Consistency of complex fractionated atrial electrograms during atrial fibrillation.

BACKGROUND Temporal variation in complex fractionated atrial
electrograms (CFAEs) exists during atrial fibrillation (AF).
OBJECTIVE This study sought to quantify the variation in CFAEs
using a fractionation interval (FI) algorithm and to define the
shortest optimal recording duration required to consistently characterize
the magnitude of the fractionation.
METHODS Twenty-seven patients undergoing AF mapping in the
left atrium were studied. The FI and frequency analysis were
performed at each mapped site for recording durations of 1 to 8
seconds. The magnitude of the fractionation was quantified by the
FI algorithm, which calculated the mean interval between multiple,
discrete deflections during AF. The results from each duration
were statistically compared with the maximal-duration recording,
as a standard. The FI values were compared with the dominant
frequency values obtained from the associated frequency spectra.
RESULTS The FIs obtained from recording durations between 5
and 8 seconds had a smaller variation in the FI (P .05) and, for
those sites with a FI 50 ms, the fractionation was typically
continuous. The fast-Fourier Transform spectra obtained from the
CFAE sites with recording durations of 5 seconds harbored higher
dominant frequency values than those with shorter recording
durations (8.1 2.5 Hz vs. 6.8 0.98 Hz, P .05). The CFAE
sites with continuous fractionation were located within the pulmonary
veins and their ostia in 77% of patients with paroxysmal
AF, and in only 29% of patients with nonparoxysmal AF (P .05).
CONCLUSION The assessment of fractionated electrograms requires
a recording duration of 5 seconds at each site to obtain
a consistent fractionation. Sites with the shortest FIs consistently
identified sites with the fastest electrogram activity throughout
the entire left atrium and pulmonary veins.