High-density epicardial mapping reveals that human long-lasting persistent atrial fibrillation is characterized by highly heterogeneous and unstable activation patterns rather than stable rotors.
OBJECTIVES: To characterize the nature of atrial fibrillation (AF) activation in human persistent AF (PerAF) using modern tools including activation, directionality analyses, complex-fractionated electrogram, and spectral information. BACKGROUND: The mechanism of PerAF in humans is uncertain. METHODS AND RESULTS: High-density epicardial mapping (128 electrodes/6.75 cm(2)) of the posterior LA wall (PLAW), LA and RA appendage (LAA, RAA), and RSPV-LA junction was performed in 18 patients with PerAF undergoing open heart surgery. Continuous 10 s recordings were analysed offline. Activation patterns were characterized into four subtypes (i) wavefronts (broad or multiple), (ii) rotational circuits (≥2 rotations of 360°), (iii) focal sources with centrifugal activation of the entire mapping area, or (iv) disorganized activity isolated chaotic activation(s) that propagate ≤3 bipoles or activation(s) that occur as isolated beats dissociated from the activation of adjacent bipole sites. Activation at a total of 36 regions were analysed (14 PLAW, 3 RSPV-LA, 12 LAA, and 7 RAA) creating a database of 2904 activation patterns. In the majority of maps, activation patterns were highly heterogeneous with multiple unstable activation patterns transitioning from one to another during each recording. A mean of 3.8 ± 1.6 activation subtypes was seen per map. The most common patterns seen were multiple wavefronts (56.2 ± 32%) and disorganized activity (24.2 ± 30.3%). Only 2 of 36 maps (5.5%) showed a single stable activation pattern throughout the 10-s period. These were stable planar wavefronts. Three transient rotational circuits were observed. Two of the transient circuits were located in the posterior left atrium, while the third was located on the anterior surface of the LAA. Focal activations accounted for 11.3 ± 14.2% of activations and were all short-lived (≤2 beats), with no site demonstrating sustained focal activity. CONCLUSION: Human long-lasting PerAF is characterized by heterogeneous and unstable patterns of activation including wavefronts, transient rotational circuits, and disorganized activity.
“These 'plaque array' studies have consistently revealed local activation to be highly dynamic and heterogeneous with stable re-entry circuits or indeed rotors uncommon. The plaque array, however, cannot see the whole picture so it seems to be a key step forward that it is now possible to record global activation from a limited set of intracardiac electrograms or body surface electrograms.”
Lee et al. (Thu,) studied this question.