Diagnostic value of synchronized transesophageal atrial pacing.
Synchronized transesophageal atrial pacing (single and double extrastimuli) was used in 137 patients with various tachycardias inducible by atrial pacing during transesophageal electrophysiological study (EPS). This pacing mode in five patients initiated atrioventricular tachycardias with ipsilateral bundle branch block not seen when using other pacing modes. During the tachycardia, single or double extrastimuli caused ipsilateral bundle branch block disappearance in two patients with atrioventricular tachycardia, and changed AV activation ratio in one patient with atrioventricular junctional reentrant tachycardia. This pacing mode causes very little discomfort, what is important in children, and enhances diagnostic abilities of transesophageal EPS. So, this pacing mode should be used routinely as one of the steps of transesophageal EPS.