Novel Assessment of Temporal Variation in Fractionated Electrograms Using Histogram Analysis of Local Fractionation Interval in Patients With Persistent Atrial Fibrillation
ABSTRACT Background- The characteristics of atrial electrograms associated with atrial fibrillation (AF) termination are controversial. We investigated the electrogram characteristics that indicate procedural AF termination during continuous complex fractionated electrogram ablation. Methods and Results- Fifty-two consecutive patients with persistent AF (47 men; aged 54±9 years), who underwent electrogram-based catheter ablation in the left atrium and coronary sinus after pulmonary vein isolation, were enrolled. The intracardiac bipolar atrial electrogram recordings were characterized by (1) fractionation interval (FI) analysis (>6 seconds), (2) kurtosis (shape of the FI histogram), and (3) skewness (asymmetry of the FI histogram). Sites showing complex, fractionated electrograms (mean FI ≤60 ms) were targeted, and AF was terminated in 20 patients (38%) after the pulmonary vein isolation. The conventional complex fractionated electrogram sites (mean ≤120 ms) in patients with AF termination exhibited higher median kurtosis (2.69 [interquartile range, 2.03-3.46] versus 2.35 [interquartile range, 1.79-2.48]; P=0.024) and higher complex fractionated electrogram-mean interval (102.7±19.8 versus 87.7±15.0; P=0.008) than patients without AF termination. Furthermore, AF termination sites had higher median kurtosis than targeted sites without AF termination (5.13 [interquartile range, 3.51-6.47] versus 4.18 [interquartile range, 2.91-5.34]; P<0.01) in patients with procedural termination. In addition, patients with AF termination had a higher sinus rhythm maintenance rate after a single procedure than patients without AF termination (log-rank test, P=0.007). Conclusions- A kurtosis analysis using the FI histogram may be a useful tool in identifying the critical substrate for persistent AF and potential responders to catheter ablation.
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ABSTRACT: BACKGROUND: Successful termination of atrial fibrillation (AF) during catheter ablation (CA) is associated with arrhythmia-free follow-up. Pre-ablation factors such as mean AF cycle length (AFCL) predict the likelihood of AF termination during ablation but recurring patterns and AFCL stability have not been evaluated. AIM: To investigate novel predictors of acute and postoperative ablation outcomes from intra-cardiac electrograms (EGM):  recurring AFCL patterns;  localization index (LI) of the instantaneous fibrillatory rate (IFR) distribution. METHODS AND RESULTS: 62 patients with AF (32 paroxysmal AF; 45 men; age 57±10 years), referred for CA were enrolled. 1 minute EGM was recorded from coronary sinus (CS; 5 bipoles) and right atrial appendage (HRA; 2 bipoles). Atrial activations were detected automatically to derive AFCL and IFR [inverse of AFCL] time-series. Recurring AFCL patterns were quantified using recurrence plot indices (RPI): percentage determinism (PD); entropy of determinism (ER); maximum diagonal length (LMAX). AFCL stability was determined by LI. CA outcome predictivity of individual indices was assessed. Terminating AF (T-AF) had higher RPI (p<0.05 in CS7-8) and LI than non-terminating (p<0.005 in CS3-4, p<0.05 in CS5-6, CS7-8, HRA). Arrhythmia-free patients after 3-month follow-up had higher RPI and LI (all p<0.05 in CS7-8). All indices except PD predicted T-AF in CS7-8 (AUC≥0.71, p<0.05; OR ≥4.50). Median AFCL and LI predicted T-AF in HRAD (AUC≥0.75, p<0.05; OR≥7.76). RPI and LI predicted 3-month follow-up (AUC≥0.68, p<0.05; OR ≥4.17) in CS7-8. CONCLUSIONS: AFCL recurrence and stability indices could be used in selecting patients more likely to benefit from CA.Heart rhythm: the official journal of the Heart Rhythm Society 06/2013; 10(9). DOI:10.1016/j.hrthm.2013.06.007 · 4.92 Impact Factor
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ABSTRACT: -Identification of critical atrial substrates in nonparoxysmal atrial fibrillation (AF) patients failing to respond to pulmonary vein isolation (PVI) is important. This study investigated the signal characteristics, substrate nature, and ablation results of rotors during AF. -In total 53 patients (age=55±8), 31 with persistent AF and 22 with long-lasting AF, underwent PVI and substrate modification of complex fractionated atrial electrograms (CFAEs). Small-radius-reentrant rotors were identified from signal analyses of the dominant frequency (DF), fractionation interval (FI) and nonlinear analyses (newly developed, beat-to-beat nonlinear measurement of the repetitiveness of the electrogram morphology over 6 seconds). In 15% of the patients, activation maps demonstrated occurrences of rotor-like small-radius reentrant circuits (N=9, 1.1 per patient, cycle length=110±21 ms; diameter=11±6 mm) with fibrillation occurring outside these areas. Rotors were identified by conventional point-by-point mapping and signal analyses, and were subsequently eradicated by catheter ablation in these patients. Persistent AF for <1 year, a smaller left atrial size, substrates with higher mean voltages and shorter total activation durations predicted a higher incidence of rotors (all p <0.05). In the multivariable model, areas of reentrant circuits exhibited a higher DF, kurtosis, and higher degree of a beat-to-beat electrogram similarity than areas without or outside the rotors (all p <0.05). -Rotors-like reentry with fibrillatory conduction were found in a limited number of patients with nonparoxysmal AF after PVI. Those areas were characterized by rapid repetitive activity with a high degree of electrogram similarity.Circulation Arrhythmia and Electrophysiology 08/2013; 6(5). DOI:10.1161/CIRCEP.113.000318 · 5.42 Impact Factor