Concertina effect in WPW syndrome

Concertina effect in WPW syndrome

Abstract: Varying QRS width in WPW syndrome due to varying degrees of pre-excitation is known as concertina effect in WPW syndrome. The more the pre-excitation, the shorter the PR interval and wider the QRS duration.

Progressive decrease in PR interval with reciprocal increase in QRS width due to changing degree of pre-excitation has been termed concertina effect in WPW syndrome. It may be noted that the PJ interval (from the beginning of P wave to the end of QRS) remains constant.¹ It has been mentioned that those manifesting concertina effect is likely to have higher accessory pathway refractory period.² This would translate to lower ventricular rates in case of occurrence of atrial fibrillation and hence lesser chance of sudden cardiac death. It may be noted the WPW syndrome with atrial fibrillation is a potentially life threatening situation because of the very fast ventricular rates which can lead on to ventricular fibrillation. Atrial fibrillation with fast ventricular rate is encountered in accessory pathways with short refractory periods, typically less than two hundred and fifty milliseconds.

Concertina effect has been described during an episode of vasospastic angina in a person with WPW syndrome.³ In this case, a gradual prolongation of AH interval was documented in the His bundle electrogram.

References

1. Giraud G, Latou H, Puech P, RouJon J. Rhythm disorders of the WPW syndrome, endocavitary electrocardiographic analysis. Montpellier Med. 49: 101, 1956.
2. Singla V, Singh B, Singh Y, Ravindranath KS. Concertina effect: a subtle but specific marker. BMJ Case Rep. 2013 Apr 30;2013. pii: bcr2013009328. doi: 10.1136/bcr-2013-009328.
3. Nakagawa S, Maeda K, Imamura T, Kondoh H, Koiwaya Y, Tanaka K. Increasing pre-excitation (“concertina effect”) during vasospastic angina. J Electrocardiol. 1986 Jul;19(3):299-302.