Key result
Lack of bipolar voltage reversal despite bidirectional block predicts 100% atrial flutter recurrence.
Why the study?
To assess the role of subclinical conduction, observed via polarity reversal of local bipolar signals lateral to the ablation line, in predicting recurrence of CTI-dependent AFL despite bidirectional conduction block.
Does achieving reversal of local bipolar signals (absence of subclinical conduction) in addition to bidirectional block prevent recurrence of CTI dependent atrial flutter in patients undergoing catheter ablation?
Observational (n=73)
Does achieving reversal of local bipolar signals (absence of subclinical conduction) in addition to bidirectional block prevent recurrence of CTI dependent atrial flutter in patients undergoing catheter ablation?
Absolute Event Rate: 100% vs 27%
Achieving bidirectional conduction block alone is insufficient to prevent atrial flutter recurrence; ensuring reversal of local bipolar signals to eliminate subclinical conduction significantly reduces recurrence.
Bidirectional block without bipolar signal reversal may not prevent AFL recurrence; leaves open whether reversal should be a routine ablation endpoint.
BACKGROUND: Achieving bi-directional conduction block, as assessed by differential pacing and change in activation along tricuspid annulus (TA), across the cavo-tricuspid isthmus (CTI), is considered a satisfactory end point during catheter ablation of atrial flutter (AFL). AIM: To assess role of subclinical conduction by observing polarity reversal of local bipolar signals from RS to QR pattern lateral to the line of ablation, in predicting recurrence of CTI dependant AFL after ablation in patients with bidirectional conduction block. METHOD AND RESULTS: Of 683 patients undergoing ablation of CTI dependent AFL, 73 (10.6%) patients underwent redo flutter ablation and were evaluated further. The mean age was 60.8 years and 51% were males. Evidence of bidirectional block by differential pacing and change is activation along multipolar catheter and reversal of local bipolar signals from RS to QR pattern lateral to the line of ablation, during the 1st and subsequent procedure, were studied. 60% patients had confirmed bidirectional block of which 71% had lack of voltage reversal, at the end of 1st procedure. All patients with bidirectional block with lack of reversal of bipolar signals, after the first procedure had recurrence of AFL whereas only 3/11 (27%) people with bidirectional block and with absence of subclinical conduction had recurrence of AFL. CONCLUSION: Achieving bidirectional conduction block is not sufficient to prevent recurrence of AFL after CTI ablation. Reversal of local bipolar signals, from RS to QR pattern along with achieving bidirectional conduction delay would reduce recurrence of AFL, post ablation.
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Nubila et al. (2023) conducted an observational in Cavo-tricuspid isthmus dependent atrial flutter (n=73). Lack of voltage reversal of local bipolar signals (subclinical conduction) vs. Absence of subclinical conduction (reversal of bipolar signals) was evaluated on Recurrence of atrial flutter. Lack of voltage reversal of local bipolar signals despite bidirectional block resulted in 100% recurrence of atrial flutter, compared to 27% recurrence in patients with signal reversal.
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