Non-Pulmonary Vein Triggers of Atrial Fibrillation Are Likely to Arise from Low-Voltage Areas in the Left Atrium

Abstract

The pathophysiology of non-pulmonary vein (PV) triggers of atrial fibrillation (AF) is unclear. We hypothesized that left atrial non-PV (LANPV) triggers are associated with atrial tissue degeneration. This study analyzed 431 patients that underwent catheter ablation (mean age 62 yrs, 303 men, 255 paroxysmal AF [pAF] patients). Clinical and electrophysiological characteristics of non-PV trigger were analyzed. Fifty non-PV triggers in 40 patients (9.3%) were documented; LANPV triggers were the most prevalent (n = 19, 38%). LANPV triggers were correlated with non-paroxysmal AF (non-pAF) (OR 3.31, p = 0.04) whereas right atrial non-PV (RANPV) triggers (n = 14) and SVC triggers (n = 17) were not. The voltage at the LANPV sites during SR was 0.3 ± 0.16 mV (p < 0.001 vs. control site). Low-voltage areas (LVAs) in the LA were significantly greater in non-pAF compared to pAF (14.2% vs. 5.8%, p < 0.01). RANPV trigger sites had preserved voltage (0.74 ± 0.48 mV). Long-term outcomes of patients with non-PV triggers treated with tailored targeting strategies were not significantly inferior to those without non-PV triggers. In conclusion, non-PV triggers arise from the LA with degeneration, which may have an important role in AF persistence. A trigger-oriented, patient-tailored ablation strategy considering LA voltage map may be feasible and effective in persistent/recurrent AF.

Figure 1

A representative case with a non-PV trigger from the LA septum. (a,b) The intracardiac electrograms and electroanatomical mapping indicate that the non-PV trigger arises from an LVA. (c) The fluoroscopy shows the catheter position. Red asterisks indicate the trigger site of AF. CS: coronary sinus, TA: tricuspid annulus.

Figure 2

A representative case with a non-PV trigger from the left atrial posterior free wall. (a) Delayed and anisotropic conduction following an ectopic trigger is observed at AF initiation. (b) Red asterisks in the fluoroscopies indicate AF trigger site. HRA: high right atrium, LAPFW: left atrial posterior free wall, LSPV: left superior pulmonary vein, SVC: superior vena cava, RV: right ventricle.

Figure 3

Voltage of non-PV trigger sites during sinus rhythm. (a) The voltage of LANPV sites was lower than that of control sites (LA posterior wall). (b) The voltage of RANPV sites was preserved compared to that of control sites (crista terminalis). CT: crista terminalis.

Figure 4

The relationship between LVAs and the AF type. (a) LVA-positive case with persistent AF; the percentage of LVA was 24.6%. Two asterisks indicate AF trigger (non-PV) sites in the LVA. (b) LVA-negative case of pAF; the percentage of LVA was <10%. (c) Mean percentage of LVA in the pAF and non-pAF groups. (d) Prevalence of LVA ≥ 10% in these two groups.

Figure 5

Kaplan-Meier curves showing AF/AT recurrence-free survival after the last ablation. (a) AF/AT-free survival rate in patients with non-PV triggers and without. (b) AF/AT-free survival rate in patients with LA non-PV triggers, SVC/RA non-PV triggers and in the control group respectively. (c) AF/AT-free survival rate in patients with pAF and non-pAF. (d) AF/AT-free survival rate in patients with or without non-PV triggers in pAF and non-pAF separately.