Crying Wolff with Surprising Outcome

Report:

Supraventricular, possibly junctional, rhythm 54/min

Wolff-Parkinson-White conduction, type ‘B’

Comment:

One cannot be completely certain of the provenance of the atrial impulses; they are flat or biphasic in the frontal plane leads. In V1, however, the morphology is that of a predominantly positive retrograde P wave, suggesting junctional origin. The short PR interval cannot, of course, be adduced in evidence for the junctional origin – it is short because of the δ wave itself.

The main differential diagnosis of this trace is from junctional or atrial rhythm with LBBB and from isorhythmically dissociated AIVR; the former is excluded by the clear-cut δ wave, the latter by the absolute fixity of the P-QRS relationship.

A recording in sinus rhythm is shown below, with a single junctional extrasystole (the 4th beat). The QRS morphology remains unchanged. This, at least, rules out ectopic atrial rhythm causing WPW-like QRS changes37. The QRS is relatively slender, suggesting that there is, both in sinus beats and in the extrasystole, a major contribution through the normal A-V pathway. This, in turn, suggests the site of anomalous conduction of the putative junctional rhythm to be the paraspecific fibres of Mahaim rather than the more usual bundle of Kent38. However, things were not what they seemed.

The patient developed an episode of atrial fibrillation (Fig 61b), again with identical QRS complexes; this was very strange for WPW syndrome. He was then sent to John Hunter Hospital in Newcastle, where an EPS revealed that he did not have WPW syndrome at all. The EPS report is on the page following Fig 61b.

Fig 61a. Definite sinus rhythm, same QRS morphology.

Fig 61b. In AF, the QRS complex is identical to that in Fig 61 and 61a.

Fig 62. 70 year old man with unpredictable blackouts for the past fortnight.