Abstract 11127: Electrophysiologic Characteristics of the Left Atrial Myocardium Specific for the Genesis of Complex Fractionated Atrial Electrograms During Atrial Fibrillation
Background: Complex fractionated atrial electrograms (CFAE) region has been suggested to contribute to the maintenance of atrial fibrillation (AF). However, electrophysiologic characteristics of left atrial myocardium responsible for the genesis of CFAE has not been clarified.
Objectives: The purpose of this study was to define the electrophysiologic characteristics of the left atrial myocardium specific for the genesis of CFAE.
Methods: Endocardial mapping of left atrium was performed in 19 patients with AF. The electrogram amplitude and width, and conduction velocity were measured during sinus rhythm and premature atrial contraction (PAC) with long- (L-PAC) and short-coupling intervals (S-PAC) which did not initiate AF and very-short-coupling interval (VS-PAC) which initiated AF. These parameters were compared between CFAE and non-CFAE regions.
Results: The coupling intervals of L-, S- and VS-PAC were 291±87, 206±47 and 175±33 msec. The amplitudes in CFAE region were significantly higher than those in non-CFAE region during sinus rhythm, L-, S- and VS-PAC (2.0±1.3 vs. 0.5±0.6 mV, p<0.01; 1.3±1.2 vs. 0.3±0.3 mV, p<0.001; 0.7±0.7 vs. 0.2±0.2 mV, p<0.001). The amplitudes decreased following shortening of coupling interval both in CFAE and non-CFAE regions. The electrogram width in CFAE region were not different from those in non-CFAE region during sinus rhythm and L-PAC (65.9±9.2 vs. 63.8±12.6 ms, p=NS; 79.6±17.2 vs. 69.6±12.4 ms, p=NS), however those during S- and VS-PAC in CFAE were significantly wider than those in non-CFAE region (95.9±18.8 vs. 81.6±17.1 ms p<0.05; 103.5±86.4 vs. 86.4±21.0 mV, p<0.003). Conduction velocity during sinus rhythm, L-, S- and VS-PAC in CFAE were significantly slower than those in the non-CFAE region (1.3±0.4 vs. 2.1±1.0 M/sec, p=0.001; 1.3±0.4 vs. 2.3±1.2 M/sec, p=0.005; 1.1±0.5 vs. 2.0±1.1 M/sec, p=0.002; and 0.9±0.5 vs. 1.8±0.8 M/sec, p<0.001).
Conclusions: The CFAE was generated in the high amplitude atrial myocardium with slow and heterogeneous conduction properties which were pronounced associated with premature activation. Thus, fibrosis may not be a sole underlying mechanism for the genesis of CFAE, but anisotropic conduction produced in high amplitude region may also contribute to the genesis of CFAE.
- © 2011 by American Heart Association, Inc.