Identification of the Substrate of Atrial Vulnerability in Patients With Idiopathic Atrial Fibrillation

Abstract

Patients with idiopathic AF showed increased dispersion of refractoriness, which may be the substrate for the observed enhanced inducibility and spontaneous occurrence of AF.

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

“…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.…”

Atrial electrophysiologic abnormalities in patients with wolff‐parkinson‐white syndrome but without paroxysmal atrial fibrillation

“…[7][8][9][10][11][12][13] The %MAF and WLI have been reported to reflect the presence of conduction abnormalities 8 and the minimum length of the reentrant circuit at that site, 10 respectively. These parameters have also been reported to predict the occur- Values are reported as the mean ± SD (range) or number of patients (%).…”

Efeitos da estimulação com corrente elétrica contínua pulsátil sobre as propriedades eletrofisiológicas atriais: estudo experimental da fibrilação atrial em cães

“…Definitions -a) Atrial fibrillation: irregular cardiac rhythm in the absence of ordered atrial electrical activity (no P wave), which is replaced by irregular waves in the baseline; b) effective atrial refractory period: the shortest S1-S2 interval, in which S2 is not followed by atrial activation 5 ; overall effective atrial refractory period is the mean of the durations obtained in the ST, RAb, and LA regions; c) atrial refractoriness dispersion: defined by the coefficient of variation of the effective atrial refractory period as the ratio between the standard deviation of the mean and the mean of the refractory periods multiplied by 100 in each cycle of stimulation 6 ; d) times of intra-atrial and interatrial conduction: time required for activation of the RAb and LA from ST stimulation, measured between the spike of stimulation (S) and the corresponding local bipolar electrograms (A1); time of atrial conduction of the atrial extrastimulus is the interval measured between the spike of stimulation corresponding to the early impulse (S2) and the respective atrial electrogram (A2) 5,7 ; e) atrial anatomic remodeling: histologic modifications observed in cells and cell structures (myofibrils and mitochondria) and in the interstitial medium caused by atrial stimulation; f) atrial vulnerability: induction of atrial fibrillation after rapid atrial stimulation with a cycle of 100 ms performed in 3 consecutive attempts. The time of duration of induced atrial fibrillation corresponded to the greatest episode documented after the 3 periods of atrial stimulation at 600 ppm and not to the summation of the duration of short episodes of arrhythmia after each stimulation phase.…”