The Patient This ECG was obtained from a 74-year-old man who had a history of COPD. He was complaining of severe chest pain at the time of the ECG.
The ECG The rhythm is atrial fib or flutter (the R to R intervals are irregular, but seem to repeat about 4 interals). Flutter waves are seen during some of the longer intervals. The rate is approximately 90 beats per minute. The ST segments are very noticeably elevated in Leads II, III, and aVF. There is reciprocal ST depression in Leads I and aVL, and also in all the precordial leads.
There is poor R wave progression, with the transition from negative to positive in V5. The QRS width is difficult to determine with so much ST elevation and depression. Lead I and Leads V4 through V6 have fairly clear onset and offset (J point), and appear to be about .09-.10 seconds. There are possible pathological Q waves in the precordial leads: V1 through V4. If this represents old anterior wall M.I., that would explain the poor R wave progression.
Discussion This patient has definitely earned a trip to the cath lab. The ST elevations in related leads II, III, and aVF with expected reciprocal changes in Leads I and aVL are indicative of Inferior Wall ST elevation M.I. (STEMI). The rate is faster than we would like to see in an injured heart, and attempts will be made to slow it with medication. The ST depression in the precordial leads could have several causes, including subendocardial ischemia. It is common to see LOCALIZED ST depression in V1, V2, and V3 with inferior wall M.I., indicating extension of the damaged tissue up the posterior wall. The patient’s preexisting pulmonary disease could also be causing ST changes, as well as the poor R wave progression and the arrhythmia. Sadly, we do not have a previous ECG for comparison, or any information on the patient’s outcome.
For teaching purposes, this ECG is excellent for illustrating the difference between wide QRS and tall ST elevation. Since all four channels on this ECG are run simultaneously, we only have to compare the QRS complexes that look “wide” (II and III) to the complexes directly above (I), and we will see that the ST segment is masquerading as a wide QRS.
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