Tailoring the Ablative Strategy for Atrial Fibrillation: A State-of-the-Art Review

Figure 2

The trace shows the trigger of atrial fibrillation. It seems due to an extra systolic beat (), but the endocardial electrogram shows the following sequence: sinus beat (), extra systolic beat (), and blocked extra systolic beat (°). This latter is the effective trigger of atrial fibrillation (CS: coronary sinus; ABL: ablator; D: distal; P: proximal).