Peak Cardiopulmonary Performance Research Articles

Less is more: Can we achieve cardiac resynchronization with 2 leads only?

BackgroundWe compared clinical and technical outcome of CRT recipients treated either with a conventional 3‑leads (3L) CRTD or with the new 2‑leads (DX) CRTD that enables atrial signal detection by a floating dipole built on a pentafilar RV lead. MethodsEchocardiography and cardiopulmonary exercise tests were repeated either before CRTD implantation and between 6 and 12 months follow up in consecutively implanted patients who had a resting heart rate>40bpm at maximum tolerated beta-blocker dosage. HF status, reverse LV remodeling, exercise tolerance and chronotropic incompetence were assessed at 12 months FU. Device diagnostics were obtained twice yearly until December 2016. Results37 patients aged 66 (58–73) years were consecutively implanted in 2013–2014 according to current guidelines, 25 with a 3L CRTD and 12 with a DX CRTD. Beta-blocker dosage was similar, and no difference between the 2 groups was observed in terms of NYHA class improvement, LV reverse remodeling, peak cardiopulmonary performance and presence of chronotropic incompetence at 12 months follow up. There was no difference in: amount delivered CRT; occurrence of VT/VF; occurrence of AT/AF. No patients developed need of atrial stimulation at 3-years FU. Atrial undersensing never occurred in any patient, whereas Far-field R-wave oversensing was more common in 3L patient than in DX patients (8/25 vs none, P<0.05). P wave amplitude was greater in DX vs 3L patients [5.1(3.7–9.2) vs 2.9(2–3.9) mV, P<0.01]. ConclusionCRT can be achieved with two‑leads-only in the majority of patients, provided that indication to atrial stimulation is ruled out.

Efficacy of Feedback-Controlled Robotics-Assisted Treadmill Exercise to Improve Cardiovascular Fitness Early After Stroke: A Randomized Controlled Pilot Trial.

Cardiovascular fitness is greatly reduced after stroke. Although individuals with mild to moderate impairments benefit from conventional cardiovascular exercise interventions, there is a lack of effective approaches for persons with severely impaired physical function. This randomized controlled pilot trial investigated efficacy and feasibility of feedback-controlled robotics-assisted treadmill exercise (FC-RATE) for cardiovascular rehabilitation in persons with severe impairments early after stroke. Twenty individuals (age 61 ± 11 years; 52 ± 31 days poststroke) with severe motor limitations (Functional Ambulation Classification 0-2) were recruited for FC-RATE or conventional robotics-assisted treadmill exercise (RATE) (4 weeks, 3 × 30-minute sessions/wk). Outcome measures focused on peak cardiopulmonary performance parameters, training intensity, and feasibility, with examiners blinded to allocation. All 14 allocated participants (70% of recruited) completed the intervention (7/group, withdrawals unrelated to intervention), without serious adverse events occurring. Cardiovascular fitness increased significantly in both groups, with peak oxygen uptake increasing from 14.6 to 17.7 mL · kg · min (+17.8%) after 4 weeks (45.8%-55.7% of predicted maximal aerobic capacity; time effect P = 0.01; no group-time interaction). Training intensity (% heart rate reserve) was significantly higher for FC-RATE (40% ± 3%) than for conventional RATE (14% ± 2%) (P = 0.001). Substantive overall increases in the main cardiopulmonary performance parameters were observed, but there were no significant between-group differences when comparing FC-RATE and conventional RATE. Feedback-controlled robotics-assisted treadmill exercise significantly increased exercise intensity, but recommended intensity levels for cardiovascular training were not consistently achieved. Future research should focus on appropriate algorithms within advanced robotic systems to promote optimal cardiovascular stress.Video abstract available for more insights from the authors (Supplemental Digital Content 1, http://links.lww.com/JNPT/A107).

Comparison of peak cardiopulmonary performance parameters on a robotics-assisted tilt table, a cycle and a treadmill.

Robotics-assisted tilt table (RATT) technology provides body support, cyclical stepping movement and physiological loading. This technology can potentially be used to facilitate the estimation of peak cardiopulmonary performance parameters in patients who have neurological or other problems that may preclude testing on a treadmill or cycle ergometer. The aim of the study was to compare the magnitude of peak cardiopulmonary performance parameters including peak oxygen uptake (VO2peak) and peak heart rate (HRpeak) obtained from a robotics-assisted tilt table (RATT), a cycle ergometer and a treadmill. The strength of correlations between the three devices, test-retest reliability and repeatability were also assessed. Eighteen healthy subjects performed six maximal exercise tests, with two tests on each of the three exercise modalities. Data from the second tests were used for the comparative and correlation analyses. For nine subjects, test-retest reliability and repeatability of VO2peak and HRpeak were assessed. Absolute VO2peak from the RATT, the cycle ergometer and the treadmill was (mean (SD)) 2.2 (0.56), 2.8 (0.80) and 3.2 (0.87) L/min, respectively (p < 0.001). HRpeak from the RATT, the cycle ergometer and the treadmill was 168 (9.5), 179 (7.9) and 184 (6.9) beats/min, respectively (p < 0.001). VO2peak and HRpeak from the RATT vs the cycle ergometer and the RATT vs the treadmill showed strong correlations. Test-retest reliability and repeatability were high for VO2peak and HRpeak for all devices. The results demonstrate that the RATT is a valid and reliable device for exercise testing. There is potential for the RATT to be used in severely impaired subjects who cannot use the standard modalities.

Cardiopulmonary performance testing using a robotics-assisted tilt table: Feasibility assessment in able-bodied subjects

Robotics-assisted tilt table technology was introduced for early rehabilitation of neurological patients. It provides cyclical stepping movement and physiological loading of the legs. The aim of the present study was to assess the feasibility of this type of device for peak cardiopulmonary performance testing using able-bodied subjects. A robotics-assisted tilt table was augmented with force sensors in the thigh cuffs and a work rate estimation algorithm. A custom visual feedback system was employed to guide the subjects' work rate and to provide real time feedback of actual work rate. Feasibility assessment focused on: (i) implementation (technical feasibility), and (ii) responsiveness (was there a measurable, high-level cardiopulmonary reaction?). For responsiveness testing, each subject carried out an incremental exercise test to the limit of functional capacity with a work rate increment of 5 W/min in female subjects and 8 W/min in males. 11 able-bodied subjects were included (9 male, 2 female; age 29.6 ± 7.1 years: mean ± SD). Resting oxygen uptake (O<formula>_{2}</formula>) was 4.6 ± 0.7 mL/min/kg and O<formula>_{2}</formula>peak was 32.4 ± 5.1 mL/min/kg; this mean O<formula>_{2}</formula>peak was 81.1% of the predicted peak value for cycle ergometry. Peak heart rate (HRpeak) was 177.5 ± 9.7 beats/min; all subjects reached at least 85% of their predicted HRpeak value. Respiratory exchange ratio (RER) at O<formula>_{2}</formula>peak was 1.02 ± 0.07. Peak work rate) was 61.3 ± 15.1 W. All subjects reported a Borg CR10 value for exertion and leg fatigue of 7 or more. The robotics-assisted tilt table is deemed feasible for peak cardiopulmonary performance testing: the approach was found to be technically implementable and substantial cardiopulmonary responses were observed. Further testing in neurologically-impaired subjects is warranted.

Cardiopulmonary responses to robotic end-effector-based walking and stair climbing

BackgroundA recently developed robotic end-effector device (G-EO system, Reha Technology AG) can simulate walking and stair climbing. This approach has the potential to promote cardiovascular exercise training during rehabilitation. The aim of this study was to characterise cardiopulmonary responses of end-effector-based exercise in able-bodied subjects and to evaluate the feasibility of intensity-guided exercise testing. MethodsFive healthy subjects aged 33.7±8.8 years (mean±SD) performed a constant load test and an intensity-guided incremental exercise test. The outcome measures were steady-state and peak cardiopulmonary performance parameters including oxygen uptake (VO2) and heart rate (HR). ResultsPassive end-effector-based stair climbing (VO2=13.6±4.5mL/min/kg, HR=95±23beats/min) showed considerably lower cardiopulmonary responses compared to reference data (VO2=33.5±4.8mL/min/kg, HR=159±15beats/min). Peak performance parameters during intensity-guided incremental exercise testing were: VO2=35.8±5.1mL/min/kg and HR=161±27 beats/min, corresponding to a relative VO2=76.0±18.7% of predicted aerobic capacity and a relative HR=87.3±14.5% of age-predicted HR maximum. ConclusionEnd-effector-based exercise is a promising method for the implementation of cardiovascular exercise. Although end-effector-based stair climbing evoked lower cardiopulmonary responses than conventional stair climbing, active contribution during exercise elicited substantial cardiopulmonary responses within recommended ranges for aerobic training.

Cardiopulmonary performance testing using a robotics-assisted tilt table: feasibility assessment in able bodied subjects

Purpose: Robotics-assisted tilt table technology with integrated leg drives for basic stepping functionality is clinically available for patients with neurological impairments. Initially introduced for early rehabilitation, it provides cyclical stepping movement and physiological loading in immobilized patients. This technology provides stability and support in patients with neurological disorders for whom weakness, balance and coordination problems would preclude cardiopulmonary performance testing using a treadmill or cycle ergometer. This type of device may facilitate the estimation of peak oxygen uptake and other important cardiopulmonary performance parameters in patients who have neurological deficits. The aim of the present study was to assess the feasibility and safety of this device for peak cardiopulmonary performance testing in able-bodied subjects. Methods: A robotics-assisted tilt table (Erigo, Hocoma AG, Switzerland) was augmented with force sensors in the thigh cuffs and a work rate estimation algorithm. A custom visual feedback system was employed to guide the subjects' work rate and to provide real time feedback of actual work rate. Each subject carried out an incremental exercise test to the limit of functional capacity with a work rate increment of 5 W/minute in female subjects and 8 W/minute in males. Outcome measures were peak oxygen uptake (VO2peak), peak heart rate (HRpeak), respiratory exchange ratio (RER), peak work rate (WRpeak) and the Borg CR10 scale to measure exertion and leg fatigue. Results: 11 able-bodied subjects were included (9 male, 2 female; age 29.6±7.1 years: mean ± SD). Resting VO2 was 4.6±0.7 ml/kg/min and VO2peak was 32.4±5.1 ml/kg/min. All participants reached at least 85% of their predicted HRmax value. RER at peak VO2 was 1.02±0.07. Eight participants (72.7%) reached their peak VO2 in 8-12 minutes, which is considered the optimal duration. The average WRpeak was 65.7 W for males and 41.5 W for females. All participants reported a Borg CR10 value for exertion and leg fatigue of 7 or more. There were no serious adverse events. Conclusions: The robotics-assisted tilt table augmented with work rate estimation and a visual feedback system is a feasible and safe method for peak cardiopulmonary performance testing in able-bodied subjects. Future work will evaluate test-retest reliability and compare peak cardiorespiratory performance values with those obtained from a treadmill and a cycle ergometer. The approach will then be piloted in subjects with neurological impairments.

Comparison of peak cardiopulmonary performance parameters during robotics-assisted treadmill exercise and arm crank ergometry in incomplete spinal cord injury

(i) to compare cardiopulmonary performance parameters obtained from incremental exercise tests (IETs) performed using a robotics-assisted treadmill and an arm crank ergometer; (ii) to investigate test-retest reliability during both modes of exercise. Each participant performed two IETs to the limit of tolerance on both a robotics-assisted treadmill and an arm crank ergometer. A Spinal Injuries Unit in the United Kingdom. 10 people with an incomplete spinal cord injury (SCI). Not applicable. Peak oxygen uptake (VO(2peak)), the gas exchange threshold (GET), peak heart rate (HR(peak)) and peak lactate (Lactate(peak) were obtained for each mode of assessment. The mean responses and test-retest reliability of the main outcome measures were determined and compared between modes of assessment. VO(2peak) was 16% higher (p = 0.016) and the VO2 at the GET was 40% higher (p = 0.007) during the robotics-assisted treadmill exercise (RATE) IET. There was a trend for HR(peak) to be higher during arm crank ergometry (ACE) (p = 0.058). Lactate(peak) was 46% higher (p = 0.006) during the ACE IET. During robotics-assisted exercise, the test-retest reliability was very high for VO2(peak) (r = 0.95), high for the GET (r = 0.75) and HR(peak) (r = 0.88), and moderate for Lactate(peak) (r =0.58). For ACE, the test-retest reliability was very high for VO(2peak) (r = 0.93), high for HR(peak) (r = 0.81) and Lactate(peak) (r = 0.78), and low for the GET (r = 0.16). The results suggest that, when compared with ACE,RATE can be a highly effective stressor of the cardiopulmonary system, and may be a more appropriate mode of assessment to determine and monitor cardiopulmonary fitness in people with incomplete SCI.

Comparison of peak cardiopulmonary performance parameters during robotics-assisted treadmill exercise and arm crank ergometry in incomplete spinal cord injury

Objective: (i) to compare cardiopulmonary performance parameters obtained from incremental exercise tests (IETs) performed using a robotics-assisted treadmill and an arm crank ergometer; (ii) to in...