Special infarction patterns are non-Q wave infarctions.

1. Patterns without Q waves
   1. Symmetric negative T waves (classical non-Q wave infarction)
   2. ST depression > 3 mm

ECG Tracing With ST Depression > 3 mm

2. R waves with reduced amplitude and Q waves with a duration < 0.04 seconds in the classical leads for inferior infarction detection (such as aVF and III)

ECG Tracing of Reduced R Wave Amplitude in Lead V₃

3. The appearance of small, new Q waves lasting < 0.04 seconds
4. rsR’ or rSr’ patterns in leads I, aVL, and/or in V₅, and/or V₆. rSr’ and rSr’ patterns are seen in patients with an extensive anterior wall MI. Sometimes these patterns are also present on the ECG of patients with hypertrophic nonobstructive cardiomyopathies with intraventricular conduction defects.

rSr’ Pattern in Lead V₆

The classical non-Q wave infarction may also be seen in items 2 to 4 above. When present, this makes for a more confident diagnosis of a non-Q wave infarction. This is the most frequent pattern, which is often seen in precordial leads V₁ through V₆ and often in leads I and aVL along with an R wave with a normal or slightly reduced amplitude.