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Periodic high-frequency electrical waves, rotor drift contribute to electrogram fractionation
Complex and transitioning electrical mechanisms in AF cited as major driver of fractionated electrograms.
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15th Annual Boston Atrial Fibrillation Symposium
Complex fractionated atrial electrograms, considered an ideal target site for ablation in patients with atrial fibrillation, are often driven by complex electrical activity that can quickly become disorganized and fractionated, according to a review of data presented at the 2010 Boston Atrial Fibrillation Symposium.
Jose Jalife, MD, professor of cardiology and internal medicine at the University of Michigan Medical School in Ann Arbor, suggested that high-frequency periodic electrical waves emanating from sources of AF in close proximity to the posterior left atrium may be associated with the highest fractionated activity in locations adjacent to the sources. Electrical impulses that travel in irregular patterns across the left atrium, which Jalife characterized as moving in rotor-like fashion, can become more disorganized and unpredictable as they travel further from the maximum dominant frequency where they originated.
“Complex fractionated atrial electrocardiograms ablation have become part of the mainstream, but I would submit that they are unfortunately much more complicated than previously thought,” Jalife said in his presentation. “Because these drifting rotors leave a footprint, we wanted to search for that footprint in human patients with AF.”
Jalife presented results from a study of 24 patients with drug-refractory paroxysmal AF and located the impulses using a spiral catheter. The researchers measured beat-to-beat changes, electrogram duration, number of spikes within a given electrogram and changes in cycling. They reported that impulse activity could become fractionated and disorganized as it traveled, but also that the electrogram duration and number of spikes increased progressively; the cycling progressively decreased with the transitions from organized to disorganized activity. The change from organized to disorganized activity was reported as significant.
“High frequency periodic electrical waves emerging from AF sources at or near the posterior left atrium undergo recurrent intermittent blockade and fragmentation at the periphery sources,” Jalife concluded. “In addition, drifting of the rotor that drives AF contributes to signal fractionation. Therefore, rotor drifting and fibrillatory conduction around AF sources are the underlying bases for fractionated electrograms whose cycle length is ≤120 ms.” – by Eric Raible
For more information:
- Jalife J. Presented at: 15th Annual Boston Atrial Fibrillation Symposium; Jan 14-16, 2010; Boston.