BACKGROUND: The posterior left atrium (LA) is involved in the initiation and maintenance of atrial fibrillation (AF). OBJECTIVE: The purpose of this study was to compare conduction patterns on the posterior LA in patients with mitral regurgitation (MR), with and without AF. METHODS: Epicardial mapping of the posterior LA was performed in 23 patients undergoing cardiac surgery. Patients were included in one of three groups: Group A-patients in sinus rhythm with normal left ventricular function undergoing coronary artery bypass grafting, Group B-patients in sinus rhythm with MR undergoing mitral valve surgery, or Group C-patients in persistent AF with MR undergoing mitral valve surgery. Conduction patterns, regional conduction velocity, conduction heterogeneity, conduction anisotropy, and complex fractionated atrial electrograms (CFAEs) were assessed. RESULTS: LA diameter was greater in patients in Groups C (57 +/- 4mm) and B (54 +/- 6mm) than in Group A (39 +/- 7 mm, P <0.01). Patients in Group C had a greater number of lines of conduction delay than Groups A and B (2.0 +/- 0.8 vs 1 +/- 0 and 1 +/- 0, P <0.05). The extent of conduction delay and conduction heterogeneity was greater in Group C than in Group B, which was greater than in Group A (P <0.05). The percentage of CFAEs that remained stable during AF was 61% +/- 17%. There was a significant correlation between CFAEs during AF and regions of slow conduction during pacing (R = 0.36, P <0.001). CONCLUSION: Patients with MR, LA enlargement, and AF have more extensive regions of conduction slowing in the posterior LA. Anatomically constant lines of conduction delay in this region lead to circuitous wavefront propagation. During persistent AF, fractionated electrograms in the posterior LA are distributed to regions demonstrating slow conduction, and the majority remain stable over time.
BACKGROUND: The posterior left atrium (LA) is involved in the initiation and maintenance of atrial fibrillation (AF). OBJECTIVE: The purpose of this study was to compare conduction patterns on the posterior LA in patients with mitral regurgitation (MR), with and without AF. METHODS: Epicardial mapping of the posterior LA was performed in 23 patients undergoing cardiac surgery. Patients were included in one of three groups: Group A-patients in sinus rhythm with normal left ventricular function undergoing coronary artery bypass grafting, Group B-patients in sinus rhythm with MR undergoing mitral valve surgery, or Group C-patients in persistent AF with MR undergoing mitral valve surgery. Conduction patterns, regional conduction velocity, conduction heterogeneity, conduction anisotropy, and complex fractionated atrial electrograms (CFAEs) were assessed. RESULTS: LA diameter was greater in patients in Groups C (57 +/- 4mm) and B (54 +/- 6mm) than in Group A (39 +/- 7 mm, P <0.01). Patients in Group C had a greater number of lines of conduction delay than Groups A and B (2.0 +/- 0.8 vs 1 +/- 0 and 1 +/- 0, P <0.05). The extent of conduction delay and conduction heterogeneity was greater in Group C than in Group B, which was greater than in Group A (P <0.05). The percentage of CFAEs that remained stable during AF was 61% +/- 17%. There was a significant correlation between CFAEs during AF and regions of slow conduction during pacing (R = 0.36, P <0.001). CONCLUSION:Patients with MR, LA enlargement, and AF have more extensive regions of conduction slowing in the posterior LA. Anatomically constant lines of conduction delay in this region lead to circuitous wavefront propagation. During persistent AF, fractionated electrograms in the posterior LA are distributed to regions demonstrating slow conduction, and the majority remain stable over time.
Authors: Thomas J van Brakel; Thomas van der Krieken; Sjoerd W Westra; Jeroen A van der Laak; Joep L Smeets; Henry A van Swieten Journal: J Interv Card Electrophysiol Date: 2013-09-12 Impact factor: 1.900
Authors: Karuna Chilukuri; Daniel Scherr; Darshan Dalal; Alan Cheng; David Spragg; Saman Nazarian; Bernadette D Barcelon; Joseph E Marine; Hugh Calkins; Charles A Henrikson Journal: J Interv Card Electrophysiol Date: 2011-05-26 Impact factor: 1.900
Authors: Saverio Iacopino; Gaetano Paparella; Lucio Capulzini; Erwin Ströker; Stefan Beckers; Thiago Guimarães Osório; Varnavas Varnavas; Juan Sieira; Juan Pablo Abugattas; Riccardo Maj; Francesca Salghetti; Vincent Umbrain; Muryo Terasawa; Pedro Brugada; Carlo de Asmundis; Gian Battista Chierchia Journal: J Interv Card Electrophysiol Date: 2019-04-27 Impact factor: 1.900