METHODS

1
An Impedance Sensor (CLS) is Superior to an
Accelerometer for Chronotropically Incompetent
Patients with Sinus Node Dysfunction Results of
a Pilot Study with a Dual Sensor Pacemaker
Behzad B. Pavri, MD, Sarah Russell, RN
Thomas Jefferson University Hospital, Philadelphia
ENDPOINTS Quality of Life (QoL) scores 0 No
improvement over baseline 1 Modest
improvement 2 Significant improvement 3
Tremendous improvement Holter Data mean,
minimum, and maximum HR Ansar Data HR and
autonomic data during rest isometric handgrip,
deep breathing, Valsalva, and postural change
(standing)

• INTRODUCTION
• Patients (pts) with chronotropic incompetence
  (CI) depend on pacemakers (PM) for rate response
• Many sensors do not provide physiologic heart
  rate (HR) response
• The Biotronik Protos PM has 2 independent
  sensors
• Impedance sensor - DDD-CLS
• Accelerometer - DDDR
• Closed Loop Stimulation (DDD-CLS) monitors local
  RV myocardial-blood pool impedance as a surrogate
  for contractility

• Accelerometer (DDDR) provides HR increase with
  detection of oscillation
• The Ansar System? provides a snapshot of
  sympathovagal balance during standard maneuvers

• OBJECTIVE AND HYPOTHESIS
• To compare the HR response provided by an
  accelerometer (DDDR) to Closed Loop Stimulation
  (DDD-CLS) in pts with chronotropic incompetence
• DDD-CLS provides more physiologic HR behavior
  compared to DDDR

• RESULTS
• 18 pts enrolled over 28 months, 10 male
• Mean age74.8 (60-86) years
• 4/18 rejected due to
• gt50 AF in 2
• No CI in 1 (lt60 atrial pacing at f/u)
• Intercurrent illness and hospitalizations in 1
• 9/14 pts with analyzable data ? completed study
• All pts had normal LV ejection fraction
• 6 randomized to DDDR first, 3 to CLS first
• CLS ? 7/9 pts Significant or Tremendous
  improvement
• DDDR ? 2/9 pts Significant improvement
• 7/9 blinded pts opted for CLS sensor

• METHODS
• Inclusion Criteria
• Age gt 18 years
• CI defined as average HRlt55 BPM on 24 hour
  Holter, AFlt 20
• Single blind, randomized cross-over trial
• Randomized to DDDR or CLS for 4 wks each.
  Assessed at the end of each 4 wk period. Pts
  served as their own controls
• PM programming identical in both modes except for
  sensor type
• Statistical Methods
• T-test and Wilcoxen Signed-Ranks test for paired
  data

• CLS establishes baseline impedance curves (at
  rest)
• CLS collects impedance curves with each heart
  beat, and calculates area deviation from baseline
  curve
• Pacing rate is based on deviation from baseline
  curve

Sample 24 Hour HR Trends in same patient
CLS DDDR
CONCLUSIONS

• DDD-CLS provided better QoL and was selected as
  sensor of choice by the majority of blinded
  patients.
• DDD-CLS provided superior HR response to
  standardized autonomic maneuvers as assessed by
  Ansar testing.
• Although Holter-derived minimum and maximum HR
  were not significantly different between the two
  sensors, DDD-CLS provided higher mean HR.