A pt is admitted due to abdominal pain, No palpitations/syncope.
Figure 1
The ECG showed short PR interval (PRI), delta wave
and widened QRS (WPW pattern) . After the 5th QRS there is progressive
shortening of the PRI and further widening of the QRS.
Figure 2
This appearance is referred as "concertina
effect" of preexcitation.
Concertina form of pre-excitation is a reliable
predictor of a relatively long refractory period and thus a marker of low risk
of sudden death.
References:
Knight, BP. Anatomy, pathophysiology and localization
of accessory pathways in the preexcitation syndrome. In: UpToDate, Downey B
(Ed), UpToDate, Waltham, MA. (Accessed on August 10,2015.)
Marco P et al.2009. Adding an Electrocardiogram to
the Pre-participation Examination in Competitive Athletes: A Systematic Review.
Curr Probl Cardiol ;34:586-662
Surawicz B and Knilans TK. 2008. Chou’s
Electrocardiography in Clinical Practice. 6th ed. PA. Saunders-Elseiver
Vivek S et al. 2013. Concertina effect: a subtle but
specific marker. BMJ Case Rep (http://casereports.bmj.com/content/2013/bcr-2013-009328.full)
#633
NICE case! The principal differential diagnosis is between the Concertina Effect (that you show here) — and sinus rhythm with end-diastolic ( = end-cycle) PVCs that nearly coincide with the sinus-conducted QRS complexes. The fact that there is underlying sinus arrhythmia in this example makes it more difficult to assess — but I like lead aVR which to me clearly shows varying degrees of preexcitation for the negative delta wave in this lead. Thanks for presenting!
ReplyDeleteNice explanation
ReplyDeleteThe Concertina effect is one of those findings that, as you'd mentioned, reduce the risk of SCD associated with WPW given the implied long refractory period of the AP. Other findings include intermittent preexcitation (including "WPW alternans") as well as obliteration of preexcitation with exercise.
ReplyDelete