Frequency analysis of atrial fibrillation from the specific ECG leads V7-V9: A lower DF in lead V9 is a marker of potential atrial remodeling.

INTRODUCTION: High dominant frequency (DF) sites during atrial fibrillation (AF) play an important role in the perpetuation of AF. We investigated the relationship between the DFs from intracardiac electrograms (iEGM) and the surface electrocardiogram (ECG) during AF, and the relationship between the surface ECG DF and atrial remodeling.

METHODS: In 48 patients (57±11 years, 47 males, 20 paroxysmal), the V1-6 precordial leads and specific V7-9 ECG leads were recorded for 8s for an off-line analysis before AF ablation. The QRS-T complex was canceled by a template subtraction algorithm using the CEPAS™ system (Cuoretech Pty Ltd, Sydney, Australia). The iEGM DF maps, reconstructed using the Ensite NavX (St. Jude Medical, Inc., St. Paul, MN, USA) system, were simultaneously created for the right atrium and left atrium (LA) during AF.

RESULTS: The DF in leads V8 and V9 correlated well with the DF in the LA floor (R=0.55, p<0.01; R=0.68, p<0.01, respectively), and that in V1 with the right inferior pulmonary vein (R=0.45, p=0.01). Persistent AF patients had a significantly lower DF in lead V9 (5.7±1.0Hz vs. 6.7±1.5Hz, p=0.02) than paroxysmal AF patients.

CONCLUSIONS: A frequency analysis from lead V9 reflects the LA electrical activity.