[Left atrial lead and stimulation in wpw-syndrome type A (author's transl)]

Normal and accessory A-V conduction were analyzed by His bundle recordings in a 49-year-old patient with WPW-syndrome type A. An open foramen ovale permitted registration of left atrial potentials as well as left atrial pacing. The effects of the pacemaker site (left or right atrial pacing) on the electrocardiographic variability of pre-excitation were studied. The effective refractory period of the accessory A-V conduction was shown to be dependent on the site of pacing. Recordings of right and left atrial potentials during runs of supraventricular tachycardia demonstrated that V-A conduction occurred via the accessory pathway.