[The high-resolution analysis of the P wave recorded via the esophagus: a new diagnostic approach in patients with paroxysmal atrial fibrillation].

BACKGROUND

P-wave signal averaged ECG has recently been proposed in the evaluation of patients with Paroxysmal Atrial Fibrillation (PAF). The aim of this study was to verify the utility of this method in the characterisation of these patients utilizing a transoesophageal signal.

METHODS

The study population consisted of two groups of subjects: Group A, 34 consecutive patients (16 males; 57 +/- 9 yrs) with a documented PAF and without any underlying heart disease, and Group B, normal controls (9 males; 44 +/- 6 yrs). A signal-averaged ECG, triggered with the oesophageal P-wave, obtained from an X, Y, Z lead system was recorded in each patient, utilizing the AEROTEL HIPEC 200 system. The three orthogonal averaged ECGs were band-pass filtered (non-recursive filter, 40-250 Hz) and combined into a spatial vector magnitudo. We evaluated the filtered P-wave duration (Ad, msec) and the Root Mean Square (RMS) voltages of the last 10, 20, and 30 msec of the P vector magnitudo (RMS 10, 20, 30; mcV).

RESULTS

The patients with PAF presented with a significantly longer Ad duration (A 126.6 +/- 12.4 vs B 96.8 +/- 12.5 msec, < 0.001), and lower amplitudes of RMS 10, 20, 30 (RMS 10 A 4.8 +/- vs B 9 +/- 2.7 p < 0.005; RMS 20 A 6.9 +/- 2.3 vs B 15.7 +/- 7.3 p < 0.005; RMS30 A 12.1 +/- 5.1 vs B 25.3 +/- 11.5 p < 0.005). An Ad > or = 100 msec, a value of RMS 10 < or = 6.5, RMS 20 < or = 9 and RMS 30 < or = 12.5 mcV showed high values of sensitivity, specificity and positive predictive value (Ad 85%, 100%, 100%, RMS10 93%, 80%, 90%, RMS20 84%, 90%, 96%, RMS30 72%, 90%, 72%). The combined duration/voltage criteria (Ad +/- 110 msec and RMS10 < or = 6.5 mcV or RMS20 < or = 9 mcV) showed a sensitivity of 80% and 76% with a specificity and positive predictive value of 100%.

CONCLUSIONS

The P-wave triggered transoesophageal atrial signal averaged ECG appears able to identify patients with PAF; however, prospective studies must investigate the possible clinical use of these findings.