Spectral Analysis of Endocardial Electrogram on the High-Lateral Right Atrium during Sinus Rhythm and Pacing stimuli: The Relationship between the Frequency Spectrum of Atrial Wave and the Occurrence of Atrial Fibrillation

The provocation of atrial fibrillation (Af) was studied in 23 patients by 10 single extrastimulations, and by rapid pacing over three minutes at the mid-lateral right atrium. The frequency spectrum of atrial electrogram on the high- lateral right atrium (HRA) was simultaneously computed with the fast-Fourier transform analysis. Result were shown as follows: 1) The single extrastimulation induced no Af in any patients, but rapid pacing induced Af in 20 patients with various heart diseases and the shorter interval of atrial effective refractory period (AERP). 2) All of the 5 patients with a history of transient Af had significantly shorter AERP of the right atrium than that in patients without a history of Af. 3) During both single extrastimulation and rapid pacing, both the higer- and lower-frequency components of atrial electrogram in patients with induction of Af were greater in amplitude than those in patients without induction of Af. The patients with induction of Af by pacing of may have the vulnerable electrophysiologic condition around the region of HRA, probably related to the higher sensitivity of right atrium to the pacing stimuli, regardless of the basal heart disease.

Atrial fibrillation

Atrial vulnerability

Frequency analysis

Rapid pacing

Fragmentation