Abstract 3515: An Impedance Sensor is Superior to an Accelerometer for Chronotropically Incompetent Patients with Sinus Node Dysfunction: Results of a Pilot Study with a Dual Sensor Pacemaker
Background: Patients (pts) with implanted pacemakers (PM) for chronotropic incompetence (CI) depend on sensor-driven increase in heart rate (HR), but many current sensors do not provide physiologic responses in all situations. The Biotronik Protos PM has 2 sensors: an accelerometer (DDDR) which detects linear motion, and a Closed Loop Sensor (DDD-CLS) that monitors myocardial/blood-pool impedance as a surrogate for contractility. This study prospectively assessed HR response in CI pts and a PM with both sensors.
Hypothesis: DDD-CLS provides more physiologic heart rate behavior compared to DDDR.
Methods: Blinded, randomized, crossover study. INCLUSION CRITERIA: Age>18 yrs, CI defined by mean HR<55 bpm, maximum HR<90 bpm on Holter; paroxysmal atrial fibrillation (PAF) <20%. Pts were assigned to DDDR or DDD-CLS for 4 wks each, and served as their own controls; PM programming was identical except for the sensor. Quality of Life scores assessed as: no/minimal improvement from baseline=0, modest improvement=1, significant improvement=2, tremendous improvement=3. HR response was assessed prior to PM implantation, during DDDR, and during DDD-CLS with 24 hr Holters and by autonomic testing (Ansar system) where ECG, HR and BP were monitored at rest, and during standardized autonomic maneuvers: isometric handgrip, deep breathing, Valsalva, and postural change (standing).
Results: We enrolled 15 pts (6 male), mean age=72.9±10.6 (range=47–84) yrs, all with normal LVEF; 3 pts were excluded due to: >50% PAF, no CI (<60% atrial pacing at f/u), and prolonged in-hospital illness. Of 12 pts with analyzable data, 7 had DDDR first, and 5 had DDD-CLS first. See Table⇓
Conclusions: Although mean, minimum and maximum HR on 24 hour Holter were identical with DDD-CLS and DDDR, HR modulation during autonomic maneuvers was superior with DDD-CLS compared to DDDR. HR change during autonomic maneuvers and trends/ histograms from Holter/PM logs with DDD-CLS closely mimicked normal HR behavior.