Pehrson SM, Blomstrom P.Kardiologkliniken, Lunds Lasarett, Sverige. Ugeskr Laeger 1991 Nov 25;153(48):3403-7. Paroxysmal supraventricular tachycardia (PSVT) includes a group of common arrhythmias. The diagnosis should be based on 12-lead ECG. Oesophageal ECG, which registers mainly left-sided posterior atrial activity may be of value for further assessment of the arrhythmic mechanism in determination of the time relationship between atrial and ventricular signals. A ventriculoatrial interval during PSVT measured by oesophageal ECG of under 70 ms is evidence of atrioventricular nodal re-entry tachycardia while an interval of over 70 ms suggests orthodromic reciprocating tachycardia with participation of an accessory atrioventricular pathway. Transoesophageal atrial stimulation (TAS) via an electrode catheter is possible in approximately 90% of the patients with PSVT. TAS requires greater quantities of energy than endocardial stimulation and is associated with slight to moderate retrosternal discomfort. The method renders possible both programmed stimulation with the object of inducing arrhythmia and in stopping the majority of cases PSVT, with the exception of atrial fibrillation. The method is relatively simple, non-invasive, requires few resources and can be carried out on outpatients.