Optimal cutoff value of bipolar low-voltage in electroanatomic voltage mapping during atrial fibrillation rhythm

Electroanatomic voltage mapping (EAVM) of the left atrium (LA) with multielectrodes is usually acquired during sinus rhythm (SR), and the feasibility of EAVM during atrial fibrillation (AF) rhythm is unclear.

We performed EAVM of LA during both SR and AF rhythm in 44 patients undergoing catheter ablation for AF and validated the optimal cutoff value of low-voltage area (LVA) during AF rhythm for detecting LVA defined as bipolar voltages ≤0.5 mV during SR.

In each session, mean 829 and 552 points were acquired by multielectrodes during SR and AF rhythm, respectively. Mean proportion of LVA was 4.9% among LA surface area of 276.2 cm² . Differences of LVA proportions between SR and AF rhythm were 5.8% (P < 0.001), 4.2% (P < 0.001), 2.7% (P < 0.001), 1.2% (P = 0.01), and -0.5% (P = 0.17) at the cutoff value of 0.4, 0.35, 0.3, 0.25, and 0.2 mV during AF rhythm, respectively. There was a good correlation between LVA proportions during SR and AF rhythm with cutoff value of 0.2 mV (R = 0.88, P < 0.001) and 37 patients (84.1%) had the discrepancy of LVA proportions within 3%. Furthermore, there was no significant difference between LVA proportions at each segment of LA. The discrepancy was relatively large in patients with large LA dimension and LVA during SR.

EAVM during AF rhythm was feasible and the optimal cutoff value of LVA was 0.2 mV for detecting LVA ≤ 0.5 mV during SR. However, the evidence is restricted to patients with relatively small LVA.