Mori Quartet Part 3

Figure 1

+ What are the significant findings in this ECG of a 61 year old man who 3 days ago had (a unsuccessful) percutaneous coronary intervention procedure for an acute myocardial infarct, and who has had a recurrence of chest pain?

The rhythm is sinus and the heart rate is about 100 beats per minute.
The frontal plane axis is normal.
The most obvious abnormalities are:

  • Q waves in Leads II, III, aVF and in Leads V1 to V3.
  • ST elevation and upright T waves in Leads II, III, aVF and in Leads V1 to V6.

These changes are those of a acute ST-segment elevation myocardial infarct (STEMI). We have listed all the leads that are affected by these changes, a rather cumbersome process. We can greatly simplify our description by saying that the STEMI changes are "widespread" or "extensive", but this is imprecise. In practice we use a "ECG shorthand" that is based on the observation that the ECG changes in myocardial infarction affect groups of leads:

  • the inferior leads, which are Leads II, III and aVF
  • the anterolateral leads, which are are Leads I and aVL
  • the anterior (precordial) leads, where the involved leads can be subdivided into anteroseptal (Leads V1 to V3), lateral (Leads V5 and V6) or extensive (Leads V1 to V5 or V6).

In this case STEMI changes are present in two groups of leads:

  • the inferolateral leads (II, III, aVF, V5 and V6)
  • the anteroseptal leads (V2 - V4)

A common pattern of ECG changes in a STEMI is the presence of ST elevation in one group of leads and ST depression in the other leads e.g. inferior lead ST segment elevation with anterior ST segment depression; anterior lead ST segment elevation with inferior ST segment depression.

Here we have ST segment elevation (and upright T waves) in the inferolateral leads and anteroseptal leads. The PQ segment is elevated in Lead aVR and depressed in Lead II, a sign of pericarditis.

An echocardiogram in this case showed a pericardial effusion.

Important Points

  • Pericarditis (PQ segment is elevated in Lead aVR and depressed in Lead II) in an ECG with a acute (STEMI) injury pattern in both anterior and inferior leads
  • The GUSTO study found that a combined anterior and inferior ST elevation pattern was present in six percent of patients with a acute myocardial infarct, with sixty percent of cases due to a occlusion of the right coronary artery (Chou's Electrocardiography in Clinical Practice. B Surawicz, TK Knilans. Sixth Edition 2008 Saunders Elsevier).
  • Dr Smith's ECG blog presented a case of anteroseptal STEMI with persistent ST elevation and upright T waves who developed a rupture of the ventricular septum and died. He commented: "Well formed Q-waves with persistent ST elevation, especially in a patient with prolonged pain, should alert to transmural MI with possible post-infarction pericarditis. One should be on the alert for myocardial rupture".