Analysis of high gain signal-averaged P/A wave time domain parameters recorded from external leads (SA-ECG) and internal electrograms (SA-IEGM) recorded from three right- and left-intraatrial leads.

BACKGROUND Time-domain analysis of the P-wave in signal-averaged ECG (SA-ECG) recorded from chest leads is an accepted method for evaluating the inhomogeneity of atrial excitation, predictive for atrial arrhythmias. The aim of the study was to determine the value of the SA-ECG technique for intraatrial signal processing. Additional aims were to evaluate the correlation between SA-ECG parameters (external and intraatrial) and the frequency of atrial fibrillation recurrences, ongoing antiarrhythmic therapy and LA diameter. METHODS Recordings were performed in 24 pts during biatrial pacing system implantation. A surface SA-ECG was obtained from orthogonal leads, and intraatrial signals were recorded and averaged separately from the right and left atrium. We analyzed standard SA-ECG parameters (P/A wave duration, RMS20 and LAS5) and the presence of atrial late potentials (ALP-Pdur > 125 ms and RMS20 < 2.40 mV). RESULTS AND CONCLUSIONS Intraatrial SA-ECG provides accurate data for ALP analysis, mostly due to its improved signal quality and QRS discrimination. P-duration and RMS20 seem to be parameters with good correlation between external and internal SAECG. Intraatrial SAECG offers a valuable tool to evaluate abnormalities of the final part of atrial excitation. There are no straight associations between SA-ECG parameters and arrhythmic burden, ongoing antiarrhythmic therapy and LA diameter. (Cardiol J 2007; 14: 287-300).