The EGG was recorded from a 32 year old man with a history of palpitation. His application for a large goods vehicle licence had been rejected because his EGG (done becauseof the history of palpitation) was said to indicate an old myocardial infarct.
ECG. Rhythm: Sinus rhythm is present throughout.
Morphology: The PR interval is short and the P wave merges into a broad slurred delta wave particularly well seen in leads I, aVL and V2 – V6. There are tall R waves in the right sided precordial leads (VI – V3). In the inferior leads (III and aVF) there is a Q wave; T wave flattening or inversion is also present in these leads.
Comment. The appearances are of ventricular pre-excitation and are compatible with Wolff Parkinson White type A. In this condition the AV nodal bypass tract passes to the left ventricle and initiates ventricular depolarization. The resulting delta wave is directed anteriorly and this results in a positive wave in the anterior leads. The delta wave is also directed superiorly and it is this that gives rise to a negative deflection in the inferior leads. These initial negative waves are quite properly described as Q waves but they do not provide evidence of infarction. The delta wave may be directed superiorly in WPW of both type A and type B with the result that the inferior leads show initial Q waves. For this reason the presence of Q waves or QS waves in any lead cannot be taken to indicate infarction when ventricular pre-excitation is present.
When it was realised that the EGG did not provide evidence of infarction in this patient, he was able to reapply for his HGV licence.