Real-time dominant frequency mapping and ablation of dominant frequency sites in atrial fibrillation with left-to-right frequency gradients predicts long-term maintenance of sinus rhythm

Abstract

Background: Spectral analysis identifies localized sites of high-frequency activity during atrial fibrillation (AF).

Objective: This study sought to determine the effectiveness of using real-time dominant frequency (DF) mapping for radiofrequency ablation of maximal DF (DFmax) sites and elimination of left-to-right frequency gradients in the long-term maintenance of sinus rhythm (SR) in AF patients.

Methods: DF mapping was performed in 50 patients during ongoing AF (32 paroxysmal, 18 persistent), acquiring a mean of 117 +/- 38 points. Ablation was performed targeting DFmax sites, followed by circumferential pulmonary vein isolation.

Results: Ablation significantly reduced DFs (Hz) in the LA (7.9 +/- 1.4 vs. 5.7 +/- 1.3, P <.001), coronary sinus (CS) (5.7 +/- 1.1 vs. 5.3 +/- 1.2, P = .006), and RA (6.3 +/- 1.4 vs. 5.4 +/- 1.3, P <.001) abolishing baseline left-to-right atrial DF gradient (1.7 +/- 1.7 vs. 0.2 +/- 0.9; P <.001). Only a significant reduction in DFs in all chambers with a loss of the left-to-right atrial gradient after ablation was associated with a higher probability of long-term SR maintenance in both paroxysmal and persistent AF patients. After a mean follow-up of 9.3 +/- 5.4 months, 88% of paroxysmal and 56% of persistent AF patients were free of AF (P = .02). Ablation of DFmax sites was associated with a higher probability of remaining both free of arrhythmias (78% vs. 20%; P = .001) and free of AF (88% vs. 30%; P <.001).

Conclusion: Radiofrequency ablation leading to elimination of LA-to-RA frequency gradients predicts long-term SR maintenance in AF patients.

Figure 1

A, Real-time atrial DF map (posterior view; CARTO system) in a paroxysmal AF patient. Purple, primary DFmax site (red arrow) on right intermediate PV (RIPV). Red dots, circumferential ablation line. B, bipolar recording (top) of primary DFmax site and its power spectrum (bottom) prior to ablation. C, surface ECG leads and intracardiac lasso catheter electrograms within RIPV; ablation catheter in the encircled area, CS and HRA catheter during isolation of right-sided PVs. Catheters recording outside the encircled area (CS, HRA) show conversion to SR (star) whereas the lasso catheter inside RIPV demonstrates ongoing AF.

Figure 2

Spatial distribution of DFmax sites in paroxysmal and persistent AF patients grouped in four regions: PV-PLAW, LA, RA, and CS.

Figure 3

Regional DFmax following ablation in paroxysmal AF patients in relation to long-term freedom from AF. A. DFmax in LA, RA and CS and LA-to-RA gradient were all significantly reduced in AF free (right) compared with recurrent AF patients (left). B. Right, LA-to-RA DF gradient disappeared following ablation. Left, in patients with recurrent AF, maximal regional DFs were significantly reduced in LA only, with no significant change in LA-to-RA gradient.

Figure 4

Regional DFmax following ablation in persistent AF patients in relation to long-term freedom from AF. A. Right, AF-free patients had a significant reduction in maximal regional DF in both LA and RA. Left, in patients with recurrent AF, DF was reduced in LA and CS only. B. LA-to-RA DF gradient was abolished in AF-free patients (right) but not in patients with recurrent AF (left). The presence of a LA-to-RA gradient at baseline was predictive of freedom from AF.

Figure 5

DF maps in a persistent AF patient; LA posterior view. A, Prior to ablation. B, Prior to redo procedure. Purple, primary DF site on the LA posterior wall. Note close correlation between both maps regarding primary DF site location (posterior LA wall) and maximal DF values at primary DF site.

Figure 6

DF maps in paroxysmal AF patient. A, prior to ablation. A DFmax site was identified in LIPV. Significantly lower frequencies are recorded in the other chambers, confirming the LA-to-RA DF gradient at baseline. B, immediately after DFmax site ablation and CPVI. Note significant reductions in DFmax in all chambers, with shift in DFmax to LAA.

Figure 7

DF maps in a persistent AF patient. A, prior to ablation. A DFmax site was identified in the right superior PV (red arrow). B, Immediately after DFmax site ablation and CPVI. Significant reduction in DF is observed in all chambers, with a shift in DFmax to the RAA. No electrical signals are recorded inside the encircled veins.