Illustration of different atrial activation associated with different body surface atrial waveform morphology.

(A) Different stimulated points (circle) and tip of re-entry across the surface of the atria (i), atrial action potentials (ii) and their corresponding body surface atrial-waves at different excitation rates (iii): top 3Hz; bottom 5Hz. (B) Snapshot of atrial activation at control conditions at a fast rate, (i) and its corresponding ECG exhibiting distinct P-wave in lead V1 (ii). (C) Snapshot of atrial activation when the tip of the re-entry is located in the SAN (i), and its corresponding atrial waves of lead V1 (ii). (D) Snapshot of atrial activation with the focal ectopic activity located in the right atrial appendage (RAA) (i) and the corresponding atrial waves of lead V1 (ii). A red sign represents a positive polarity in the atrial-wave (magenta/shaded area), the blue sign is a negative polarity and a purple sign represents a biphasic atrial-wave (magenta/shaded area).