His bundle electrocardiography during routine left heart catheterisation.

The value of His bundle electrogram recording has been previously established. A technique to allow routine inclusion of brief duration His bundle electrogram recording during retrograde left heart catheterisation has been developed using a standard pigtail ventriculography catheter with the addition of a 'Y' hub fitting providing a sealable port for introduction of an electrode wire and a side arm for continuous pressure monitoring and flushing. With the catheter in place the electrode wire is advanced to the level of the proximal side hole of the catheter and provides a unipolar intracavitary lead. Positioned to record the His bundle electrogram the catheter lies with the proximal hole (and elec- trode tip) just below the aortic valve leaflets. The position is stable and the left bundle-branch is not recorded. In 24 of 27 patients reliable His bundle electrograms were recorded by this technique and verified by simultaneous standard His bundle electrograms recorded from the right heart and with atrial pacing. Satisfactory His bundle electrograms were most easily obtained in patients with vertical hearts. Those few in whom it was more difficult or unobtainable had horizontal hearts.