High resolution analysis of the P wave

A method for averaging the P wave is proposed. This method has been tested against the esophageal recordings. Due to the large deflection of the P wave on the electrode placed into the esophagus, esophageal recordings were considered as reliable references for determination of the alignment accuracy of the proposed method. An attempt was made to quantify the high frequency content of the P wave. P wave averages were obtained from surface X, Y, Z recordings of 67 patients which comprised normals, patients with atrial arrhythmias, and patients with left atrial dilatation, and the high frequency content of the averaged P waves was quantified using filtered P wave duration and root mean square (RMS) value of the vector magnitude in the last 20 milliseconds