ORGANIZED ACTIVATION DURING ATRIAL-FIBRILLATION IN MAN - ENDOCARDIAL AND ELECTROCARDIOGRAPHIC MANIFESTATIONS

Atrial Fibrillation Organization. Introduction: Atrial fibrillation is not entirely random, but little is known about the spatiotemporal end ocardial organization and its surface ECG manifestations. Methods and Results: In 16 patients with atrial fibrillation (chronic, n = 14), en docardial mapping of the trabeculated, the posteroseptal smooth right atrium, and the coronary sinus was performed using multipolar catheter s, The surface ECG was analyzed by determining ''fibrillation wave'' ( F wave) amplitude, rate, and polarity. During 50 minutes of atrial fib rillation, an organized activation was present 72% +/- 32% of the anal yzed time on the trabeculated, 19% +/- 15% on the smooth right atrium (P < 0.01), and 51% +/- 33% along the coronary sinus (P < 0.05). The d irection of organized activation was craniocaudal in 72% +/- 16%, caud ocranial in 10% +/- 9% (P < 0.01), and indeterminable in 18% +/- 11%. The mean surface F wave amplitude in lead V-1 was 0.128 +/- 0.06 mV du ring 28 seconds of atrial fibrillation with a craniocaudal direction o f activation and 0.065 +/- 0.02 mV during a disorganized activation (P < 0.01). A stable relation between surface F waves and organized trab eculated right atrial activation was observed, and the mean F wave cyc le length (190 +/- 27 msec) was highly comparable to the simultaneousl y measured endocardial cycle length (191 +/- 27 msec, correlation coef ficient 0.97). F wave polarity in V-1 was positive in 12 of 14 patient s during craniocaudal and negative in 11 of 14 patients during caudocr anial right atrial free-wall activation. Conclusion: An organized acti vation during atrial fibrillation with a predominant craniocaudal dire ction on the trabeculated right atrium is frequently present and influ ences the appearance of ''coarse'' or ''fine'' atrial fibrillation as well as F wave polarity on the surface ECG.