• atrial fibrillation;
  • pulmonary vein isolation;
  • P wave;
  • P-wave signal averaged electrocardiogram

Introduction: We hypothesize that successful pulmonary vein (PV) isolation can shorten the P-wave duration in patients with atrial fibrillation (AF).

Methods and Results: We recorded magnified surface electrocardiogram (ECG) and P-wave signal-averaged ECG using 12 electrode leads before and after 31 PV isolation procedures in 27 patients with AF. The patients were followed for 16 ± 4 months. Repeat ablation studies documented failed PV isolation in seven patients with AF recurrences. At baseline, the maximal P-wave duration in patients without AF recurrence (161 ± 7 msec) was slightly shorter than that in patients with AF recurrence (168 ± 10 msec, P < 0.05). After ablation, patients without recurrence showed a significant reduction of P-wave duration from 161 ± 7 msec to 151 ± 8 msec (P < 0.0001). In contrast, no change of P-wave duration was noted in patients with recurrences. These findings were confirmed with signal averaged ECG of the P-waves. Three-dimensional (3-D) computer simulation using an atrial cell model showed that elimination of the muscle sleeves inside the PV resulted in a shortening of the P-wave duration and change of the terminal portion of the P-wave morphology.

Conclusions: A significant shortening of P-wave duration by P-wave signal-averaged ECG can be used as an indicator for successful PV isolation. These findings suggest that activation of the PV muscle sleeves may be an important component of the terminal portion of the P-wave on surface ECG.