Determination of the conduction paths from the left to the right atrium using frequency analysis of atrial electrograms in two canine models of atrial fibrillation

Studies of atrial fibrillation (AF) have demonstrated that a stable rhythm of very short cycle length in the left atrium (LA) can cause a fibrillatory conduction in the right atrium (RA). We tested the hypothesis that FFT analysis of atrial electrograms (AEGs) during AF will rapidly and reliably identify the LA to RA conduction path(s). During induced AF, four sec recording segments from 203 bipolar AEGs were subjected to FFT to obtain the frequency analysis. FFT analysis of AF showed a dominant frequency peak in the LA and multiple frequency peaks in the RA. Conduction paths to the RA varied from study-to-study, and were found between the superior vena cava and the right superior pulmonary vein (RSPV), between the RSPV and the right inferior pulmonary vein (RIPV), between the RIPV and the inferior vena cava (IVC), under the IVC, and from Bachmann's bundle to the right atrial appendage. These conduction paths identified by FFT analysis corresponded to the conduction paths found in activation sequence mapping. FFT analysis allowed rapid and reliable detection of the LA to RA conduction paths in AF.