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Fibrillatory Activity (fibrillatory + activity)
Selected AbstractsClustering of RR Intervals Predicts Effective Electrical Cardioversion for Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 9 2004MAARTEN P. VAN DEN BERG M.D. Introduction: Atrial fibrillation (AF) is characterized by an irregularly irregular ("random") heart beat. However, controversy exists whether the ventricular rhythm in AF is truly random. We investigated randomness by constructing three-dimensional RR interval plots (3D plots), allowing identification of "clustering" of RR intervals. It was hypothesized that electrical cardioversion (ECV) would be more effective in AF patients with clustering, because clustering might reflect a higher degree of organization of atrial fibrillatory activity. Methods and Results: The study group consisted of 66 patients (44 men and 22 women; mean age 68 ± 11 years,) who were referred for ECV because of persistent AF. Twenty-four-hour Holter recordings were used to construct 3D plots by plotting each RR interval (x axis) against the previous RR interval (y axis) and the number of occurrences of each of these x,y combinations (z axis). A clustering index was calculated as the percentage of beats within the peaks in the 3D plot. Based on the 3D plots, clustering of RR intervals was present in 31 (47%) of the 66 patients. ECV was effective in restoring sinus rhythm in 29 (94%) of these 31 patients, whereas sinus rhythm was restored in only 25 (71%) of the remaining 35 patients without clustering (P = 0.020). The clustering index ranged from <2% in the 12 patients with failed ECV to >8% in the 32 patients with sinus rhythm at the end of the study (4 weeks after the ECV); the clustering index in the 22 patients with a relapse of AF after effective ECV was intermediate (P = 0.034 and P = 0.042, respectively). Conclusion: This study indicates that ECV is more effective in restoring sinus rhythm in AF patients with clustering compared to patients in whom no clustering is apparent on 3D plots. In addition, the degree of clustering appears to be predictive of the overall outcome of ECV; the higher the degree of clustering, the higher the likelihood of sinus rhythm at follow-up. [source] Characterization of Paroxysmal and Persistent Atrial Fibrillation in the Human Left Atrium During Initiation and Sustained EpisodesJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2002GJIN NDREPEPA M.D. Characterization of AF in the LA.Introduction: Atrial fibrillation (AF) in the left atrium (LA) is poorly defined in terms of regional differences in the degree of organization, characteristics of paroxysmal and persistent variants, and electrophysiologic events that develop at the onset of episodes. Methods and Results: The study population consisted of 21 patients (15 men and 6 women; mean age 58 ± 9.4 years) with paroxysmal (10 patients) or persistent (11 patients) AF. Mapping of the LA during sustained episodes and the onset of AF was performed with a 64-electrode basket catheter. At the onset of AF, repetitive beats starting with atrial premature complexes and ending with generation of the earliest fibrillatory activity were defined as intermediary rhythm. Patients with paroxysmal AF had longer AF cycle lengths and more pronounced regional differences than patients with persistent AF. In total, AF cycle lengths in the LA in patients with persistent AF were 20% shorter than in patients with paroxysmal AF. Initiation of AF was preceded by an intermediary rhythm of 5.5 ± 2.5 cycles (6.3 ± 2.7 cycles in paroxysmal AF vs 4.2 ± 1.0 cycles in persistent AF; P = 0.026). At the onset of AF, the earliest generators of fibrillatory activity were located more frequently in the posterior wall of the LA. Conclusion: AF in the LA displays substantial regional differences in terms of AF cycle lengths and degree of organization. Patients with persistent AF have shorter cycle lengths and a higher degree of disorganized activity than patients with paroxysmal AF. Intermediary rhythms play an important role in initiation of AF via activation of generator regions in the LA. [source] Electrophysiological Differences of the Spontaneous Onset of Paroxysmal and Persistent Atrial FibrillationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2007STEFAN WEBER M.D. Background: Information about the spatiotemporal organization of atrial activity at the onset of atrial fibrillation (AF) is still limited. Methods: AF mapping was performed in 30 patients with AF (mean age 53 ± 9 years, 26 males) by deploying a noncontact mapping balloon in the left atrium (LA). Twenty-four patients had paroxysmal AF and six patients had persistent AF. Three types of AF episodes were analyzed: nonsustained AF (lasting , 30 seconds), sustained AF (lasting > 30 seconds, with spontaneous conversion or requiring internal cardioversion and subsequent stable sinus rhythm), and persistent AF episodes (stable sinus rhythm lasting , 1 minute after cardioversion). Results: A total of 101 spontaneous AF onset episodes were analyzed. Analysis of AF onset showed that there was a progressive shortening of the initial cycle lengths from nonsustained episodes to sustained episodes and to persistent AF episodes. There was an earlier and more rapid reduction in the cycle lengths from persistent episodes to sustained episodes and to nonsustained episodes of AF (P < 0.05 for persistent vs sustained and for sustained vs nonsustained episodes). The development of multiwavelet activity and disorganization of conduction occurred earlier in persistent and sustained episodes than in nonsustained AF episodes. LA size was greater in patients with persistent AF episodes compared with patients with sustained or nonsustained AF episodes. Conclusions: Electrophysiological events that develop at the onset of AF seem to be different in different types of AF. A more rapid degeneration into the fibrillatory activity was observed in persistent and sustained AF than in nonsustained AF episodes. [source] | ||||||||||