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Evaluation of a new sensor-based algorithm to protect against atrial arrhythmias
Pacing and Clinical Electrophysiology : PACE
|November 1, 1996
Summary
The SmarTracking algorithm can cause Wenckebach behavior in patients with healthy hearts. Adjusting the sensor-calculated rate (SCR) and pacing rate settings can optimize performance and prevent issues during rest and exercise.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Device Technology
Background:
- The SmarTracking (ST) algorithm utilizes sensor-calculated rate (SCR) to establish a variation band for intrinsic sinus rates in pacemakers.
- When sinus rate surpasses the upper limit of this band, the ST rate (STR) limits ventricular pacing, potentially inducing Wenckebach behavior.
Purpose of the Study:
- To evaluate the behavior of the ST algorithm's Wenckebach mechanism in patients with healthy sinus nodes.
- To assess ST algorithm performance during both rest and exercise conditions.
Main Methods:
- Twenty-one patients with normal sinus function were enrolled.
- Heart rate data were collected using the implanted pacemaker's rate profile and a calibrated external pacemaker for STR and SCR.
- A 15-minute protocol involved alternating periods of walking and rest.
Main Results:
- At nominal settings, the difference between STR and sinus rate (DST) remained positive (≥20%), with Wenckebach behavior observed in 5 patients at rest and 3 during heavy exercise.
- Increasing the resting STR to 95 ppm and maximum pacing rate to 150 ppm reduced Wenckebach occurrences to zero for most activities, with only one instance during a very fast walk.
Conclusions:
- Generally, no significant competition occurred between the ST rate and intrinsic rhythm.
- Reprogramming of the resting STR and maximum pacing rate was necessary in some cases for optimal pacemaker performance.