CLEAR (CLS)

CLEAR

Cylos Responds with Physiologic Rate Changes During Daily Activities

Abi-Samra et al., Europace 2012

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Study Design

  • Randomized, prospective, single-blinded, multi-center study
  • Compare the performance and physiological response of the Closed Loop Stimulation (CLS) rate-adaptive sensor to accelerometer (XL) and no rate sensor (DDD) during typical daily activity testing.
  • 1,491 patients at 98 US sites

Key Result 1

Subjects were able to sweep a statisically greater area (average of 1.6 m2 or 17.2 ft2) while in CLS as compared with accelerometer (XL) or no rate sensor (DDD).¹ The distance walked was not statistically different for CLS as compared to XL or DDD. Heart rates obtained during testing in CLS were statistically higher than the mean heart rates obtained during testing in XL or DDD.¹ Overall, CLS provides benefits over accelerometer (XL) and no rate sensor (DDD) in patients requiring ≥80% pacing. Specifically, subjects were able to sweep more area, had a reduced prevalence of OH as indicated by a closer to ‘normal’ heart rate, during both the walk and sweep activities.¹

Key Result 2

Use of CLS resulted in over a 75% reduction in the prevalence of orthostatic hypotension after standing 1 minute as compared with XL and DDD.

Clinical Relevance

  • In this elderly deconditioned population, the beneficial effects of an enhanced chronotropic response were more evident in lower energy activities (CLS effect was most prominent in the stand and go test, least with the walk test).
  • This study raises a legitimate question regarding the need of a more ‘tuned’ definition of chronotropic incompetence.
Reference no.
  • NCT00355797
Study Objective
  • Investigated the effectiveness of Closed Loop Stimulation (CLS) rate responsive technology over both standard rate responsive technology (accelerometer) and non-rate responsive pacing modes during Activities of Daily Living (ADL)
1° Endpoints
  • Evaluate a composite of the percent change in ADL performance during the 6-minute walk test and sweeping test combined
  • Evaluate the percent change in pulse pressure during the orthostatic test
2° Endpoints
  • Compare a variety of outcome measures over a 12-month period between a CLS and a rate responsive pacing mode. The outcome measures include changes in: QOL - 6-minute walk test distance - Mode reprogramming - AF burden - Cardiac symptoms - NYHA class
  • Compare a variety of outcome measures over a 12-month period between a CLS and a non-rate responsive mode. The outcome measures include changes in: QOL - 6-minute walk test distance - Mode reprogramming - AF burden - Cardiac symptoms - NYHA class
  • Evaluate a composite of the percent change in cardiac response during the 6-minute walk test and sweeping test combined
  • Evaluate the percent change in cardiac response during the orthostatic test
Clinical Sites
  • 98 US Sites
Inclusion Criteria
  • Implanted within the last 45 days or being considered for implant with a BIOTRONIK pacemaker utilizing CLS rate responsive technology (currently the Cylos family of pacemakers)
  • Ability to give written informed consent
  • Geographically stable and able to return for regular follow-ups for 12 months after ADL testing or enrollment
  • At least 18 years old
Main Exclusion Criteria
  • Patients physically limited and unable to perform all or parts of the ADL testing
  • Currently enrolled in any other clinical study
  • Patients with medical reasons that preclude regular participation in the follow-ups
Devices
  • Pacemaker utilizing CLS (Cylos family of pacemakers)
  • Legally marketed pacing leads
Follow-Up
  • Every 6 months for 1 year
Study Duration
  • May 2006 - December 2010

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1 Abi-Samra F, Singh N, Rosin B, Dwyer J, Miller C; Effect of rate-adaptive pacing on performance and physiological parameters during activities of daily living in the elderly: results from the CLEAR (Cylos Responds with Physiologic Rate Changes during Daily Activities) study, Europace, Feb 2013;15(6):849-856