• P wave signal averaged ECG;
  • permanent atrial fibrillation;
  • chemoreflexsensitivity;
  • paroxysmal atrial fibrillation

Background: Paroxysmal atrial fibrillation (PAF) transits to permanent atrial fibrillation (PEAF). The current study was to determine whether a P wave-triggered P wave signal averaged electrocardiogram (P-SAECG) and chemoreflexsensitivity (CHRS) are useful to predict a conversion to PEAF in patients with PAF.

Methods: The filtered P wave duration (FPD) and the root mean square voltage of the last 20 ms of the P wave (RMS 20) were measured by P-SAECG. The ratio between the difference of RR intervals in the ECG and venous pO2 before and after 5-minutes oxygen inhalation is measured (ms/mmHg) for the determination of CHRS.

Results: A total of 180 patients with PAF were enrolled and followed for a mean of 22.5 months. PEAF occurred in 38 patients (21%) and these patients had a significantly larger left atrial size (43.2 ± 4.9 vs. 41.0 ± 5.4 mm, P = 0.021), a significantly longer FPD (158.8 ± 18.2 vs. 136.7 ± 16.6 ms, P < 0.0001), and a significantly lower CHRS (1.96 ± 0.99 vs. 2.44 ± 1.19 ms/mmHg, P = 0.024) than patients with PAF. Patients with PEAF tended to have a lower RMS 20 (2.38 ± 0.65 vs. 2.75 ± 1.18 μV, P = 0.067) than patients with PAF. The χ2 test showed that the combination of FPD ≥ 145 ms, RMS 20 ≤3.0 μV, left atrial size ≥ 41 mm, and CHRS ≤2.0 ms/mmHg had the best predictive power for PEAF. Patients who fulfilled these criteria had a 12-fold increased risk for a conversion from PAF to PEAF.

Conclusions: Our results show that a P-SAECG, an analysis of CHRS, and left atrial enlargement are clinical predictors of a progression from PAF to PEAF.