ECG Review: Has There Been an Infarct?
ECG Review
Has There Been an Infarct?
By Ken Grauer, MD, Professor, Department of Community Health and Family Medicine, University of Florida. Dr. Grauer is the sole proprietor of KG-EKG Press, and publisher of an ECG pocket brain book.
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Scenario: The ECG tracing shown above was obtained from a 50-year-old man with a history of longstanding hypertension.
Interpretation: The rhythm is normal sinus rhythm at 60/minute. Intervals are normal. There is significant left axis deviation (LAD) sufficient to qualify as left anterior hemiblock (LAHB), since the QRS complex in lead II is predominantly negative (which places the QRS axis at more negative than -30º). There is no chamber enlargement.
The remarkable findings on this tracing lie with assessment of Q-R-S-T morphology. There is a deep Q wave (QS complex) in lead III; a subtle r' in lead V1 with some concave upward J-point ST segment elevation in V1,V2; early transition between V1-to-V2 (with a surprisingly tall R wave already by lead V2); and persistence of S waves throughout the precordial leads. The significance of these findings in our descriptive analysis is uncertain. Isolated Q waves (even when deep) are often found in leads III and/or aVF without necessarily implying that there has been prior inferior infarction. Unless there are Q waves in each of the 3 inferior leads (II, III, and aVF), we tend to interpret this finding as a "Q wave in lead III of uncertain significance." A terminal r' in lead V1 and persistence of S waves across the precordial leads are findings that are often associated with pulmonary disease but the rest of this tracing is not suggestive of this. Slight J-point ST elevation with upward concavity in a few isolated anterior leads, in the absence of other evidence of acute infarction, is usually a benign finding.
The most eye-catching finding on this tracing is the abrupt early transition caused by the unexpectedly tall R wave in lead V2. Possible reasons for this finding include posterior infarction, cardiomyopathy, abnormal body habitus or anatomic chest wall abnormality, and lead misplacement. Clinical correlation (and comparison with a prior tracing) is essential to determine which of these possibilities may be operative.
The ECG tracing shown above was obtained from a 50-year-old man with a history of longstanding hypertension.Subscribe Now for Access
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