AIMS: The aim of this study was to determine the mechanisms of atrial fibrillation (AF) in patients with left ventricular systolic dysfunction (LVSD). METHODS AND RESULTS: Dominant frequency (DF) spatiotemporal stability was studied in 15 patients with persistent AF (PEAF) and LVSD (Group I), 15 with PEAF without LVSD (Group II), and 10 with paroxysmal AF (PAAF) without LVSD (Group III). Dominant frequencies were analysed at 536 sites at baseline (DF1) and 26 +/- 12 min later (DF2). A DF1-DF2 difference of <or=0.5 Hz was found in 77, 70, and 48% of sites in Groups I, II, and III (P < 0.001). Maximal DF1 and DF2 were recorded at the same site in 12/15, 11/15, and 0/10 patients in Groups I, II, and III, respectively (P < 0.01). Gradient differences: Group I, DFs were higher at left atrium appendage (LAA) than at anterior (A) LA (ALA), pulmonary vein-left atrial junction (PV-LAJ), and posterior (P) LA (PLA) (7.4 +/- 1.1 vs. 6.6 +/- 1 vs. 6.8 +/- 0.8 vs. 6.8 +/- 0.7 Hz, P < 0.05); Group II, no differences; Group III, DF was higher at PV-LAJ than at LAA, AL, and PLA (6 +/- 1.2 vs. 5.3 +/- 1.1 vs. 5.2 +/- 0.9 vs. 5.4 +/- 1.1 Hz, P < 0.05). CONCLUSION: Dominant frequency stability supports stable arrhythmia sources as the mechanism of PEAF with (without) LVSD, but not of PAAF.
AIMS: The aim of this study was to determine the mechanisms of atrial fibrillation (AF) in patients with left ventricular systolic dysfunction (LVSD). METHODS AND RESULTS: Dominant frequency (DF) spatiotemporal stability was studied in 15 patients with persistent AF (PEAF) and LVSD (Group I), 15 with PEAF without LVSD (Group II), and 10 with paroxysmal AF (PAAF) without LVSD (Group III). Dominant frequencies were analysed at 536 sites at baseline (DF1) and 26 +/- 12 min later (DF2). A DF1-DF2 difference of <or=0.5 Hz was found in 77, 70, and 48% of sites in Groups I, II, and III (P < 0.001). Maximal DF1 and DF2 were recorded at the same site in 12/15, 11/15, and 0/10 patients in Groups I, II, and III, respectively (P < 0.01). Gradient differences: Group I, DFs were higher at left atrium appendage (LAA) than at anterior (A) LA (ALA), pulmonary vein-left atrial junction (PV-LAJ), and posterior (P) LA (PLA) (7.4 +/- 1.1 vs. 6.6 +/- 1 vs. 6.8 +/- 0.8 vs. 6.8 +/- 0.7 Hz, P < 0.05); Group II, no differences; Group III, DF was higher at PV-LAJ than at LAA, AL, and PLA (6 +/- 1.2 vs. 5.3 +/- 1.1 vs. 5.2 +/- 0.9 vs. 5.4 +/- 1.1 Hz, P < 0.05). CONCLUSION: Dominant frequency stability supports stable arrhythmia sources as the mechanism of PEAF with (without) LVSD, but not of PAAF.