High-rate pacing-induced atrial fibrillation effectively reveals properties of spontaneously occurring paroxysmal atrial fibrillation in humans

Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Europace (Impact Factor: 3.67). 06/2012; 14(11). DOI: 10.1093/europace/eus180
Source: PubMed


AimsResearch on paroxysmal atrial fibrillation (AF) assumes that fibrillation induced by rapid pacing adequately reproduces spontaneously occurring paroxysmal AF in humans. We aimed to compare the spectral properties of spontaneous vs. induced AF episodes in paroxysmal AF patients.Methods and resultsEighty-five paroxysmal AF patients arriving in sinus rhythm to the electrophysiology laboratory were evaluated prior to ablation. Atrial fibrillation was induced by rapid pacing from the pulmonary vein-left atrial junctions (PV-LAJ), the coronary sinus (CS), or the high right atrium (HRA). Simultaneous recordings were obtained using multipolar catheters. Off-line power spectral analysis of 5 s bipolar electrograms was used to determine dominant frequency (DF) at recording sites with regularity index >0.2. Sixty-eight episodes were analysed for DF. Comparisons were made between spontaneous (n 23) and induced (n 45) AF episodes at each recording site. No significant differences were observed between spontaneous and induced AF episodes in HRA (5.18 ± 0.69 vs. 5.06 ± 0.91 Hz; P 0.64), CS (5.27 ± 0.69 vs. 5.36 ± 0.76 Hz; P 0.69), or LA (5.72 ± 0.88 vs. 5.64 ± 0.75 Hz; P 0.7) regardless of pacing site. Consistent with these results, paired analysis in seven patients with both spontaneous and induced AF episodes, showed no regional DFs differences. Moreover, a left-to-right DF gradient was also present in both spontaneous (PV-LAJ 5.71 ± 0.81 vs. HRA 5.18 ± 0.69 Hz; P 0.005) and induced (PV-LAJ 5.62 ± 0.72 vs. HRA 5.07 ± 0.91 Hz; P 0.002) AF episodes, with no differences between them (P not specific).Conclusion
In patients with paroxysmal AF, high-rate pacing-induced AF adequately mimics spontaneously initiated AF, regardless of induction site. © 2012 Published on behalf of the European Society of Cardiology.

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    ABSTRACT: Background: Triggers from thoracic veins have been implicated not only in the initiation, but also in the perpetuation of paroxysmal atrial fibrillation (PAF). To investigate their role we studied the distribution and stability of dominant frequencies (DFs) during PAF and the response to isolation of the triggering pulmonary vein (PV). Methods and results: Triggering structures inducing PAF were identified during isoproterenol challenge in 26 patients (15 males, 55 ± 8.5 years). During sustained PAF, sequential recordings were made with a decapolar circular mapping catheter from each PV and the left atrial posterior wall (LAPW), together with coronary sinus (CS) and right atrium (RA) recordings. DF was determined using fast Fourier transformation. Recordings were repeated after ≥15 minutes of PAF. Radiofrequency ablation was directed first at the triggering PVs. PAF initiated from the PVs in 24 patients and from RA in two. There was a significant frequency gradient from the triggering structure to the PVs, CS, LAPW, and RA (P < 0.0001). During the second recording, DF decreased at all sites (P < 0.02), but the frequency gradient remained unchanged. Despite isolation of the triggering PV, PAF continued in 53% of patients, although DF measured in the CS was lower. AF termination occurred with contralateral PV isolation in half of the remaining patients and further AF slowing was noted in the rest. Conclusions: Triggering structures harbor the fastest activity during sustained PAF pointing to their leading role in arrhythmia perpetuation. However, nontriggering PVs also seem to contribute to PAF maintenance.
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