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This ECG was recorded 24 hours later. Note the persistent injury pattern in II, III, aVF. Q-waves have appeared in these leads indicating inferior necrosis or infarction. The resultant loss of inferior myocardium has shifted the frontal plane axis superiorly (or leftward).

There is also persistent ST depression in Leads V1 through V4 and look what has happened to the R-waves in those leads. They're very tall. This development of tall R-waves in the right precordium should be interpreted as evidence of POSTERIOR myocardial infarction. The horizontal axis is therefore shifted anteriorly.

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