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. 2006 Jan;11(1):12-9.
doi: 10.1111/j.1542-474X.2006.00058.x.

High-resolution analysis of the surface P wave as a measure of atrial electrophysiological substrate

Damian P Redfearn  1 , Joanne Lane, Kevin Ward, Peter J Stafford
Affiliations

High-resolution analysis of the surface P wave as a measure of atrial electrophysiological substrate

Damian P Redfearn et al. Ann Noninvasive Electrocardiol. 2006 Jan.

Abstract

Background: At present atrial electrophysiology can only be assessed by invasive study. This limits available data in humans concerning atrial electrophysiologic changes in disease and in response to intervention. Indirect evidence suggests that the signal-averaged P wave (SAPW) may provide noninvasive markers of atrial electrophysiology but no direct evaluations that measure both refractoriness and conduction time have been reported.

Methods: We investigated 9 patients attending for diagnostic electrophysiological studies (4 male; mean age 35.7 years). A 20-pole catheter was positioned in the right atrium; a decapole catheter was placed in the coronary sinus. Atrial effective refractory period (AERP) and conduction times were measured at the lateral and septal right atrium and the left atrium during sinus rhythm (SR) and at pacing cycle lengths of 600, 500, and 400 ms. Simultaneous SAPW recordings were taken during SR and pacing at 600 ms. Intravenous flecainide (2 mg/kg) was given after which the protocol was repeated.

Results: Flecainide slowed conduction significantly at all sites (P < 0.05). During baseline measurements, rate adaptation of AERP was observed (P < 0.02 at the septum). Flecainide increased filtered P wave duration (P < 0.05) and reduced P wave energies (P < 0.05). Negative correlation was observed between P wave energies and conduction time with an inverse relationship between high-frequency energy and left atrial AERP.

Conclusions: The SAPW provides a noninvasive marker of atrial electrophysiology.

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Figures

Figure 1
Figure 1
Power density spectrum and filtered P wave before and after the administration of flecainide. Graphic examples of data from the same patient. Power density spectra are displayed on top with lines after the bulk of the spectra marking first 60 Hz and then 80 Hz on each graph. The high‐frequency components after the lines are clearly seen to diminish after flecainide. Time‐domain surface filtered P wave duration is observed to prolong in the corresponding images below.
See this image and copyright information in PMC

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