Title

Relationship between the spectral characteristics of atrial fibrillation and atrial tachycardias that occur after catheter ablation of atrial fibrillation

Document Type

Article

Department

Internal Medicine (East Africa)

Abstract

We read with interest the study by Yoshida et al 1 in the January 2009 issue of Heart Rhythm. The authors demonstrated that there was often a spectral component in the baseline atrial fibrillation (AF) periodogram that matched the frequency of atrial tachycardia (AT) that occurred acutely during ablation (group I patients). In contrast, this finding was seen less often in AT occurring late after ablation in a separate group of patients (group II patients).

The study used atrial electrograms from both coronary sinus (CS) electrodes and lead V 1 (after QRS subtraction) for analysis, but only the periodogram from the CS electrodes showed convincingly the more frequent presence of a spectral component matching the frequency of AT in group I patients. In the Discussion, the authors suggest that although lead V 1 is more indicative of global atrial depolarization than is a single CS electrode, it may be more representative of the right than the left atrium, quoting work by Dibs el al. 2 This observation was previously reported by Hsu et al. 3Because cavotricuspid isthmus–dependent atrial flutter accounted for 40% of the macroreentrant AT in group I patients, it would be interesting to see whether a matching spectral component was more readily seen in the periodogram from lead V 1 in this group of patients.

The ablation approach used in the study included antral pulmonary vein isolation followed by ablation of complex fractionated atrial electrograms in the CS and the left and right atria. We wonder if the authors encountered any problems with signal analysis because ablation or isolation of the CS would impair the signals recorded by the CS electrode.

Although group I and group II patients had similar degrees of reduction of dominant frequency of AF signals after ablation, it is interesting that none of the group II patients converted to AT despite undergoing a similar ablation strategy. This finding suggests a difference in AF substrate burden between the two groups that probably is reflected by the significantly longer duration of AF in group II patients.

Publication

Heart Rhythm