Heterogeneity of the Frequency Domain Patterns in Persistent Atrial Fibrillation

Background Persistent atrial fibrillation (AF) has remained a challenging clinical problem. The mechanisms of persistent AF are still subject to debate. Both a single mother-rotor with fibrillatory conduction and multiple meandering spiral waves have been proposed to explain persistent AF. Previous frequency domain studies have reported the presence of dominant frequency (DF) gradient (a marker of single mother-rotor) in paroxysmal, but not persistent AF. Methods and Results We performed temporally-dense high-resolution frequency domain analysis of 10-40 minutes segments of intracardiac signals recorded in 24 patients undergoing ablation of persistent AF. We observed two predominant patterns. The expected signature of the mother-rotor mechanism was observed in 38% of the patients. The frequency pattern in 54% consisted of two or more distinct frequency peaks with no obvious gradient, which is consistent with multiple separate primary spiral waves in electrophysiologically heterogeneous areas of atria. The average measured number of rotors per case was 1.71 ± 0.32, which provides a lower limit on the actual number of rotors. The single-zone pattern was exclusively seen in patients who were on a membrane-active antiarrhythmic medication at the time of ablation (P < 0.005). Conclusions AF is a heterogeneous disorder. High-frequency resolution analysis is a useful tool to detect the underlying mechanisms of AF and to classify it into patterns consistent with a single mother-rotor vs. multiple meandering wavelets.