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Wolff-Parkinson-White (WPW) syndrome is characterised by the presence of an accessory pathway with typical electrocardiography (ECG) changes of short PR interval, slurred delta wave and widened QRS complexes. In WPW Type A, the presence of Q wave and Q/T vector discordance in inferior leads can simulate inferior infarction; at the same time, WPW syndrome can also mask the ECG changes of ST elevation myocardial infarction.(1) We herein report a case of a 63-year-old man with no known illness presenting with acute chest pain of six hours’ duration.
ECG showed the presence of WPW Type A (left accessory pathway) with no overt ST changes associated with infarction (
(a) ECG shows Wolff-Parkinson-White features in leads III and aVF, fragmented QRS complexes (black arrows) and Q/T vector concordance. Coronary angiograms show the (b) occluded and (c) post-stenting right coronary artery.
The delta wave in WPW syndrome can simulate inferior infarction by producing pseudo-infarct Q waves in leads II, III and AVF. Goldberger(2) has suggested that a discordant T wave (opposite the Q wave) should be the norm in WPW Type A; however, if inferior infarction is suspected, the T wave should be concordant.(2) A lesser-known fact is that WPW syndrome can also mask the ECG changes of inferior myocardial infarction, as the delta wave vector will oppose and obliterate the initial vectors of infarction, producing a normal-looking ECG.(3) In our case, the subtle signs pointing to an ongoing infarction in
Diagram shows different patterns of RSR and fragmented QRS complexes (white arrows).
Das et al defined fQRS as QRS complexes with the presence of an additional R wave (R’) or notching in the nadir of the R or S wave, or the presence of > 1 R’ (fragmentation) in two contiguous leads, corresponding to a major coronary territory (
In conclusion, this case illustrates how ST segment elevation acute myocardial infarction can be masked in patients with pre-existing WPW syndrome. However, comprehensive analysis of the ST-T wave concordance and fragmentation of the QRS complexes helped us to spot the infarction and identify the infarct-related artery.
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