Electrocardiographic Imaging as Preoperative Tool in Persistent and Long-Standing Persistent Atrial Fibrillation: A Prospective Observational Study.

Objectives: Surgical ablation for treating atrial fibrillation (AF) is currently performed mostly without preoperative electrophysiological imaging. This study aimed to investigate the use of non-invasive surface mapping as a preoperative tool to explore potential mechanisms and patterns involved in the electrophysiology of persistent and long-standing persistent AF.

Methods: This prospective, observational study included cardiac surgery candidates without previous ablation. Bi-atrial epicardial activation sequences were obtained with electrocardiographic imaging and analysed in an independent core lab. Statistical analyses included hierarchical clustering, which quantified 3 clusters based on the number of drivers to identify specific characteristics.

Results: All 51 patients [14 (27%) persistent; 37 (73%) long-standing persistent; AF, duration 42 months (interquartile range 14-120)] had bi-atrial electrophysiological abnormalities. Most rotors were harbored in the upper half of the right atrium, involved in almost all patients (50/51, 98%), followed by the pulmonary vein areas and left-atrial backwall (48/51, 94%). Longer AF duration showed no association towards fewer rotor and focal activity (r = -0.08, P = 0.42; r = -0.06, P = 0.56, respectively). A significant correlation existed between larger left atrial (LA) size and fewer rotors (r = -0.33, P < 0.001), but not focal activity (r = 0.01, P = 0.92). The clusters differed in AF duration and LA size, and in their number of rotor and focal activities (P = 0.005, P < 0.001, respectively).

Conclusions: The underlying electrophysiological mechanism was identified in all patients and consistently showed bi-atrial involvement irrespective of AF duration, LA size, or concomitant heart disease. In larger left atria and longer AF duration, the observed lower number of rotors might be related to atrial tissue fibrosis and lower amplitudes. The results demonstrate the potential role of preoperative mapping to improve procedural planning and our understanding of patients' electrophysiology.

Clinical registration: ClicalTrials.gov NCT06803615.