Key Points
- To investigate the transversal conduction properties across the crista terminalis during rapid pacing after cavotricuspid isthmus ablation in patients with typical atrial flutter.
- Assessed 22 patients (mean age 61±7 years) with typical atrial flutter (mean cycle length 234±23 ms) following bidirectional cavotricuspid isthmus block achieved via radiofrequency catheter ablation.
- Delivered decremental pacing trains (from 600 ms down to 2-to-1 local capture) at the lateral wall and the posterior wall or coronary sinus ostium while recording at least 5 bipolar electrograms along the crista terminalis.
- Posterior wall or coronary sinus pacing produced complete transversal conduction block across the crista terminalis in all 22 patients at a cycle length of 334±136 ms, which was fixed in 4 patients.
- Lateral wall pacing produced complete block at a significantly shorter pacing cycle length (281±125 ms; P<0.01), which was fixed in 2 patients and absent in 3 patients.
Structured PICO
Does the pacing site (posterior vs lateral wall) affect the rate-dependent transversal conduction block at the crista terminalis in patients with typical atrial flutter?
PPopulation22 patients with typical atrial flutter (AFL), mean age 61+/-7 years, AFL cycle length 234+/-23 ms.
IInterventionDecremental pacing trains from 600 ms to 2-to-1 local capture at the lateral wall (LW) and posterior wall (PW) or coronary sinus ostium (CSO) after radiofrequency catheter ablation of the cavotricuspid isthmus.
CComparatorPacing from the posterior wall (PW) or coronary sinus ostium (CSO) compared to pacing from the lateral wall (LW).
OOutcomeComplete transversal conduction block all along the crista terminalis (CT).surrogate
Rate-dependent transversal conduction block at the crista terminalis occurs at longer cycle lengths with posterior wall pacing than lateral wall pacing, which may explain the counterclockwise rotation of typical atrial flutter.