Temporal changes in atrial refractoriness following DC cardioversion of persistent atrial fibrillation in man

Aims Studies have demonstrated shortening of the atrial effective refractory period (ERP) after episodes of atrial. fibrillation (AF). This is termed atrial remodelling. It is unclear whether restoration of SIR after persistent AF in patients with a clinical substrate results in reversal of this shortening and whether this is maintained long term. Methods and results The ERP was determined at mid-lateral right atrial, wall (MLRA) and right atrial. appendage (RAA) at 600 ms and 400 ms drive cycle lengths and at basic sinus cycle length in 81 patients with persistent AF immediately, 24 h and 2 weeks following external DC cardioversion. All atrially active drugs were stopped for at least 5 half lives. (1) Prolongation of the ERP was observed at both atrial. sites and all cycle lengths up to 24 h post cardioversion (p < 0.0001). (2) However, between 24 h and 2 weeks a subsequent shortening occurred in the ERP returning it to near post cardioversion levels. (3) The ERP was significantly longer at 24 h post cardioversion in patients who remained in SIR for 2 weeks or Longer compared with those who reverted to AF. Conclusion Prolongation of the atrial ERP occurred following restoration of SIR in persistent AF patients but was not maintained and displayed a biphasic pattern such that by 2 weeks the ERP had returned to baseline values. Despite this finding, a longer ERP at 24 h post cardioversion was associated with maintenance of SIR in the medium-term. (C) 2004 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.