Upright Retrograde P Waves

Report:

Ventricular tachycardia 154 - 142/min

Retrograde 1:1 conduction

Upright retrograde P waves?

Spontaneous termination after slowing to 142/min

Junctional escape complex

Non-specific ST/T changes

VEB

Comment:

The tachycardia resembles, superficially, LBBB with right axis deviation; it is a VT since this variant of aberrancy has not been observed8. Its morphology is identical to that of single VEBs recorded in other tracings (Fig 42a).

The interesting aspect of the retrograde P’ waves associated with this VT is that they are, or appear to be, upright. Normally, the “retrograde pattern” is that of inversion in 2, 3 and aVF and positivity in the three remaining limb leads. A report of this case19 and the related correspondence43 are available. I asked Marriott to “arbitrate”, but he stated that one cannot be sure, in this example, whether the retrograde atrial waves are truly upright in the inferior leads44. Marriott himself emphasised the trap of deceptive P wave polarity in his recent Pearls and Pitfalls15.

Curious case reports have, at least, the value of being considered in subsequent studies of the same subject; at least one study has reported biphasic retrograde P waves since20.