptoms of some patients with cardiovascular disorders.

Adult↗
PubMed1989

Comparison of the effects of captopril and enoximone in patients with severe heart failure: a placebo controlled double-blind study.

The effects of enoximone, a new cyclic adenosine monophosphate phosphodiesterase inhibitor, were compared with those of captopril in a double-blind study in a group of 10 patients with severe heart failure. Four weeks treatment with enoximone improved symptom-limited exercise tolerance from a mean value of 11.33 to 13.36 minutes (P less than 0.05) and 4 weeks of captopril treatment from 11.01 to 13.92 minutes (P less than 0.05). Four of the patients had a greater exercise tolerance taking enoximone, the remaining 6 while taking captopril. Both drugs reduced perceived exertion during submaximal exercise. Minute ventilation measured at rest and during submaximal exercise was also reduced by both drugs. Resting and post exercise calf blood flow was increased to a similar extent with captopril (P less than 0.03) and enoximone (P less than 0.005). There was no difference in calf blood flow and calf vascular resistance between the drugs suggesting that the peripheral haemodynamic effects of enoximone are due to peripheral vasodilatation. Enoximone is a useful drug for the treatment of patients with severe heart failure.

Adult↗
PubMed1989

Changes in peripheral venous tone before the onset of hypertension in women with gestational hypertension.

Forearm venous tone was measured throughout pregnancy in 68 nulliparous women thought to be at high risk of the development of gestational hypertension. Normotensive pregnancy was associated with a progressive venodilatation. Gestational hypertension subsequently developed in 12 women. Before the onset of hypertension, these 12 women showed a greater degree of venodilatation, compared with women who remained normotensive throughout their pregnancies (p less than 0.001). As the hypertension became manifest, the women became relatively venoconstricted (p less than 0.001). Simple, noninvasive measurements of forearm venous tone provide important information about the pathophysiology of gestational hypertension and may be useful in the detection of women who are at increased risk.

Adult↗
PubMed1988

Flosequinan in heart failure: acute haemodynamic and longer term symptomatic effects.

There is no single, simple test with which to evaluate new treatments for heart failure. Various methods need to be used, and a study of both the acute haemodynamic and longer term symptomatic effects of flosequinan, a new direct acting arteriolar and venous vasodilator, was therefore carried out in patients with heart failure. In one group of patients flosequinan increased cardiac output and caused a fall in pulmonary capillary wedge pressure, both effects lasting for 24 hours. In a double blind, placebo controlled study in another group flosequinan improved mean exercise tolerance from 9.9 to 12.7 minutes after four weeks of treatment. The drug also reduced perceived exertion during submaximal exercise and increased calf and therefore skeletal muscle blood flow. It reduced plasma renin activity and noradrenaline concentrations. Flosequinan possesses all the important properties of a drug likely to be of value in the treatment of heart failure.

Aged↗
PubMed1987

The effects of posture on abnormalities of forearm venous tone in women with pregnancy-induced hypertension.

1. Forearm venous tone was measured in the left lateral supine position and in response to passive leg elevation in a group of women with pregnancy-induced hypertension and compared with a group of normotensive pregnant women and a group of non-pregnant women. 2. The women with pregnancy-induced hypertension were venoconstricted in the supine position compared with the normal pregnant women (P less than 0.002). There was no difference in forearm venous tone between the women with pregnancy-induced hypertension and the non-pregnant women. 3. In response to passive leg elevation the women with pregnancy-induced hypertension venodilated (P less than 0.002) whereas there was no change in forearm venous tone in the normotensive pregnant women and the non-pregnant women. There was no change in blood pressure in any of the women after 35 min of leg elevation. 4. These results demonstrate that the abnormal venous vasoconstriction that occurs in women with pregnancy-induced hypertension in the supine position is corrected by passive leg elevation, a manoeuvre which leads to an increase in central blood volume.

Blood Pressure↗
PubMed1986

Symptomatic assessment of patients with heart failure: double-blind comparison of increasing doses of diuretics and captopril in moderate heart failure.

Ten patients with moderate heart failure who still had symptoms despite 40 mg frusemide daily were treated with increased doses of frusemide and the addition of captopril in randomised order. Four different methods were used to assess the patients' response to treatment. Both treatments improved symptom-limited exercise tolerance, higher-dose frusemide having a more favourable effect. Perceived exertion during submaximal exercise was reduced by similar amounts by both treatments. The time taken to walk 100 m at a self-selected slow speed was reduced by both treatments; again higher-dose frusemide had a more beneficial effect. The higher dose of frusemide also had a more favourable effect on visual analogue scores for dyspnoea, fatigue, and general well-being.

Aged↗
PubMed1986

Abnormalities of peripheral venous tone in women with pregnancy-induced hypertension.

Forearm venous tone was measured in two groups of pregnant women: one group with pregnancy-induced hypertension and the other group with normal blood pressure. The women with pregnancy-induced hypertension were venoconstricted in the forearm (P less than 0.01) compared with the pregnant women with normal blood pressure. However, there was no difference in venous tone between the women with pregnancy-induced hypertension and non-pregnant women. There was an inverse correlation between mean arterial blood pressure and forearm venous tone (r = -0.581, P less than 0.001) for all the pregnant women studied. Further evaluation of peripheral venous tone may provide valuable information about the pathophysiology and treatment of women with pregnancy-induced hypertension.

Adult↗
PubMed1986

Abnormalities of the peripheral circulation and respiratory function in patients with severe heart failure.

To investigate the peripheral circulatory and respiratory abnormalities which occur in patients with heart failure, forearm and calf blood flow were measured before and after upright exercise, and respiratory gas exchange was measured during exercise in 26 patients with severe heart failure. Compared with a group of normal subjects the patients had reduced limb blood flow at rest and the response of limb blood flow to upright exercise was also abnormal. The increase in calf blood flow after exercise and the reduction in blood flow in the non-exercising forearm were both smaller in patients than in controls. There was a significant correlation between the maximum exercise duration of the patients and calf blood flow both after exercise and at rest. Compared with another group of control subjects the patients had a higher minute ventilation during exercise and a reduced oxygen consumption. The respiratory exchange ratio during exercise was also higher in patients than in controls. This suggests that there is early onset of anaerobic metabolism during exercise in patients with severe heart failure.

Aged↗
PubMed1985

Effect of aspirin and indomethacin on exercise-induced changes in blood pressure and limb blood flow in normal volunteers.

To evaluate the possible role of prostaglandins in exercise-induced changes in blood pressure and limb blood flow we have compared the effects of aspirin and indomethacin in a double-blind placebo controlled study in a group of normal volunteers. Nine men undertook treadmill exercise after pretreatment with placebo, aspirin and indomethacin. Indomethacin caused a greater increase in systolic blood pressure during exercise than aspirin (p less than 0.05) and a smaller fall in diastolic pressure than either placebo or aspirin (p less than 0.02 and p less than 0.01). Compared with placebo both aspirin and indomethacin attenuated to a similar degree the increase in calf blood flow (p less than 0.05 and p less than 0.03) and the changes in forearm blood flow following exercise. These results suggest that although aspirin and indomethacin both inhibit prostaglandin production they have different effects on exercise-induced changes in blood pressure. They have, however, similar effects on limb blood flow.

Adult↗
PubMed1984

Effects of captopril on abnormalities of the peripheral circulation and respiratory function in patients with severe heart failure.

Limb blood flow and respiratory function were compared in ten patients with severe heart failure inadequately controlled by diuretics and normal control subjects matched for age and sex. Both forearm and calf blood flow, at rest and after exercise, were lower in the patients than in the control subjects. Oxygen consumption during submaximal exercise was also lower in the patients and minute ventilation was higher. Captopril, administered in a single-blind controlled study to the patients, resulted in an improvement in these abnormalities, with the exception of oxygen consumption. It also improved exercise tolerance and reduced perceived exertion during exercise. Captopril is effective treatment for severe heart failure and improves some of the peripheral haemodynamic and respiratory abnormalities.

Acute Disease↗