14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-198

Transesophageal atrial pacing with different electrodes for initiation of late potential in patients after acute myocardial infarction

Matthias Heinke, Helmut Kühnert, Frank-Michael Malur, Ralf Surber, Gundrun Dannberg, Hans-Reiner Figulla.
University Hospital of Internal Medicine III, Division of Cardiology, Jena, Germany

Methods

We recorded the QRS triggered signal averaged ECG with 2000 Hz sampling rate during spontaneous rhythm and 1000 Hz sampling rate during transesophageal atrial pacing with Predictor (Corazonix, Corp., Oklahoma City, OK, USA) signal averaging system and 16 bit analog-to-digital converter model DT 2801/5716A (Data Translation, Inc., Marlboro, MA, USA) for analysis of ventricular late potential during spontaneous rhythm with 300 ms time window and transesophageal atrial pacing with 600 ms time window. For transesophageal atrial pacing with different electrodes with and without electrical insulation, we used the programmable stimulator model 5328 (Medtronic, Inc., Minneapolis, MN, USA) with constant current stimulus output from 0.1 to 9.9 ms stimulus duration and 0.1 to 28 mA stimulus current amplitude and the programmable stimulator 8817 (Fiab, Florence, Italy) with constant transesophageal current stimulus output from 5 to 20 ms stimulus duration and 5 to 45 mA stimulus current amplitude.

We used the cylindrical hexapolare electrode (Vygon, Aachen, Germany) without electrical insulation with 4 mm diameter and 10 mm length cylindrical electrodes in 18 patients and the hemispherical electrode with electrical insulation and 6 mm diameter hemisherical electrodes in 14 patients (Fig. 1).

Fig. 1: Hemispherical electrode for low threshold transesophageal atrial pacing with 1 cylindrical electrode with 4 mm diameter on the tip of the electrode and 5 hemispherical electrodes with 6 mm diameter without electrical insulation on the heart side of the electrode.

For evaluation of effective or ineffective transesophageal atrial pacing, we analysed the high amplified bipolar unfiltered signal averaged ECG leads X, Y and Z. We detected ineffective transesophageal atrial stimulation impulses in the 600 ms time window of the signal averaged ECG in the high resolution unfiltered signal averaged ECG with superposition of an ineffective atrial stimulation impulse with ventricular late potential.