Recurrence quantification analysis of complex-fractionated electrograms differentiates active and passive sites during atrial fibrillation.

OBJECTIVES: To differentiate electrograms representing sites of active atrial fibrillation (AF) drivers from passive ones. BACKGROUND: Ablation of complex-fractionated atrial electrograms (CFAEs) is controversial due to difficulty in distinguishing CFAEs representing sites of active AF drivers from passive mechanisms. We hypothesized that active CFAE sites exhibit repetitive wavefront directionality, thereby inscribing an electrogram conformation (Egm-C) that is more recurrent compared with passive CFAE sites; and that can be differentiated from passive CFAEs using nonlinear recurrence quantification analysis (RQA). METHODS: We developed multiple computer models of active CFAE mechanisms (ie, rotors) and passive CFAE mechanisms (ie, wavebreak, slow conduction, and double potentials). CFAE signals were converted into discrete time-series representing Egm-C. The RQA algorithm was used to compare signals derived from active CFAE sites to those from passive CFAEs sites. The RQA algorithm was then applied to human CFAE signals collected during AF ablation (n = 17 patients). RESULTS: RQA was performed in silico on simulated bipolar CFAEs within active (n = 45) and passive (n = 60) areas. Recurrence of Egm-C was significantly higher in active compared with passive CFAE sites (31.8% ± 19.6% vs 0.3% ± 0.5%, respectively, P < .0001) despite no difference in mean cycle length (CL). Similarly, for human AF (n = 39 signals), Egm-C recurrence was higher in active vs passive CFAE areas despite similar CLs (%recurrence 13.6% ± 15.5% vs 0.1% ± 0.3%, P < .002; mean CL 102.5 ± 14.3 vs 106.6 ± 14.4, P = NS). CONCLUSION: Active CFAEs critical to AF maintenance exhibit higher Egm-C recurrence and can be differentiated from passive bystander CFAE sites using RQA.

Lone atrial fibrillation is associated with pectus excavatum.

BACKGROUND: Pectus excavatum is a skeletal abnormality that may have cardiac manifestations. OBJECTIVE: To determine whether pectus excavatum is associated with lone atrial fibrillation (AF). METHODS: The pectus severity index (PSI) is the ratio of the lateral diameter of the chest to the distance between the sternum and the spine on computed tomography scan. A normal PSI is ≤2.5 whereas patients with severe pectus excavatum have a PSI >3.25. We calculated the PSI of 220 consecutive patients with AF who underwent radiofrequency catheter ablation from September 2008 to 2012 and compared this to the PSI of 225 controls without a history of AF undergoing chest computed tomography. RESULTS: Mean PSI was higher in patients with lone AF (2.72 ± 0.07) compared to patients with nonlone AF (2.25 ± 0.03) or controls (2.26 ± 0.03) (P < .001). The likelihood of mild, moderate, or severe pectus excavatum was higher in patients with lone AF compared to patients with nonlone AF and controls (P < .001). Patients with lone AF were more than 5 times as likely to have severe pectus excavatum compared to patients with nonlone AF or controls (P < .001) even after adjustment for potential confounders. CONCLUSIONS: Nearly two-thirds of the patients with lone AF have at least mild pectus excavatum and 17% have severe pectus, which is significantly higher than in patients with nonlone AF or controls. This association suggests a potential genetic or mechanical abnormality may be common to the 2 disorders. Our study may provide insight into the pathogenesis of lone AF.

Elimination of focal atrial fibrillation with a single radiofrequency ablation: use of a basket catheter in a pulmonary vein for computerized activation sequence mapping.

A focal source for atrial fibrillation (AF) may be found in the first few centimeters of the pulmonary veins. Radiofrequency (RF) ablation may be directed at this source using activation mapping, but if the responsible atrial extrasystoles are infrequent or difficult to map, elimination of the source may require complete electrical isolation of the vein with multiple RF lesions. A new three-dimensional mapping system using a 64-pole basket catheter has been developed recently. We report the use of this system for ablation of focal AF in two patients. Mapping identified foci in the left and right superior pulmonary veins. Each focus was eliminated with a single RF ablation.