Influence of left atrium anatomical contact area in persistent atrial fibrillation-relationship between low-voltage area and fractionated electrogram.

BACKGROUND

Atrial low-voltage areas are suggested to be related to maintenance of atrial fibrillation (AF). The influence of the left atrium (LA) contact area (CoA) has not been investigated.

METHODS AND RESULTS

Twenty-two persistent AF patients underwent high-density mapping during AF and sinus rhythm (SR). Three representative CoA regions in the LA (ascending aorta: anterior wall; descending aorta: left inferior pulmonary vein [LIPV]; and vertebrae: posterior wall) were identified. Electrogram analysis of both high dominant frequency (high-DF; >8 Hz) and complex fractionated atrial electrogram (con-CFAE; <50 ms) regions during SR was done. The anatomical relationship between CoA and both the very low-voltage areas (vLVA; <0.2 mV) and high-frequency sources was determined. Forty-seven vLVA (194.4 cm(2)) and 60 CoA (337.0 cm(2)) were documented, and 32 vLVA directly overlapped CoA. The vLVA were preferentially found in the anterior (45%) and posterior (13%) walls of the LA, and in the LIPV (13%), and corresponded to CoA sites. The mean voltage during SR at high-DF sites was significantly lower than that at con-CFAE sites (0.62 vs.1.54 mV; P<0.0001). Seventy-two percent of high-DF sites overlapped CoA, while 54% of con-CFAE did. Furthermore, 44% of high-DF surface area directly overlapped CoA, while only 19% of con-CFAE did.

CONCLUSIONS

Very low-voltage regions had a strong association with CoA. Sites with CoA had a higher incidence of fractionated electrograms both during SR and AF.