Key result
Filtered unipolar electrograms showed significantly greater amplitude reduction than bipolar electrograms at low-voltage sites (<0.5 mV) and loss of S wave at sites of no pace capture after ablation.
Why the study?
Does filtered unipolar electrogram morphology improve the assessment of ablation lesion transmurality compared to bipolar electrograms in patients with atrial fibrillation?
Observational (n=6)
Does filtered unipolar electrogram morphology improve the assessment of ablation lesion transmurality compared to bipolar electrograms in patients with atrial fibrillation?
Filtered unipolar electrograms, specifically the disappearance of the S wave, may serve as a useful marker for assessing transmural lesion formation during pulmonary vein isolation.
Unipolar S-wave loss may mark transmural lesions in AF ablation; leaves open superiority over bipolar signals pending validation.
BACKGROUND: Although alteration of the amplitude and morphology of bipolar electrograms is used widely as a guide of the ablation effect, there is little information concerning unipolar electrograms. The amplitude and morphology of filtered bipolar (BP) and filtered unipolar (UP) electrograms were compared during pulmonary vein isolation in patients with atrial fibrillation. METHODS: BP (30-250 Hz) and UP (30-100 Hz) signals from the ablation catheter were recorded before and after each ablation point at the pulmonary vein antrum in 6 patients with atrial fibrillation. RESULTS: In the electrogram group with low-voltage amplitude in BP electrograms before ablation (<0.5 mV), the reduction in amplitude after ablation was significantly greater in the UP than in the BP electrograms, whereas the reduction was similar between the two recording methods in the electrogram group with high-voltage amplitude in BP electrograms (≥0.5 mV). Furthermore, the S wave in the UP electrograms disappeared at the sites of no pace capture after ablation, whereas no characteristic morphologic changes were observed in the BP electrograms. CONCLUSION: Filtered UP electrograms may be useful in assessing the effectiveness of lesion formation.
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Kogawa et al. (2015) conducted an observational in Atrial fibrillation (n=6). Filtered unipolar (UP) electrograms vs. Filtered bipolar (BP) electrograms was evaluated on Amplitude and morphology changes before and after ablation. Filtered unipolar electrograms showed significantly greater amplitude reduction than bipolar electrograms at low-voltage sites (<0.5 mV) and loss of S wave at sites of no pace capture after ablation.
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