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PubMed1992

A randomized trial comparing intravenous immune globulin and plasma exchange in Guillain-Barré syndrome. Dutch Guillain-Barré Study Group.

BACKGROUND: The subacute demyelinating polyneuropathy known as Guillain-Barré syndrome improves more rapidly with plasma exchange than with supportive care alone. We conducted a multicenter trial to determine whether intravenous immune globulin is as effective as the more complicated treatment with plasma exchange. METHODS: To enter the study, patients had to have had Guillain-Barré syndrome for less than two weeks and had to be unable to walk independently. They were randomly assigned to receive either five plasma exchanges (each of 200 to 250 ml per kilogram of body weight) or five doses of a preparation of intravenous immune globulin (0.4 g per kilogram per day). The predefined outcome measure was improvement at four weeks by at least one grade on a seven-point scale of motor function. RESULTS: After 150 patients had been treated, strength had improved by one grade or more in 34 percent of those treated with plasma exchange, as compared with 53 percent of those treated with immune globulin (difference, 19 percent; 95 percent confidence interval, 3 percent to 34 percent; P = 0.024). The median time to improvement by one grade was 41 days with plasma exchange and 27 days with immune globulin therapy (P = 0.05). The immune globulin group had significantly fewer complications and less need for artificial ventilation. CONCLUSIONS: In the acute Guillain-Barré syndrome, treatment with intravenous immune globulin is at least as effective as plasma exchange and may be superior.

Follow-Up Studies↗
PubMed1995

[Effect of supplemental oxygen on exercise performance in patients with chronic obstructive pulmonary disease and an arterial oxygen tension over 60 Torr].

The effects of supplemental oxygen on exercise tolerance and exercise-induced dyspnea in patients with chronic obstructive pulmonary disease (COPD) and an arterial oxygen tension (PaO2) over 60 Torr were studied. Twenty two men who met the criteria stated above underwent three 6-minute walk tests while breathing room air, compressed air, or supplemental oxygen, in a double-blind randomized crossover fashion. The distance walked in 6 minutes was recorded, and the degree of dyspnea during exercise was quantified on a visual analog scale with a questionnaire that had eight descriptors of dyspnea sensations. The distances walked were: 535 +/- 27 (SE) for room air, 545 +/- 27 for compressed air, and 563 +/- 23 m for O2. These data indicate a significant placebo effect and an effect of supplemental oxygen. The data regarding dyspnea also indicated both a significant placebo effect and an effect of supplemental oxygen, but the descriptors for the placebo effect differed from those for the effect of supplemental oxygen. Patients in whom arterial desaturation (below 88%) developed during exercise with compressed air benefited from supplemental oxygen: they walked significantly farther and their dyspnea scores for two of the eight descriptors were significantly lower. However, patients in whom arterial desaturation (below 88%) did not develop during exercise with compressed air did not benefit from supplemental oxygen. Nonetheless, the degree of dyspnea during exercise with compressed air could not be used to predict the beneficial effect of supplemental oxygen.

Aged↗
PubMed2003

The metabolic transition speed between backward walking and running.

Although the metabolic transition speed for forward exercise has already been determined, the walk-run transition speed for backward exercise has not been investigated before. The aim of this study was to determine the speed at which it becomes metabolically more efficient to run backwards than to walk backwards. Eighteen healthy volunteers, who successfully completed three backward exercise practice sessions, participated in the study. All subjects randomly performed two exercise tests: backward walking and backward running. Both protocols started at a treadmill speed of 5 km(.)h(-1). Every minute the speed was increased by 0.5 km(.)h(-1) until 8 km(.)h(-1) was reached. Cardiorespiratory variables were continuously measured and blood lactate concentration [La] was determined every 2 min, using the Accusport lactate analyser. At each work load subjects rated their perceived exertion (RPE), using the Borg scale. There were no statistically significant differences in oxygen consumption, minute ventilation and heart rate between 6 and 7 km(.)h(-1), for backward walking and backward running ( P>0.05). There was no statistically significant difference in blood [La] between walking and running at 7.5 km(.)h(-1) ( P>0.05). According to the RPE values, subjects rated running at speeds less than 6 km(.)h(-1) more difficult than walking at similar speeds. We conclude that the metabolic transition speed between backward walking and running is between 6 and 7 km(.)h(-1), which is lower than the metabolic transition speed for forward locomotion (7.2-7.9 km(.)h(-1)).

Adult↗
PubMed2006

[Effectiveness of backward walking treadmill training in lower extremity function after stroke].

OBJECTIVE: To examine the effectiveness of backward walking treadmill training for restoration of motor function, balance and walking speed in patients with stroke. METHODS: Twenty-six patients with stroke, 17 males and 9 females, aged 36 - 64, with the lower extremity Brunnstrom motor recovery stage at 3 or 4, able to walk for 10 m without walking aid or orthosis, were randomly divided into two equal groups: The patients in the control group were to participate in a 60-minutes conventional training five times a week for three weeks, and the patients in the experimental group received 30-minute conventional training and then 30-minute backward walking training five times a week for three weeks. Before the training and 3 weeks after the training, Fugl-Meyer assessment was used to assess the motor function of the lower extremity (FMA-L), Berg balance scale (BBS) was used to assess the balance function, and 10 m maximum walking speed was measured. RESULTS: After the three-week training period, the FMA-L score of the experimental group was 28.0 +/- 3.3, significantly higher than that of the control group (25.5 +/- 2.3, P = 0.033); the BBS score of the experimental group was 51.4 +/- 1.8, significantly higher than that of the control group (47.3 +/- 3.7, P = 0.001, and 10 m MWS of the experimental group was 57 +/- 17, significantly higher than that of the control group (43 +/- 16, P = 0.034). CONCLUSION: A safe and feasible intervention, additional backward walking therapy helps improve the damaged motor function, balance, and walking speed of the patients with stroke.

Exercise Test↗
PubMed1983

Tolerance of early walking with total contact among below-knee amputees--a randomized test.

In order to reduce the need for repeated changes of socket due to postoperative atrophy and resorption of oedema simple temporary limbs are required to delay the casting of individual sockets until the stump is more mature. A randomized study of 95 below-knee amputees was performed with a re-usable temporary one-size prosthesis of endoskeletal type with adjustable tube length. Total contact was obtained by moulding a thin plastic pillow containing small plastic pellets around the stump in parallel connected sections. As air was evacuated the pillow became rigid. The pillow was kept in place about the stump by Velcro bands. Physiotherapists were able to make all adjustments and ambulate the patient 1-2 hours a day. The training started 2-4 weeks after amputation and lasted for 1-4 weeks. Healing problems due to training did not occur in well healed stumps where training started 3 weeks or more after amputation. No negative influence on maturing of stump, hospital stay and walking ability three months after amputation was found.

Aged↗
PubMed2006

No rest for the wounded: early ambulation after hip surgery accelerates recovery.

BACKGROUND: Level 3 evidence-based guidelines recommend first walk after hip fracture surgery within 48 h. Early mobilization is resource and effort intensive and needs rigorous investigation to justify implementation. This study uses a prospective randomized method to investigate the effect of early ambulation (EA) after hip fracture surgery on patient and hospital outcomes. METHODS: Sixty patients (41 women and 19 men; mean age 79.4 years) admitted between March 2004 through December 2004 to The Alfred Hospital, Melbourne, for surgical management of a hip fracture were studied. Randomization was either EA (first walk postoperative day 1 or 2) or delayed ambulation (DA) (first walk postoperative day 3 or 4). Functional levels on day 7 post-surgery, acute hospital length of stay and destination at discharge were compared. RESULTS: At 1 week post-surgery, patients in the EA group walked further than those in the DA group (P = 0.03) and required less assistance to transfer (P = 0.009) and negotiate a step (P = 0.23). Patients in the EA group were more likely to be discharged directly home from the acute care than those in the DA group (26.3 compared with 2.4%) and less likely to need high-level care (36.8 compared with 56%). A failed early ambulation subgroup had significantly more postoperative cardiovascular instability and worse results for all outcome measures. CONCLUSION: EA after hip fracture surgery accelerates functional recovery and is associated with more discharges directly home and less to high-level care.

Aged↗
PubMed1987

The effects of walking on the cross-sectional dimensions of the radius in postmenopausal women.

This report deals with the analysis of data from a 3-year clinical trial on the effect of walking on postmenopausal bone loss. Two hundred fifty-five women, with an average age of 57 at entry, were randomized into two groups, a walking and a control group. Bone measures in the shaft of the radius were carried out with a CT scanner in search of generalized skeletal effects rather than effects localized to the bones of the leg. Although bone density losses were comparable in the two randomized groups, changes in the cross-sectional area of the radius were significantly greater in the walkers with high grip strength (greater than 25 Kg) than in the controls with comparable high grip strength which corresponded to the upper half range of the grip-strength distribution. It is concluded that the moderate activity of walking exerted systemically positive effects on the radius which, within the protocol of the study, could be substantiated only when synergized with inherent muscle strength.

Female↗
PubMed1998

Training effects of short and long bouts of brisk walking in sedentary women.

This study compared the effects of short and long bouts of brisk walking in sedentary women. Forty seven women aged 44.4 +/- 6.2 yr (mean +/- SD) were randomly assigned to either three 10-min walks per day (short bouts), one 30-min walk per day (long bouts) or no training (control). Brisk walking was done on 5 d x wk(-1), at 70 to 80% of maximal heart rate, typically at speeds between 1.6 and 1.8 m x s(-1) (3.5 and 4.0 mph), for 10 wk. Subjects agreed not to make changes to their diet. Twelve short-bout walkers, 12 long-bout walkers, and 10 controls completed the study. Relative to controls, VO2max (short-bout, +2.3 +/- 0.1 mL x kg(-1) x min(-1); long-bout, +2.4 +/- 0.1 mL x kg(-1) x min(-1); controls, -0.5 +/- 0.1 mL x kg(-1) x min[-1]) and the VO2 at a blood lactate concentration of 2 mmol x L(-1) increased in walkers (both P < 0.05), with no difference in response between walking groups. Neither heart rate during standard, submaximal exercise nor resting systolic blood pressure changed in a different way in walkers and controls. The sum of four skinfold thicknesses decreased in both walking groups (P < 0.05) but body mass (short-bout, -1.7 +/- 1.7 kg; long-bout, -0.9 +/- 2.0 kg; controls, +0.6 +/- 0.7 kg) and waist circumference decreased significantly only in short-bout walkers. Changes in anthropometric variables did not differ between short- and long-bout walkers. Thus short bouts of brisk walking resulted in similar improvements in fitness and were at least as effective in decreasing body fatness as long bouts of the same total duration.

Adult↗
PubMed2002

Questionnaire survey of users of NHS walk-in centres: observational study.

BACKGROUND: NHS walk-in centres have recently been established throughout England to improve access to primary health care. AIM: To determine the characteristics and experiences of people consulting NHS walk-in centres compared with general practice. DESIGN OF STUDY: Observational study using questionnaires. SETTING: Thirty-eight walk-in centres and 34 neighbouring general practices. METHOD: People attending randomly selected survey sessions at walk-in centres or neighbouring general practices on a 'same-day' basis were given a self-administered questionnaire. This collected data about socio-demographic characteristics, reasons for consulting, attitudes to continuity, satisfaction, enablement, referrals, and intentions. RESULTS: Walk-in centre visitors were more likely to be owner-occupiers (55% versus 49%; P<0.001), to have further education (25% versus 19%; P = 0.006), and to be white (88% versus 84%; P< 0.001) than general practice visitors. Main reasons for attending a walk-in centre were speed of access and convenience. Walk-in centre visitors were more likely to attend on the first day of illness (28% versus 10%; P<0.001), less likely to expect a prescription (38% versus 70%, P<0.001), and placed less importance on continuity of care (adjusted odds ratio = 0.58; 95% CI = 0.50 to 0.68) than general practice visitors. People were more satisfied with walk-in centres (adjusted mean difference = 6.6%; 95% CI = 5.0% to 8.2%). Enablement scores were slightly higher in general practice (adjusted mean difference = 0.40; 95 % CI = 0.11 to 0. 6). Following the consultation 13% of walk-in centre visitors were referred to general practice, but 32% intended to make an appointment. CONCLUSION: NHS walk-in centres improve access to care, but not necessarily for those people with greatest health needs. People predominantly attend with problems of recent onset as an alternative to existing health providers, and are very satisfied with the care received. These benefits need to be considered in relation to the cost, and in comparison with other ways of improving access to health care.

Adolescent↗
PubMed1993

Cardiorespiratory responses to exercise training in septuagenarian women.

Cardiorespiratory responses to a 12wk moderate exercise training program were examined in 30 sedentary elderly women (mean age = 73.6 +/- 0.7 yr). In addition, 12 highly conditioned (HC) older women (mean age = 72.5 +/- 1.8 yr; 11.2 +/- 1.2 yr training; 1.6 +/- 0.2 hr.d-1 aerobic activity) were tested at baseline for cross-sectional comparisons. The VO2max and VEmax of the HC subjects were 67% and 36% higher, respectively, (p < 0.001) than the combined sedentary subjects at baseline. Sedentary subjects were randomly assigned to a walking (WALK) or calisthenics control (CAL) group. The WALK group exercised 5 d.wk-1 for 30-40 min per session at 60.0 +/- 1.9% heart rate reserve while the CAL group engaged in mild musculoskeletal exercise. The WALK group demonstrated significant improvement in VO2max compared to CAL subjects at 12 wk (12.6% vs 2.2%, F = 5.74, p = 0.005). These data show that septuagenarian women demonstrate significant improvement in maximal cardiorespiratory fitness through moderate exercise training.

Aged↗
PubMed1987

[Walk training and drug therapy in peripheral arterial occlusive disease. A randomized, prospective, placebo-controlled double-blind study].

It was demonstrated in a prospective, randomized and placebo-controlled double-blind study of two groups of 15 patients each with peripheral arterial occlusive disease in stage IIb of Fontaine that the combination of intravenous and oral administration of Pentoxifylline with walk training was superior to walk training alone. Comparison of the two groups revealed a significant increase in pain-free walking capacity, as well as reduction in plasma viscosity and platelet aggregation in the patients of the combination group. A significant reduction in platelet aggregation and rigidity occurred with time in this group only, while there was no significant difference between the groups with regard to these two parameters at the end of the treatment period.

Administration, Oral↗
PubMed2002

Ankle-foot orthosis has limited effect on walking test parameters among patients with peripheral ankle dorsiflexor paresis.

The aim of this study was to determine the relationship between ankle dorsiflexor strength and performances on several walking tests and to determine the effect of ankle-foot orthosis (AFO) use on walking tests. The following tests were used: 10-metre walking test (with and without three stairs), a complex walking task (6-minute walk with cognitive loading) and a subjective evaluation (SIP68 mobility scale and questionnaire). Isometric strength of the ankle dorsiflexors was measured. All walking tests were performed with and without AFO in random order. When relating torque values to walking performances, the highest correlation was found with the "10 metre" and "10 metre with stairs" test (r = -0.51, i.e. an inverse relationship). No threshold in the degree of paresis was found below which walking disability suddenly increased. No significant improvement could be demonstrated from AFO use on the 10-metre tests. Improvement on the 6-minute test was nearly significant (p = 0.06), the questionnaire revealed a positive opinion on AFO use related to overall walking function and effort. Thus, we have to conclude that these walking tests do not aid the clinician in estimating the severity of (progression of) the paresis nor to detect differences in degree of paresis between subjects.

Adult↗
PubMed2006

Reliability, validity, and responsiveness of a 2-min walk test to assess exercise capacity of COPD patients.

PURPOSES: To investigate the reliability, validity, and responsiveness of a 2-min walk test (2MWT) in Chinese COPD patients with moderate-to-severe disease. METHODS: This study consisted of two parts. Forty-seven stable COPD patients with moderate-to-severe disease participated in the first part of study for the investigation of reliability and validity. The demographic and anthropomorphic data collected included age, gender, body weight, height, and body mass index. Each subject performed a pulmonary function test, a cardiopulmonary exercise test, three trials of a 2MWT, and two trials of 6-min-walk test (6MWT) in random order within a 5-day period. Fifteen of these subjects participated in the second part of study for the evaluation of the responsiveness of the 2MWT following pulmonary rehabilitation. The 2MWT and 6MWT were conducted before and after the program for comparison. RESULTS: Forty-five subjects (mean [+/- SD] age, 71.8 +/- 8.3 years; mean FEV1, 0.88 +/- 0.27 L) completed the first part of study, and 9 subjects (mean age, 74 +/- 8.7 years; mean FEV1, 0.94 +/- 0.28 L) completed the second part of study. The intraclass correlation coefficient of the repeated 2MWTs was high (R = 0.9994; p < 0.05), mean differences across trials ranged from 0.3 to 0.8 m (95% confidence interval, -3.1 to 4.6 m) demonstrated its high test-retest reliability. Significant correlations were found between the 2MWT and the 6MWT, the maximum oxygen uptake (V(O2)max) in milliliters per minute, and the V(O2)max in milliliters per kilogram per minute (r = 0.937, 0.454, and 0.555 respectively; p < 0.0125). Following rehabilitation, there were significant improvements in the mean 2MWT and 6MWT walking distance of 17.2 +/- 13.8 m and 60.6 +/- 35.5 m, respectively, with moderate effect sizes (0.61 and 0.53, respectively) and large standardized mean responses (1.25 and 1.70, respectively). High correlation was found between changes in the 2MWT and the 6MWT (r = 0.70; p < 0.05). CONCLUSION: The 2MWT was shown to be a reliable and valid test for the assessment of exercise capacity and responsive following rehabilitation in patients with moderate-to-severe COPD. It is practical, simple, and well-tolerated by patients with severe COPD symptoms.

Aged↗
PubMed2004

High intensity aerobic interval exercise is superior to moderate intensity exercise for increasing aerobic capacity in patients with coronary artery disease.

BACKGROUND: Increased aerobic exercise capacity appears to reduce both all-cause mortality and cardiovascular disease mortality. Physical exercise to improve peak oxygen uptake (VO2peak) is thus strongly recommended, however evidence regarding the most efficient training intensity for patients with coronary artery disease (CAD) is still lacking. The purpose of this randomized study was therefore to assess the effects of high intensity aerobic interval exercise compared to moderate intensity exercise, representing the same total training load, for increasing VO2peak in stable CAD-patients. METHODS: Twenty-one stable CAD-patients were randomized to supervised treadmill walking at either high intensity (80-90% of VO2peak) or moderate intensity (50-60% of VO2peak) three times a week for 10 weeks. RESULTS: After training VO2peak increased by 17.9% (P=0.012) in the high intensity group and 7.9% (P=0.038) in the moderate intensity group. The training-induced adaptation was significantly higher in the high intensity group (P=0.011). CONCLUSIONS: High intensity aerobic interval exercise is superior to moderate exercise for increasing VO2peak in stable CAD-patients. As VO2peak seems to reflect a continuum between health and cardiovascular disease and death, the present data may be useful in designing effective training programmes for improved health in the future.

Coronary Artery Disease↗
PubMed2002

Body temperature in sedentary adults during moderate exercise: no effect from exercise the day before.

BACKGROUND: Epidemiological findings show a continued presence of exertional heat injury during military basic recruit training. Current guidelines do not consider the carry-over effects of prior exercise or exposure to high ambient temperatures on the risk of succumbing to heat illness. HYPOTHESIS: From the epidemiological evidence we hypothesized that both prior exercise and exposure to hot environments on the day before would increase the core temperature response during exercise the next day. METHODS: Seven sedentary and non heat-acclimated men and women each performed eight randomized exposures involving treadmill walking for a maximum of 2 h every 2 wk. Two separate control trials at a wet bulb globe temperature (WBGT) of 22.5 degrees C and 26.5 degrees C consisted of exercise during the morning only. Six experimental trials involved successive days of exercise with trials on the second day at either a WBGT of 22.5 degrees C or 26.5 degrees C. All of the experimental trials involved walking during the first morning at a WBGT of 22.5 degrees C. Further, four of these trials included additional exercise in the afternoon at either a WBGT of 22.5 degrees C (two trials) or 29.5 degrees C (two trials). RESULTS: There was no impact of prior exercise on the day preceding the tests at either WBGT for any of the dependent measures. Rectal temperatures increased to 38.0 degrees C at the WBGT of 22.5 degrees C and to 38.5 degrees C for trials at 26.5 degrees C. There were also no carry-over effects from exercise conducted during the preceding afternoon. CONCLUSIONS: Under situations where individuals are well hydrated, rested, and free of injury, illness, and drug use, repeated exercise bouts on successive days do not alter the thermoregulatory response to exercise.

Adult↗
PubMed2003

Obstacle avoidance during human walking: H-reflex modulation during motor learning.

The goal of this study was to investigate changes of H-reflex amplitudes during a motor learning task. Subjects with reduced vision were instructed to step over an obstacle on a treadmill as low as possible, while the soleus H-reflex was elicited. Acoustic warning and feedback signals about performance were provided. Performance improvement was associated with a decrease of muscle activity, needed to step over the obstacle (rectus femoris, biceps femoris, tibialis anterior and gastrocnemius medialis muscles), and of foot clearance, while joint angle trajectories from knee and ankle became more stable. The experiment consisted of five runs, three with normal treadmill walking and two with randomly stepping over the obstacle (100 times). H-reflexes were elicited at early and late stance phase before stepping over the obstacle. H/M ratio, latency and duration were determined. The values of these measures were calculated for the onset and end of a run and their course over time was evaluated using a correlation coefficient. The largest adaptations with a significant increase of reflex amplitude occurred during the first obstacle run. This increase lasted only briefly and the reflex amplitudes decreased to their previous values. During the later obstacle run, no H-reflex modulation occurred. It is concluded that a motor learning task causes adaptational effects not only on performance, but also on H-reflex responses. The results indicate that most of the modulation of H-reflexes is probably due to supraspinal influences on reflex transmission. The observations made are probably less specific for this motor task (stepping over the obstacle), but rather associated with the increased attention required by the motor learning task during the first obstacle run.

Adult↗
PubMed2003

Effects of the oral endothelin-receptor antagonist bosentan on echocardiographic and doppler measures in patients with pulmonary arterial hypertension.

OBJECTIVES: The purpose of this study was to investigate the effects of bosentan (125 or 250 mg twice daily) on echocardiographic and Doppler variables in 85 patients with World Health Organization class III or IV pulmonary arterial hypertension (PAH). BACKGROUND: Bosentan, an orally active dual endothelin-receptor antagonist, improves symptoms, exercise capacity, and hemodynamics in patients with PAH. METHODS: Patients had primary pulmonary hypertension (84%) or PAH associated with connective tissue disease. Of these, 29 patients received placebo and 56 received bosentan (1:2 randomization). Six-minute walk tests and echocardiograms were performed at baseline and after 16 weeks of treatment. RESULTS: Baseline characteristics were similar in the placebo and bosentan groups, and echocardiographic and Doppler findings were consistent with marked abnormalities of right ventricular (RV) and left ventricular (LV) structure and function that were due to PAH. The treatment effect on 6-min walking distance was 37 m in favor of bosentan (p = 0.036). Treatment effects of bosentan compared with placebo on other parameters were as follows: Doppler-derived cardiac index = +0.4 l/min/m(2) (p = 0.007), LV early diastolic filling velocity = +10.5 cm/s (p = 0.003), LV end-diastolic area = +4.2 cm(2) (p = 0.003), LV systolic eccentricity index = -0.12 (p = 0.047), RV end-systolic area = -2.3 cm(2) (p = 0.057), RV:LV diastolic areas ratio = -0.64 (p = 0.007), Doppler RV index = -0.06 (p = 0.03), and percentage of patients with an improvement in pericardial effusion score = 17% (p = 0.05). CONCLUSIONS: Bosentan improves RV systolic function and LV early diastolic filling and leads to a decrease in RV dilation and an increase in LV size in patients with PAH.

Administration, Oral↗
PubMed2000

Importance of ventricular rate after mode switching during low intensity exercise as assessed by clinical symptoms and ventilatory gas exchange.

Automatic mode switching from DDD(R) to DDI(R) or VVI(R) pacing modes has improved dual chamber pacing in patients at high risk for supraventricular tachyarrhythmias. However, little is known about the effect of ventricular pacing rate adaptation after mode switching. We conducted a single-blinded, crossover study in 15 patients (58 +/- 21 years) with a DDD pacemaker who had AV block and normal sinus node function to investigate the influence of pacing rate adaptation to intrinsic heart rate during low intensity exercise. Patients performed two tests (A/B) of low intensity treadmill exercise (0.5 W/kg) in randomized order. They initially walked for 6 minutes while paced in DDD mode. The pacing mode was then switched to VVI with a pacing rate of either 70 beats/min (test A) or matched to the intrinsic heart rate (95 +/- 11 beats/min test B). Respiratory gas exchange variables were determined and patients classified the effort before and after mode switching on a Borg scale from 6 to 20. Percentage changes of respiratory gas exchange measurements were significantly larger (O2 consumption: -8.2 +/- 5.0% vs. -0.6 +/- 7.2%; ventilatory equivalent of CO2 exhalation: 5.3 +/- 4.9% vs. 1.5 +/- 4.3%; respiratory exchange ratio: 7.0 +/- 2.2% vs. 3.5 +/- 3.0%; end-tidal CO2: -5.7 +/- 2.9% vs. -1.8 +/- 2.7%; all P < 0.01) and the increase in subjective assessment of the effort tended to be higher (mean increase on Borg scale: 1.6 +/- 1.9 vs. 1.1 +/- 1.8, P = 0.07) after heart rate unadjusted than after adjusted mode switching. Mode switching from DDD to VVI pacing is better tolerated and gas exchange measurements are less influenced if ventricular pacing rate is adjusted to the level of physical activity. Thus, pacing rate adjustment should be considered as part of automatic mode switch algorithms.

Adolescent↗