Article

Functional characterization of atrial electrograms in sinus rhythm delineates sites of parasympathetic innervation in patients with paroxysmal atrial fibrillation

University of California, Los Angeles, Los Ángeles, California, United States
Journal of the American College of Cardiology (Impact Factor: 15.34). 11/2007; 50(14):1324-31. DOI: 10.1016/j.jacc.2007.03.069
Source: PubMed

ABSTRACT This study sought to characterize left atrial (LA) sinus rhythm electrogram (EGM) patterns and their relationship to parasympathetic responses during atrial fibrillation (AF) ablation.
The mechanistic basis of fractionated LA EGMs in patients with paroxysmal AF is not well understood.
We analyzed 1,662 LA ablation sites from 30 patients who underwent catheter ablation for paroxysmal AF. Pre-ablation EGM characteristics (number of deflections, amplitude, and duration) were measured in sinus rhythm. Parasympathetic responses during radiofrequency application (increase of atrial-His interval by > or =10 ms or decrease of sinus rate by > or =20%) were assessed at all sites. We also prospectively studied the effect of adenosine, a pharmacological agent mimicking acetylcholine signaling in myocytes, on LA EGMs. Finally, we performed mathematical simulations of atrial tissue to delineate possible mechanisms of fractionated EGMs in sinus rhythm.
A specific pattern of pre-ablation sinus rhythm EGM (deflections > or =4, amplitude > or =0.7 mV, and duration > or =40 ms) was strongly associated with parasympathetic responses (sensitivity 72%, specificity 91%). The sites associated with these responses were found to be located mainly in the posterior wall of the LA. Adenosine administration and mathematical simulation of the effect of acetylcholine were able to reproduce a similar EGM pattern.
Parasympathetic activation during AF ablation is associated with the presence of pre-ablation high-amplitude fractionated EGMs in sinus rhythm. Local acetylcholine release could potentially explain this phenomenon.

0 Followers
 · 
104 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The purpose of this study is to explore the left atrium (LA) electrophysiologic abnormalities in atrial fibrillation (AF) patients detected during sinus rhythm and to determine the relationship between the type of AF and the electrophysiologic substrate in the LA. Eighty patients with AF (30 paroxysmal AF, 22 persistent AF, and 28 long-standing AF) and 20 age- and sex-matched patients with left-sided accessory pathway were prospectively studied. High-density three-dimensional electroanatomic mapping was performed during sinus rhythm in LA, which was divided into six segments for regional analysis. Mean bipolar voltage, low voltage zone (LVZ) distribution, LA activation time, and electrogram complexity were assessed. The LA mean voltage was 3.67 ± 0.68 mV in no AF group, 2.16 ± 0.63 mV in the paroxysmal, 1.81 ± 0.36 mV in the persistent, and 1.48 ± 0.34 mV in the long-standing AF patients (P < 0.001). The total LA activation time was 75.3 ± 5.4 ms in no AF, 89.7 ± 12.3 ms in paroxysmal AF, 104.9 ± 6.1 ms in persistent AF, and 115.6 ± 12.1 ms in the long-standing AF patients, respectively (P < 0.001). With the progression of AF, there was a higher incidence of LVZ detection and increased prevalence of complex electrograms with 95 % of complex electrograms in areas with the bipolar voltage ≤ 1.3 mV in persistent and long-standing AF patients. Patients with AF have abnormal electrophysiologic substrate in sinus rhythm characterized by lower mean bipolar voltage, more prevalent complex electrograms, and longer LA activation time. This substrate progresses parallel to progression of AF type.
    Journal of Interventional Cardiac Electrophysiology 10/2013; 39(1). DOI:10.1007/s10840-013-9838-y · 1.55 Impact Factor
  • Source
    Circulation Arrhythmia and Electrophysiology 12/2014; 7(6):1230-6. DOI:10.1161/CIRCEP.114.002201 · 5.42 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Spectral analysis of the left atrium can identify high dominant frequency (DF) sites, which might play a role in the perpetuation of atrial fibrillation (AF). Furthermore, the role of the cardiac autonomic nervous system (CANS) in the genesis of AF has been demonstrated. The relationship between CANS and the high-DF sites (AF nest) was the aim of the investigation. Methods and Results: In 12 dogs, high frequency stimulation was applied to locate 4 major left atrial (LA) ganglionated plexi (GPs). An Ensite Array and a mapping catheter were delivered into the left atrium for electroanatomical mapping. During sinus rhythm, spectral analysis was performed on the bipolar electrograms in the left atrium before and after epicardial GP ablation. The majority of AF nests were close to the GPs (52±18% of total AF nests). After GP ablation, the mean LA DF values decreased from 54±7Hz to 49±4Hz (P=0.023), and DF values of the AF nest decreased from 93±2Hz to 87±4Hz (P=0.001). Most of the previous AF nest sites close to the GPs disappeared (85±23%). The surface area of the AF nest decreased from 9±5cm(2) to 3±2cm(2) (P=0.001). Conclusions: Catheter ablation of the GP decreased the DF values, AF nest areas and diminished the number of AF nests; particularly those close to the GPs, indicating that the CANS might play an important role in the mechanism of the AF nest.
    Circulation Journal 02/2014; 78(4). DOI:10.1253/circj.CJ-13-1053 · 3.69 Impact Factor

Full-text (2 Sources)

Download
23 Downloads
Available from
May 16, 2014