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PubMed1999

Vascular surgical society of great britain and ireland: prospective randomized double-blind placebo-controlled crossover study to assess the effect of sublingual glyceryl trinitrate in patients with intermittent claudication

BACKGROUND: The effect of sublingual glyceryl trinitrate (GTN) on the claudication distance (CD) and maximum walking distance (MWD) of patients with intermittent claudication was assessed. METHODS: Inclusion criteria were: history of intermittent claudication; resting ankle : brachial pressure index (ABPI) of 1.00 or less; fall in ABPI of more than 0.1 following exercise; and patient not taking nitrates. In the first study 22 patients (median age 69 (range 60-73) years, 16 men, five diabetic, median resting ABPI 0.57 (range 0.1-0.64)) had their CD and MWD measured on a treadmill set at 3.2 km h-1 and 10 per cent gradient. They were then randomized to either GTN or placebo spray, and the distances were remeasured. The crossover portion of the study was then completed. In the second study 28 patients (median age 68 (range 45-84) years, 20 men, six diabetic, median resting ABPI 0.57 (range 0.13-0.98)) were randomized to either GTN or placebo and walked at their own pace along a flat corridor for 15 min. Following a rest of 15 min, the crossover portion of the study was completed. Statistical analysis was by the Wilcoxon matched pairs signed rank test. RESULTS: CONCLUSION: GTN can increase the MWD by 19 per cent when patients with intermittent claudication are walked on a treadmill and by 9 per cent when walking at their own pace on a flat gradient.

Journal Article↗
PubMed1997

Effects of exercise on fatigue, physical functioning, and emotional distress during radiation therapy for breast cancer.

PURPOSES/OBJECTIVES: To test the hypothesis that women participating in a walking exercise program during radiation therapy treatment for breast cancer would demonstrate more adaptive responses as evidenced by higher levels of physical functioning and lower levels of symptom intensity than women who did not participate. DESIGN: Experimental, two-group pretest, post-test. SETTING: Two university teaching hospital outpatient radiation therapy departments. SAMPLE: 46 women beginning a six-week program of radiation therapy for early stage breast cancer. METHODS: Following random assignment, subjects in the exercise group maintained an individualized, self-paced, home-based walking exercise program throughout treatment. The control group received usual care. Dependent variables were measured prior to and at the end of radiation therapy. In addition, symptoms were assessed at the end of three weeks of treatment. MAIN RESEARCH VARIABLES: Participation in the walking exercise program, physical functioning fatigue, emotional distress, and difficulty sleeping. FINDINGS: Hypothesis testing by multivariate analysis of covariance, with pretest scores as covariates, indicated significant differences between groups on outcome measures (p < 0.001). The exercise group scored significantly higher than the usual care group on physical functioning (p = 0.003) and symptom intensity, particularly fatigue, anxiety, and difficulty sleeping. Fatigue was the most frequent and intense subjective symptom reported. CONCLUSIONS: A self-paced, home-based walking exercise program can help manage symptoms and improve physical functioning during radiation therapy. IMPLICATIONS FOR NURSING PRACTICE: Nurse-prescribed and -monitored exercise is an effective, convenient, and low-cost self-care activity that reduces symptoms and facilitates adaptation to breast cancer diagnosis and treatment.

Adult↗
PubMed1996

The modified Gait Abnormality Rating Scale for recognizing the risk of recurrent falls in community-dwelling elderly adults.

BACKGROUND AND PURPOSE: The purpose of this study was to determine the reliability and validity of measurements obtained with a seven-item modified version of the Gait Abnormality Rating Scale (GARS-M), an assessment of gait designed to predict risk of falling among community-dwelling, frail older persons. SUBJECTS: Fifty-two community-dwelling, frail older persons, with a mean age of 74.8 years (SD = 6.75), participated. METHODS: A history of falls was determined from self-report or by proxy report. The GARS-M was scored from videotapes of subjects walking at self-selected paces. Gait characteristics were recorded during a timed walk on a 6-m brown-paper walkway. RESULTS: Scores obtained by three raters for 23 subjects demonstrated moderate to substantial intrarater and interrater reliability. Concurrent validity, as assessed by Spearman rank-order correlation coefficients, was demonstrated for the relationship between GARS-M scores and stride length (r = -.754) and for the relationship between GARS-M scores and walking speed (r = -.679). Mean GARS-M scores distinguished between frail older persons with and without a history of recurrent falls (mean GARS-M scores of 9.0 and 3.8, respectively). CONCLUSION AND DISCUSSION: The GARS-M is a reliable and valid measure for documenting gait features associated with an increased risk of falling among community-dwelling, frail older persons and may provide a clinically useful alternative to established quantitative gait-assessment methods.

Accidental Falls↗
PubMedDate not supplied

Relationships between respiratory symptoms and FEV1 in men and women with normal lung function: The Korean Health and Genome Study.

Although the prevalence of chronic obstructive pulmonary disease (COPD) and its relationship with respiratory symptoms are well documented, few studies have focused on individuals with normal lung function, particularly in developed regions of Asia. The purpose of this report is to examine the relationship between respiratory symptoms and FEV1 in a population-based sample of Korean men and women with normal lung function. Subjects comprised 7518 individuals aged 40-69 years without airflow obstruction based on spirometric testing and in the absence of a medical history of pulmonary disease. Respiratory symptoms included chronic cough, chronic phlegm, wheezing, and shortness of breath. In men, the age-adjusted mean FEV1 was lower by 165 ml in smokers and 133 ml in nonsmokers in the presence versus the absence of wheezing (p < 0.05). While walking at a usual pace, FEV1 in smoking men was 210 ml lower in the presence versus the absence of shortness of breath (p < 0.05). Among nonsmoking men, overall shortness of breath and shortness of breath while walking uphill were associated with a lower FEV1 by 56 and 80 ml, respectively) versus those who reported having no shortness of breath (p < 0.05). Respiratory symptoms were unrelated to FEV1 in women smokers, although only 3.5% smoked cigarettes. In nonsmoking women, FEV1 was lower by an average of 89 ml in the presence versus the absence of wheezing (p < 0.001). Nonsmoking women also had a lower FEV1 in the presence of shortness of breath (overall, while at rest, and while walking uphill or at a usual pace, p < 0.001). Our findings suggest that respiratory symptoms are associated with a lower FEV1 in men and nonsmoking women with normal lung function. Whether respiratory symptoms can be used to identify individuals at risk for developing COPD needs further study.

Adult↗
PubMed1993

Why cats pace on the treadmill.

There have been many studies suggesting that locomotion on a treadmill tends to be different than locomotion at similar velocities overground, but no satisfactory mechanical or neural mechanisms to account for the differences have been identified. The most prominent difference is the tendency to adopt a pacing gait for both walking and trotting speeds, in which the legs on one side of the body move in phase as lateral couplets rather than the typical diagonal couplet pattern seen overground. Using conventional video analysis, we quantified the gait patterns of intact, adult cats walking at various speeds overground and in a motorized treadmill. We noted that cats paced most frequently when they were at the front end of the treadmill enclosure, and that this gait was associated with an extended stride length that permitted the animals to maintain a higher duty factor of support (mean number of feet on the ground). We propose that the animal extends its stride specifically to improve the duty factor in anticipation of sudden stops of the treadmill belt and that it converts abruptly from diagonal to lateral gait because the extended stride results in collisions between ipsilateral hind and front feet.

Acceleration↗
PubMed2001

A comparison of the shuttle and 6 minute walking tests with measured peak oxygen consumption in patients with heart failure.

This study investigated the use of an incremental, externally-paced 10 m shuttle walk test (SWT) as an objective, reliable and predictive test of functional capacity in patients with heart failure (CHF). The SWT was compared to a 6 minute walk test (6WT) and a maximal symptom-limited treadmill peak oxygen consumption (VO2peak) test. Experiment 1 examined the reproducibility of the SWT. Two SWF trials were performed and distance ambulated (DA), heart rate (HR) and rate of perceived exertion (RPE) results compared. In experiment 2, SWT, 6WT, and VO2 peak tests were performed and HR. RPE and ambulatory VO2 compared. The SWT demonstrated strong test/retest reliability for DA (r = 0.98). HR (r = 0.96) and RPE (r = 0.89). Treadmill VO2 peak was significantly correlated with DA during the SWT (r = 0.83, P < 0.05), but not the 6WT. SWT peak VO2 (18.5 +/- 1.8 ml.kg(-1) x min(-1)) and treadmill VO2 peak (18.3 +/-2.0 ml.kg(-1) x min(-1)) were also highly correlated (r = 0.78, P < 0.05). Conversely, 6WT peak VO2 and treadmill VO2 peak were not significantly correlated. This study suggests the SWT is a reliable, objective test, highly predictive of VO2 peak which may be a more optimal field exercise test than the self paced 6WT.

Exercise Test↗
PubMed2004

Physical activity, including walking, and cognitive function in older women.

CONTEXT: Physical activity may help maintain cognitive function in older adults. OBJECTIVE: To examine the relation of long-term regular physical activity, including walking, to cognitive function. DESIGN: Women reported participation in leisure-time physical activities on biennial mailed questionnaires beginning in 1986. We assessed long-term activity by averaging energy expenditures from questionnaires in 1986 through participants' baseline cognitive assessments (1995 to 2001). We used linear regression to estimate adjusted mean differences in baseline cognitive performance and cognitive decline over 2 years, across levels of physical activity and walking. SETTING AND PARTICIPANTS: Nurses' Health Study, including 18 766 US women aged 70 to 81 years. MAIN OUTCOME MEASURE: Validated telephone assessments of cognition administered twice approximately 2 years apart (1995 to 2001 and 1997 to 2003), including tests of general cognition, verbal memory, category fluency, and attention. RESULTS: Higher levels of activity were associated with better cognitive performance. On a global score combining results of all 6 tests, women in the second through fifth quintiles of energy expenditure scored an average of 0.06, 0.06, 0.09, and 0.10 standard units higher than women in the lowest quintile (P for trend <.001). Compared with women in the lowest physical activity quintile, we found a 20% lower risk of cognitive impairment for women in the highest quintile of activity. Among women performing the equivalent of walking at an easy pace for at least 1.5 h/wk, mean global scores were 0.06 to 0.07 units higher compared with walking less than 40 min/wk (P< or =.003). We also observed less cognitive decline among women who were more active, especially those in the 2 highest quintiles of energy expenditure. Women in the fourth and fifth quintiles had mean changes in global scores that were 0.04 (95% confidence interval, 0.02-0.10) and 0.06 (95% confidence interval, 0.02-0.11) standard units better than those in the lowest quintile. CONCLUSION: Long-term regular physical activity, including walking, is associated with significantly better cognitive function and less cognitive decline in older women.

Aged↗
PubMed2005

GPS analysis of human locomotion: further evidence for long-range correlations in stride-to-stride fluctuations of gait parameters.

During free walking, gait is automatically adjusted to provide optimal mechanical output and minimal energy expenditure; gait parameters, such as cadence, fluctuate from one stride to the next around average values. It was described that this fluctuation exhibited long-range correlations and fractal-like patterns. In addition, it was suggested that these long-range correlations disappeared if the participant followed the beep of metronome to regulate his or her pace. Until now, these fractal fluctuations were only observed for stride interval, because no technique existed to adequately analyze an extended time of free walking. The aim of the present study was to measure walking speed (WS), step frequency (SF) and step length (SL) with high accuracy (<1 cm) satellite positioning method (global positioning system or GPS) in order to detect long-range correlations in the stride-to-stride fluctuations. Eight participants walked 30 min under free and constrained (metronome) conditions. Under free walking conditions, DFA (detrended fluctuation analysis) and surrogate data tests showed that the fluctuation of WS, SL and SF exhibited a fractal pattern (i.e., scaling exponent alpha: 0.5 < alpha < 1) in a large majority of participants (7/8). Under constrained conditions (metronome), SF fluctuations became significantly anti-correlated (alpha < 0.5) in all participants. However, the scaling exponent of SL and WS was not modified. We conclude that, when the walking pace is controlled by an auditory signal, the feedback loop between the planned movement (at supraspinal level) and the sensory inputs induces a continual shifting of SF around the mean (persistent anti-correlation), but with no effect on the fluctuation dynamics of the other parameters (SL, WS).

Adult↗
PubMed1992

Ventricular rate-adaptive pacing in the elderly.

The role of ventricular rate-adaptive pacing (VVIR) in the elderly was investigated in 12 patients with a mean age of 85 +/- 2 years (range 75-95 years) with implanted activity-initiated VVIR pacemakers. Although four patients had significant extracardiac diseases, all were capable of independent walking and self care. The pacing rate achieved during structured daily activities (walking, climbing stairs, washing, bed-making and scrubbing floors) were compared with those achieved by 10 age-matched healthy subjects. Apart from the more strenuous activities (ascending stairs and floor-scrubbing), the pacing rates achieved by the patients were comparable to those of the healthy subjects and occurred within an appropriate time. In a 4-weekly randomized, double-blind crossover protocol in the VVI and VVIR pacing modes, all patients underwent assessments in a 12-min walking distance test, a 24 h non-invasive ambulatory blood pressure recording and a symptomatic documentation. During VVIR pacing, the 12-min walking distance was significantly improved compared to VVI pacing (556 +/- 52 vs. 545 +/- 55 m, P less than 0.05). There was no difference between the recorded blood pressure and symptom scores between the two pacing modes, although most patients preferred VVIR pacing (P less than 0.05). It is concluded that VVIR pacing in this elderly population can improve exercise capacity, and the patients' preference for the VVIR mode was documented despite the absence of a measurable difference in symptomatology.

Aged↗
PubMed2000

Association of lifestyle with serum lipid levels: a study of middle-aged Japanese men.

Cross-sectional associations between lifestyle and serum lipid levels were examined in 1591 Japanese male office workers aged 35 to 59 years in Osaka, Japan. From multiple linear regression analyses, significant correlates with low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and Log triglyceride levels and the ratio of LDL cholesterol to HDL cholesterol were, in the order of relative importance: BMI, alcohol intake (negative) and age for LDL cholesterol level; BMI (negative), cigarette smoking (negative), alcohol intake, consideration for nutritional balance, hours of brisk walking, hours of walking at an ordinary pace and physical exercise for HDL cholesterol level; BMI, cigarette smoking, consideration for nutritional balance (negative), hours of work (negative), alcohol intake and coffee drinking (negative) for Log triglyceride level; and BMI, alcohol intake (negative), cigarette smoking, consideration for nutritional balance (negative), age, hours of brisk walking (negative) and the frequency of snack intake between meals for the ratio of LDL cholesterol to HDL cholesterol. Our data suggest that obesity, cigarette smoking and snack intake between meals are atherogenic whereas alcohol consumption, consideration for nutritional balance and walking long hours, especially at a brisk pace, are anti-atherogenic in middle-aged Japanese men.

Adult↗
PubMed1988

Muscle strength in the triceps surae and objectively measured customary walking activity in men and women over 65 years of age.

1. Objective measurements of the maximal voluntary strength of triceps surae and the amount and speed of customary walking have been made in 56 men and 66 women aged over 65 years, who were living independently. 2. Strength was measured using a dynamometer based upon a hydraulic system (Bourdon tube). Walking was assessed, for amount using a mechanical accelerometer (pedometer) over a week, and for speed using a self-paced test for normal walking over 100 m on the level. The reliability and validity of these methods has been described. 3. The men were significantly stronger (1128 +/- 206 vs 873 +/- 177 N) even after adjustment for body weight; their amount of walking was similar to that of women, but they walked significantly faster (4.8 +/- 0.6 vs 4.2 +/- 0.6 km/h). Men were significantly more active in leisure pursuits (as assessed by questionnaire). 4. Significant associations between strength and chosen normal walking speed were found for both sexes (r = 0.41, P less than 0.001 for men and r = 0.36, P less than 0.01 for women). The amount of walking (daily stepscore as a mean from 7 consecutive days recorded) was significantly but less strongly correlated with strength (r = 0.30, P less than 0.05) in the men only. 5. Multiple regression analysis showed that in men neither age nor amount of walking had any further effect in addition to speed, but in women age had an additional effect (multiple R = 0.48). 6. An association has been demonstrated which raises the possibility of reversing loss of muscle strength through increased daily activity.

Aged↗
PubMed2004

A task-orientated intervention enhances walking distance and speed in the first year post stroke: a randomized controlled trial.

OBJECTIVE: To evaluate the efficacy of a task-orientated intervention in enhancing competence in walking in people with stroke. DESIGN: Two-centre observer-blinded stratified block-randomized controlled trial. SETTING: General community. SUBJECTS: Between May 2000 and February 2003, 91 individuals with a residual walking deficit within one year of a first or recurrent stroke consented to participate. INTERVENTIONS: The experimental intervention comprised 10 functional tasks designed to strengthen the lower extremities and enhance walking balance, speed and distance. The control intervention involved the practice of upper extremity activities. Subjects in both groups attended sessions three times a week for six weeks. MAIN MEASURES: Six-minute walk test (SMWT), 5-m walk (comfortable and maximum pace), Berg Balance Scale, timed 'up and go'. RESULTS: At baseline, subjects in the experimental (n = 44) and control (n = 47) groups walked an average distance of 209 m (SD = 126) and 204 m (SD =131), respectively, on the SMWT. Mean improvements of 40 m (SD =72), and 5 m (SD =66) were observed following the experimental and control interventions, respectively. The between-group difference was 35 m (95% confidence interval (CI) 7, 64). Significant between-group effects of 0.21 m/s (95% CI 0.12, 0.30) and of 0.11 m/s (95% CI 0.03, 0.19) in maximum and comfortable walking speed, respectively, were observed. People with a mild, moderate or severe walking deficit at baseline improved an average of 36 (SD =96), 55 (SD = 56) and 18 m (SD = 23), respectively, in SMWT performance following the experimental intervention. CONCLUSIONS: Study findings support the efficacy of a task-orientated intervention in enhancing walking distance and speed in the first year post stroke, particularly in people with moderate walking deficits.

Adult↗
PubMed1995

An approach in the assessment of pacing hemodynamics: a comparison of VVI and DDD.

Previous methods for assessment of pacemaker hemodynamics have been limited to a rigid hospital environment. An alternative is the ambulatory ventricular function monitor (C-VEST) that, with a single injection of technetium-99m, permits the continuous measurement of relative ejection fraction (EF) and cardiac output (CO) during the activities of daily living. A study of reproducibility and a comparison of dual chamber (DDD) and fixed rate ventricular (VVI) pacing are presented. Reproducibility was assessed in six patients (4 males; mean age 58, range 27-78 years) with a mean EF of 48.5% (range 34%-62%) and DDD pacemakers, implanted for conduction abnormalities. In addition, 11 patients (7 males; mean age 55.5, range 34-75 years) with a mean EF of 48.5% (range 34%-65%), chronic complete heart block, and DDD pacemakers were used for the comparative study. After an initial multigated scan, the monitor was positioned over the left ventricle and kept in place with the plastic C-VEST. The patients undergoing the reproducibility study performed three shuttle walking tests with 20 minutes of rest in between. The patients in the comparative study were randomized to either VVI or DDD mode and performed one shuttle walking test in each pacing mode. The results confirmed that the C-VEST produces reproducible results with no significant difference in peak CO between the three shuttle walks. In addition, it confirmed previous hemodynamic studies showing that DDD pacing was superior to VVI pacing both at rest (P < 0.004) and at exercise (P < 0.002). These findings show the C-VEST to be an extremely useful tool for the hemodynamic assessment of pacemaker patients.

Adult↗
PubMed2002

Comparison of hip and knee muscle moments in subjects with and without knee pain.

Elderly subjects with and without knee pain walked at a comfortable pace during gait analysis. Comparison of peak hip and knee internal extensor generalized muscle moments (GMMs) during loading response was made between groups. Walking velocity, peak hip internal extensor GMM, and knee range of motion (ROM) were significantly less for the group with knee pain than for the group without pain. Peak hip internal extensor GMM was strongly correlated with velocity, but peak knee internal extensor GMM was not. Knee ROM limitations may account for the increased peak knee internal extensor GMM in the knee pain group.

Aged↗
PubMedDate not supplied

Ecological validity of walking speed assessment after traumatic brain injury: a pilot study.

OBJECTIVE: To assess the ecological validity of walking speed measurement after traumatic brain injury (TBI). PARTICIPANTS: Ten people with TBI who could walk independently and were participating in a rehabilitation program. DESIGN: Walking speed on 3 clinical gait tests (comfortable and fast pace over a 10-m distance and a 6-minute walk test) in 3 "natural" environments (a corridor in a brain injury rehabilitation unit, a car park of a metropolitan shopping center, and inside a metropolitan shopping center). Normative data were collected for 275 able-bodied pedestrians as they walked in the 3 natural environments. RESULTS: For subjects with TBI, agreement between the speeds used in the clinical gait tests and the natural environments was poor (intraclass correlation coefficient [ICC] values ranged from -0.24 to 0.63). The closest speed match was the comfortable paced 10-m walk test and walking in a corridor of a brain injury rehabilitation unit (ICC 0.63). Able-bodied pedestrians walked at significantly faster speeds than did subjects with TBI in all 3 natural environments. CONCLUSIONS: Comfortable walking speed appears to have the highest ecological validity of the clinical gait tests investigated. Practice in natural and more complex environments should be incorporated into walking rehabilitation programs for people with TBI.

Adolescent↗
PubMed1987

Excitability of the soleus H-reflex arc during walking and stepping in man.

In eight normal subjects, the excitability of the soleus (Sol) H-reflex was tested in parallel with Sol length changes, EMGs of leg and thigh muscles and ground contact phases, during three different pacing movements: bipedal treadmill walking, single limb treadmill walking, and single-limb stepping on one spot. A computerized procedure was used which compensated for changes in stimulus effectiveness that occurred during free motion. In the three paradigms examined, significant excitability modulations were observed with respect to a control level determined in standing weight-bearing position. During bipedal treadmill walking, excitability was decreased in the early stance, maximally enhanced in the second half of the stance, and again decreased during the end-stance and the whole swing phase, with a minimum value around the toe off period. The main modulation pattern was retained during single-limb treadmill walking. During single-limb stepping on one spot, the stance-phase increase in excitability and the swing phase depression were still present. However, in the second half of the swing phase, reflex responsiveness returned to reference level, which was maintained during the subsequent contact period. Moreover, a decrease in reflex excitability was detected around the mid-stance. The time course of the described modulations was only partly correlated with the EMG and length changes of the Sol muscle. Furthermore, in the three movements tested, during the early stance phase, the excitability of the H-reflex arc did not correspond to the one expected on the basis of the available H-reflex studies performed under static conditions. It is suggested that, at least in certain stride phases (e.g. around the early contact period), an active regulation affects the transmission in the Sol myotatic arc during the pacing movements investigated.

Adult↗
PubMed1990

Comparison of corridor and treadmill walking in patients with severe chronic obstructive pulmonary disease.

The maximal distance walked in a given time period is frequently used as a simple method to evaluate exercise tolerance in patients suffering from chronic obstructive pulmonary disease (COPD). Typically, patients walk on a treadmill or in a corridor at a self-paced speed. Little information is available about the differences between exercise performance in patients with COPD when using the two tests. Therefore, we compared 12-minute corridor walking and 12-minute self-paced treadmill walking in 11 patients with severe COPD. Distances covered in 2, 6, and 12 minutes and walking speeds were significantly higher during corridor walking than during treadmill walking. Heart rate values during the two procedures were not significantly different, and the same degree of breathlessness was found after both walking tests. The study illustrates that corridor walking is a simple and adequate form of exercise testing. Based on heart rate responses, corridor walking appears to be more efficient than treadmill walking, possibly because patients are more familiar with walking in a corridor than on a treadmill. Corridor walking is therefore a useful method to evaluate exercise tolerance and the effects of exercise training programs in patients with COPD.

Adult↗
PubMed1998

Scoring method for assessing rate adaptive pacemakers: application to two different activity sensors.

To optimize programming of rate adaptive pacemakers (RAPs), we explored a new mathematical method to assess the performance of RAPs during daily-life tests, using customized Windows-based software. By stepwise discriminant analysis and linear regression, this method allows calculation of the acceleration and deceleration capacity of pacemakers and their general behavior during effort and recovery phases. Twenty-three patients (10 females and 13 males; 68 +/- 8 years) with chronic atrial fibrillation and a slow ventricular response were evaluated. They randomly received an accelerometer-controlled VVIR Dash Intermedics pacemaker (10 patients) or a vibration piezoelectric-controlled VVIR Sensolog III Siemens pacemaker (13 patients). All patients underwent the same test protocol: 6 minutes walking, 1.5 minutes climbing stairs, 1.5 minutes descending stairs, and 0.5 minutes sit-ups. By definition, the pacemaker responsiveness slope was programmed so that the heart rate response of paced patients during the walking test corresponded best to that of healthy controls. The slope was left unchanged for the other tests. We considered four scores: an acceleration score (EA score), an effort rate score (ER score), a deceleration score (RD score), and a recovery rate score (RR score). Scores ranged from -10 (hypochronotropic behavior of the pacemaker) to +10 (hyperchronotropic behavior), based on daily-life tests of 15 healthy controls (7 females and 8 males, 65 +/- 9 years). A score of 0 represented exact concordance with healthy controls. During stair descent, the Sensolog III produced excessive acceleration (EA score = +2.9 +/- 1.1) compared to: (1) stair climbing (EA score = -4.0 +/- 1.9; P = 0.01, with the same pacemakers); and (2) the Dash (+1.8 +/- 1.9; P = 0.04) and healthy controls (P = 0.02). The sit-up tests revealed a hypochronotropic response of both pacemakers compared to healthy controls, with a larger difference for the Sensolog III (EA score = -2.0 +/- 5.8; P = 0.04; RD score = -6.8 +/- 3.8' P = 0.02). We conclude that activity-driven pacemakers can accommodate brief activities, except for isovolumetric exercise such as sit-ups. During daily activities, accelerometer-driven pacemakers seem to provide a heart rate resoibse closer to that of healthy controls. Our new mathematical analysis is a simple and reproducible method for evaluating and quantifying the efficacy of any sensor-driven pacemaker.

Adaptation, Physiological↗