Reperfusion: Rapid Development of Q Waves

Report:

Sinus rhythm 63/min

ST/T changes c/w infarction/ischæmia

Comment:

This is somewhat atypical tracing in that the prominent T waves are narrow-based and pointed, the ST elevation is modest and horizontal and there are no reciprocal changes in the inferior leads. It still qualifies as ST elevation infarction for therapeutic purposes. The patient was reperfused (proven at subsequent angiography) by rt-PA even though the ST segments remained elevated (Fig 29a, 5 hours later). What is remarkable is the rapid development of Q waves (and loss of R waves) in the anterior leads, presumably as the result of reperfusion21.

Lack of reciprocal changes in this case may be due to the left anterior descending artery also supplying the inferior wall directly (wraparound LAD) or through collaterals to previously occluded left posterior descending artery in the setting of old inferior infarction22. A second look at the ECG shows some evidence for the latter.

Below (Figs 29b, 29c) is another example, with inferior MI in a 40 year old man. 29a. New anterior Q waves.

29b. Acute inferior MI on admission in Casualty, where r-tPA was administered.

29c. Five hours later, in CCU, the ECG is normalised except for the new pathological Q waves in the inferior leads.

30. 14 year old girl with Strep. viridans mitral endocarditis and sudden onset of central chest pain.