title: Long-term outcome after cardioversion of atrial fibrillation: prediction of recurrence with P wave signal averaged ECG and chemoreflexsensitivity.
abstract: OBJECTIVE
  The recurrence of atrial fibrillation after cardioversion was a general problem in medical practice.
  
  
  METHODS
  We wanted to test the hypothesis that the recurrence of atrial fibrillation could be predicted by measurements of P wave triggered P wave signal averaged ECG and chemoreflexsensitivity (CHRS) in 118 consecutive patients one day after successful electrical cardioversion. We measured the filtered P wave duration (FPD) and the root mean square voltage of the last 20 ms of the P wave (RMS 20) with P wave triggered P wave signal averaged ECG. The CHRS was calculated of a ratio between the difference of RR intervals in ECG and venous pO2 before and after 5-min oxygen inhalation. The pathologic CHRS was predefined as a CHRS below 3.0 ms/mm Hg.
  
  
  RESULTS
  A recurrence of atrial fibrillation was observed in 57 patients (48%) during a 9.3-month follow-up. The left atrial size (41.9+/-4.0 vs. 39.3+/-3.1 mm, P<0.0003) was larger, the FPD (139.6+/-16.0 vs. 118.2+/-14.1 ms, P<0.0001) was longer, the RMS 20 (2.57+/-0.77 vs. 3.90+/-0.99 muV, P<0.0001) and the CHRS (2.66+/-1.18 vs. 4.01+/-1.66 ms/mm Hg, P<0.0001) were lower in patients with recurrence of atrial fibrillation. A cut-off point was defined with FPD > or =126 ms and RMS 20 < or =3.1 muV and could predict atrial fibrillation with a specificity of 77%, a sensitivity of 72%, a positive value of 75%, a negative predictive value of 75% and an accuracy of 75%. Patients with FPD > or =126 ms and RMS 20 < or =3.1 muV had nearly a 7-fold increase risk for recurrence of atrial fibrillation.
  
  
  CONCLUSIONS
  The recurrence of atrial fibrillation after cardioversion could be detected by P wave signal averaged ECG and an analysis of CHRS. These methods seem to be appropriate to show a delayed atrial conduction and a neurovegetative imbalance which might be possible trigger mechanisms of reinitiating of atrial fibrillation.
authors.affiliation: Department of Cardiology, West-German Heart Centre, University of Duisburg-Essen, Germany. marco.budeus@medizin.uni-essen.de
authors.forename: Marco
authors.initials: M
authors.lastname: Budeus
authors.forename: Heinrich
authors.initials: H
authors.lastname: Wieneke
authors.forename: Stefan
authors.initials: S
authors.lastname: Sack
authors.forename: Raimund
authors.initials: R
authors.lastname: Erbel
authors.forename: Christian
authors.initials: C
authors.lastname: Perings
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D001341:Autonomic Nervous System / Q000503:physiopathology*; D002628:Chemoreceptor Cells / Q000503:physiopathology*; D004554:Electric Countershock; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D016896:Treatment Outcome