Alignment of P waves for signal averaging.

Area of Science:

• Cardiology
• Biomedical Engineering
• Signal Processing

Background:

• Signal-averaged atrial activity from body surface is increasingly used for assessing atrial arrhythmias.
• Precise waveform alignment is crucial for accurate signal averaging.

Purpose of the Study:

• To compare the alignment accuracy of wide (0.01-300 Hz) and narrow (10-300 Hz) bandpass filtered P waves from body surface recordings.
• To determine the impact of filtering on the analysis of signal-averaged P waves.

Main Methods:

• Surface P waves and atrial electrograms from temporary pacing wires were recorded in 15 patients.
• Beat-by-beat alignment error was calculated for 100 beats using wide and narrow bandpass filters.
• Filtered P waves were compared to atrial electrograms for alignment accuracy.

Main Results:

• The standard deviation of alignment error for wide filtered surface P waves was 1.7 +/- 0.8 ms.
• The standard deviation of alignment error for narrow filtered P waves was significantly lower at 0.8 +/- 0.4 ms.
• Narrow bandpass filtering demonstrated superior alignment accuracy.

Conclusions:

• High-pass filtering significantly improves the alignment accuracy of signal-averaged P waves.
• Enhanced alignment accuracy leads to improved frequency resolution for P wave analysis.
• Narrow bandpass filtering is recommended for more precise assessment of atrial arrhythmias using signal-averaged P waves.