Frequency Gradient Within Coronary Sinus Predicts the Long-Term Outcome of Persistent Atrial Fibrillation Catheter Ablation

Abstract

Background: The coronary sinus (CS), as a junction of the atria, contributes to atrial fibrillation (AF) by developing unstable reentry, and isolating the atria by ablation at the CS could terminate AF. The present study evaluated whether AF activities at the CS in a subset of patients contributed to AF maintenance and predicted clinical outcome of ablation.

Methods and results: We studied 122 consecutive patients who had a first-time radiofrequency ablation for persistent AF. Bipolar electrograms were obtained from multiple regions of the left atrium by a Lasso mapping catheter before ablation. Pulmonary vein isolation terminated AF in 12 patients (9.8%). Sequential stepwise ablation was conducted in pulmonary vein isolation nontermination patients and succeeded in 22 patients (18%). In the stepwise termination group, AF frequency in the proximal CS (CSp) was significantly higher (10.2±2.1 Hz versus 8.3±1.8 Hz, P<0.001), and the ratio of distal CS (CSd) to proximal CS (CSd/CSp ratio, 56.6%±10.11% versus 70.7%±9.8%, P<0.001) was significantly lower than that in the nontermination group. The stepwise logistic regression analysis indicated that the CSd/CSp ratio was an independent predictor with an odds ratio of 1.131 (95%CI 1.053-1.214; P=0.001). With a cutoff of 67%, the patients with lower CSd/CSp ratios had significantly better index and long-term outcomes than those with higher ratios during a follow-up of 46±18 months.

Conclusions: Rapid repetitive activities in the musculature of the proximal CS may contribute to maintenance of AF after pulmonary vein isolation alone in persistent AF. A cutoff at 67%, of the CSd/CSp frequency ratio might be an indicator to stratify the subset of patients who might benefit from CS ablation.

Keywords: ablation; atrial fibrillation; coronary sinus; pulmonary vein isolation; radiofrequency.

Figure 1

Typical CARTO 3D map images and tracings from a patient with sequential stepwise ablation in anteroposterior (AP) and posteroanterior (PA) views. Lasso mapping was implemented to obtain bipolar electrograms from pulmonary vein (PV) ostia, left atrial appendage (LAA), the roof of left atrium, as well as posterior and anterior parts of left atrium. The models of left atria and PVs were created by Lasso catheter in AP (left) and PA (right) positions. LA indicates left atrium; LIPV, left inferior PV; LSPV, left superior PV; RIPV, right inferior PV; RSPV, right superior PV.

Figure 2

Typical CARTO 3D map images and tracings from a patient with stepwise ablation in left anterior oblique and anteroposterior (AP) views. Lasso mapping was implemented to obtain bipolar electrograms from the proximal and distal coronary sinus (CS), the superior vena cava (SVC), as well as the crista terminal of the right atrium. The models of right and left atria were created by a Lasso catheter in left anterior oblique 45° (left) and AP (right) positions. CSd and CSp respectively indicate distal and proximal coronary sinus.

Figure 3

A, The models of the coronary sinus (CS) and left atrium were created by Lasso catheters in the left anterior oblique 45° (left) and left lateral positions. B, The difference of electrical activity within the CS. C, Persistent atrial fibrillation converts to SR after CS potential was ablated. CSp indicates proximal CS; LA, left atrium; SR, sinus rhythm.

Figure 4

Scatterplot showing the (A) frequency in the proximal coronary sinus (CSp) and (C) the distal coronary sinus (CSd) ratio (CSd/CSp ratio) before catheter ablation, Horizontal line indicates optimal diagnostic cutoff value to predict termination of atrial fibrillation. Receiver‐operator characteristics (ROC) curve analysis with (B) frequency in the CSp and (D) the ratio of the frequency of CSd/CSp. Arrows shows optimal cutoff point for sensitivity and specificity. CS indicates coronary sinus; PV indicates pulmonary vein.

Figure 5

Kaplan‐Meier survival curves plotted to assess clinical outcomes of ablation for persistent atrial fibrillation according to distal frequency/proximal frequency cutoff values. CSd indicates distal coronary sinus; CSp, proximal coronary sinus.