METHODSInclusion Criteria:• Age > 18 years• CI defined as average HR<55 BPM on 24

hour Holter, AF< 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 MethodsT-test and Wilcoxen Signed-Ranks test for paired data

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

RESULTS• 18 pts enrolled over 28 months, 10 male• Mean age=74.8 (60-86) years• 4/18 rejected due to:

• >50% AF in 2• No CI in 1 (<60% 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

ENDPOINTSQuality of Life (QoL) scores: 0 = No improvement over baseline1 = “Modest” improvement2 = “Significant” improvement3 = “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

Behzad B. Pavri, MD, Sarah Russell, RN Thomas Jefferson University Hospital, Philadelphia

• 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.

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

QUALITY OF LIFE Baseline

DDD-CLS DDDR

p value(CLS vs. DDDR)

Score 0 1.9 0.8 0.006

HOLTERHEART RATE

(bpm) BaselineDDD-CLS DDDR

p valve(BL vs. CLS)

p value (BL vs. DDDR)

p value (CLS vs. DDDR)

Holter Mean HR 56.3 71.9 64.7 0.002 0.004 0.046

Holter Minimum HR 40.3 57.2 57.3 <0.001 <0.001 0.681

Holter Maximum HR 91.6 116.3 106.7 0.002 0.058 0.092

Sample 24 Hour HR Trends in same patient

• 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

• Accelerometer (DDDR) provides HR increase with detection of oscillation

• The Ansar System provides a “snapshot” of sympathovagal balance during standard maneuvers

CONCLUSIONS CLS DDDR

ANSARHEART RATE

(bpm) BaselineDDD-CLS DDDR

T testp value

(CLS vs. DDDR)

Wilcoxen testp value

(CLS vs. DDDR)

Resting 55.8 70.0 60.8 <0.001 0.004

Isometric Handgrip 59.4 71.9 62.3 <0.001 0.004

Deep Breathing 58.0 71.2 60.9 <0.001 0.004

Valsalva maneuver 57.1 73.1 61.6 <0.001 0.004

Postural Change 58.1 73.0 64.3 0.015 0.039