Wavelength Index at Three Atrial Sites in Patients with Paroxysmal Atrial Fibrillation

Abstract

The purpose of this study was to evaluate the wavelength index (WLI) at three atrial sites in a group of 23 patients with recurrent episodes of lone paroxysmal atrial fibrillation (LPAF) and a control group (n = 20). All patients underwent programmed atrial stimulation (paced cycle length = 600 ms) at high, medium, and low lateral right atrial wall. P wave duration, sinus cycle length, and corrected sinus node recovery time were not significantly different between the two study groups. WLI was calculated according to the following formulas: atrial effective refractory period (AERP)/duration of atrial extrastimulus electrogram (A2) or AERP/A2 + atrial latency; and atrial functional refractory period (AFRP)/A2. WLI was significantly shorter in LPAF than in the control group at each of the paced atrial sites independently of the formula used. Duration of premature atrial electrogram appeared to play the major role in determining the difference in WLI between patients with paroxysmal atrial fibrillation and the control group.

Age-Related Changes in the Electrophysiologic Properties of the Atrium in Patients with no History of Atrial Fibrillation

“…Some previous studies found that a shorter wavelength index indicated greater vulnerability to atrial fibrillation. 10,14,16) In this study, the wavelength index was shorter in patients with inducible atrial fibrillation than in those without inducible atrial fibrillation, which is consistent with these previous reports. However, we found no correlation between the wavelength index and age, which is the first time this finding has been described.…”

“…Although the effects of the underlying diseases on atrial vulnerability might not be negligible, this is a limitation common to many studies. 7,14,16) In this study, we found no difference with respect to age between patients with and without inducible atrial fibrillation, which is not concordant with previous reports. 1,2) The reason for this discrepancy might be due to the underlying arrhythmias.…”

“…Although several parameters, such as the atrial refractory period, fragmented atrial activity, atrial conduction delay, repetitive atrial firing, wavelength index, and inducibility of atrial fibrillation have been proposed as indices of atrial vulnerability, it remains uncertain whether these indices also represent inherent electrophysiologic properties in elderly people without atrial fibrillation. [5][6][7][10][11][12][13][14][15][16][17] The percent maximum atrial fragmentation has been reported to reflect prolongation of the atrial electrogram, the presence of a conduction abnormality, or the occurrence of atrial fibrillation. 13) In this study, the percent maximum atrial fragmentation was greater in patients with inducible atrial fibrillation than in those without inducible atrial fibrillation, which is concordant with previous reports.…”

“…7,[10][11][12][13] 2) Right atrial effective refractory period: Right atrial effective refractory period was defined as "the longest S1-S2 interval that does not provoke A2 in the high right atrium". 10,[13][14][15] 3) Wavelength index: Wavelength index was defined as "the ratio of effective refractory period / maximum width of A2". 10,[13][14][15][16] …”

“…10,[13][14][15] 3) Wavelength index: Wavelength index was defined as "the ratio of effective refractory period / maximum width of A2". 10,[13][14][15][16] …”