Atrial Near‐Field and Ventricular Far‐Field Analysis by Automated Signal Processing at Rest and During Exercise

Abstract

Introduction: Sophisticated monitoring of atrial activity is a prerequisite for modern pacemaker therapy. Ideally, near‐fields and ventricular far‐fields ought to be distinguished by beat‐to‐beat template analysis of the atrial signal. A prerequisite is that atrial signals are stable under different conditions. Methods and Results: A Matlab routine was developed to analyze atrial electrograms of 23 patients at least 3 months after implantation of a dual chamber pacemaker under several conditions including at rest, bipolar at rest, in an upright position, during treadmill exercise, and postexercise. A near‐field and far‐field template was created and amplitudes, widths, and slew rates were measured. In bipolar configuration, near‐field amplitude at rest was 3.04 ± 0.94 mV (unipolar)/3.36 ± 1.0 mV (bipolar) versus 3.18 ± 1.0 mV (bipolar) at peak exercise. Far‐field amplitude at rest was 1.66 ± 1.18 (unipolar)/0.47 ± 0.27 mV (bipolar) and 0.41 ± 0.21 mV (bipolar) at peak exercise (n.s. for bipolar measurements). No overall significant changes were observed for near‐ and far‐field widths and slew rates during exercise. Shorter tip‐ring distances of the atrial bipole, lead position, and the presence of sinus node disease did not have any impact on overall near‐ and far‐field signal characteristics. Intraindividual differences between rest and peak exercise were moderate (range: near‐field +0.15 to −0.54 mV; range: far‐field +0.05 to −0.18 mV). Conclusions: Atrial near and far fields can be automatically classified and quantified by automated signal processing. Signals did not change during exercise or change of posture. This is a prerequisite for the implementation of beat‐to‐beat template analysis into pacemakers.

Keywords

• P wave
• ventricular far‐field
• signal processing
• atrial leads
• morphology analysis
• dual‐chamber pacemaker