TRANSESOPHAGEAL ATRIAL-PACING THRESHOLD FOR INITIATION OF LATE POTENTIAL

To evaluate transesophageal atrial pacing threshold for initiation of ventricular late potential during accelerated heart rate, we recorded the signal averaged ECG during bipolar transesophageal atrial pacing w ith hemispherical electrode (6mm diameter) in 26 patients with and wit hout myocardial infarction. 26 patients with transesophageal atrial pa cing at 9.9 ms stimulus duration had 6.9 +/- 2.1 mA capture threshold for bipolar transesophageal atrial pacing and 22 patients 5.6 +/- 1.9 mA feeling threshold for bipolar transesophageal atrial pacing. The mi nimum of the capture threshold for transesophageal atrial pacing was 4 mA at 9.9 ms. In 10 patients the capture threshold for transesophagea l atrial pacing was lower or equal than the feeling threshold for tran sesophageal atrial pacing. The minimum of the feeling threshold for tr ansesophageal atrial pacing was 3 mA at 9.9 ms. In 12 patients the cap ture threshold for transesophageal atrial pacing was 2.6 +/- 1.3 mA hi gher than the feeling threshold. In conclusion, the combination of bip olar transesophageal atrial pacing at 9.9 ms stimulus duration and hem ispherical electrode allowed transesophageal low amplitude atrial paci ng with low feeling threshold and low capture threshold for initiation of late potential during accelerated heart rate.