Background: Left atrial (LA) endocardial voltage characteristics assessed during atrial fibrillation (AF) have not been previously compared in different AF types. This study was aimed at investigating the LA voltages and volumes in patients with paroxysmal and persistent AF.
Methods: LA electroanatomic voltage maps acquired during AF were compared between consecutive patients without major structural heart disease undergoing first catheter ablation for paroxysmal AF (n = 100) or persistent AF (n = 100). The groups were comparable in baseline clinical characteristics.
Results: Patients with persistent AF presented with lower median LA voltage (median 0.41, interquartile range [IQR] 0.31-0.51 mV versus median 0.99, IQR 0.47-1.56 mV; P < 0.001), and maximum LA voltage (4.07 +/- 1.76 vs 6.42 +/- 2.16 mV; P < 0.001). They also had a higher proportion of the LA points exhibiting voltage <0.2 mV (30 +/- 20 vs 12 +/- 11%; P < 0.001) and voltage 0.2-1.0 mV (55 +/- 15 vs 42 +/- 19%; P < 0.001). They further displayed higher LA volume/body surface area (75 +/- 16 vs 58 +/- 13 mL/m(2); P < 0.001). In the multivariate regression model, both LA voltage (P < 10(-9)) and LA volume (P < 10(-5)) were significant determinants of AF type.
Conclusion: Patients with persistent AF had significantly lower LA voltage compared with patients with paroxysmal AF even after adjustment for differences in indexed LA volume. LA voltage represents an independent covariate of clinical manifestation of AF.