Left Atrial Remodeling Identification and Catheter Ablation Outcomes With 18F-Fluorodeoxyglucose Positron Emission Tomography in Persistent Atrial Fibrillation.

BACKGROUND

Left atrial structural remodeling contributes to the persistence of atrial fibrillation (AF) and influences the outcomes of catheter ablation (CA). We investigated the usefulness of 18F-fluorodeoxyglucose-positron emission tomography in detecting low atrial glucose uptake (LGU) as a potential marker of fibrosis and its predictive value for CA success in persistent AF.

METHODS

Thirty-six patients without diabetes with persistent AF scheduled for CA underwent nicotinic acid-stimulated 18F-fluorodeoxyglucose-positron emission tomography to assess global and segmental LGU before CA. LGU was compared with low voltage areas on electroanatomical mapping, left atrial volume index via echocardiography, and late gadolinium enhancement from cardiac magnetic resonance imaging as indicators of fibrosis. Patients were followed for up to 24 months post CA to assess AF recurrence.

RESULTS

Global LGU extent was 16.8% (7.6-42.6) and correlated with left atrial volume index (R2=0.20, P=0.039) and low voltage area during AF and right atrial pacing (R2=0.54 and R2=0.35 respectively, both P<0.001). Multivariable analysis showed that LGU significantly predicted moderate/severe low voltage area remodeling (P<0.001) with an area under the curve of 0.78 (95% CI, 0.58-0.97), independent of clinical and imaging parameters. AF recurred in 50% of patients. LGU >17%, but not late gadolinium enhancement, predicted AF recurrence (P=0.026; AUC, 0.67 [95% CI, 0.48-0.86]).

CONCLUSIONS

Nicotinic acid-enhanced 18F-fluorodeoxyglucose-positron emission tomography LGU extent reflects fibrosis by low voltage areas and predicts AF recurrence after CA in patients with persistent AF. This suggests that it could serve as a noninvasive tool for assessing atrial fibrosis and remodeling in atrial cardiomyopathy due to persistent AF.