A comparison of external rate responsive pacemakers with identical implanted units

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Accelerometer-based pacemakers (DDDR) automatically adjust heart rate based on physical activity.
• Assessing the accuracy of external devices to predict implanted pacemaker function is crucial for patient management.

Purpose of the Study:

• To compare the rate response of implanted DDDR pacemakers with identically programmed external pacemakers during exercise.
• To determine if an external pacemaker can reliably predict the performance of an implanted unit.

Main Methods:

• Seven patients with implanted DDDR pacemakers were tested simultaneously with an external pacemaker.
• Pacemaker sensitivity was calibrated, and pacing rates were recorded during a 15-minute exercise test (walking, stairs) and a 3-minute recovery period.
• Pacing rates were compared at specific intervals: 2 minutes, 4 minutes, peak exercise, and 3 minutes post-exercise (decay).

Main Results:

• Both implanted and external pacemakers showed comparable pacing rates across all measured intervals (2 min, 4 min, peak, decay).
• Mean differences in pacing rates (ppm) between the two devices were small and within confidence intervals.
• A high-confidence correlation was observed between the implanted and external pacemaker units in all patients.

Conclusions:

• An external pacemaker can accurately predict the rate response of an accelerometer-based DDDR pacemaker.
• No adjustments to pacing parameters are needed when using an external unit for assessment.
• External pacemakers serve as a reliable tool for evaluating implanted device performance.