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NSTEMI

Instructors' Collection ECG: Atrial fibrillation and Type 2 M.I.

Sat, 07/20/2019 - 13:41 -- Dawn

The Patient:     This excellent teaching case was donated to the ECG Guru by our friend, Sebastian Garay (who is an ECG Guru himself).  It was taken from a 33-year-old man who was complaining of chest pain and palpitations. He reported a similar episode about six months prior, but failed to follow up with cardiology. Was told by his medical care provider that he had atrial fib.

The ECG:      We are able in this case to provide a 12-lead ECG with each lead recorded for the entire width of the paper. This has the advantage of producing twelve ten-second rhythm strips.  Page one contains the limb leads, and page two shows us the precordial leads.

The rhythm is atrial fibrillation, with a heart rate of 133 bpm and an irregularly irregular rhythm. The QRS axis is extreme left at about 75 degrees.  This has caused Leads II, III, and aVF to be negatively deflected, and aVR and aVL to be positive. Lead I is biphasic, low voltage, and mostly positive, indicating that the axis travels almost perpendicular to Lead I, but slightly toward it.

The machine mistakenly gives us a reading for PR interval and P wave axis, even though there are no P waves.  The QRS is on the wide side without being abnormal at .10 seconds (100 ms). The QTc is within normal limits, although it might be considered “borderline”, with 431-450 usually considered borderline.

Acute M.I.: Occluded Stents in Left Obtuse Marginal Artery

Sun, 07/28/2013 - 15:02 -- Dawn

This ECG illustrates what some would call a non-ST-elevation M.I., but may also illustrate the limitations of a standard 12-Lead ECG.  This female patient in her 60's presented to the Emergency Department with vague chest discomfort.  She was cool and diaphoretic.  She gave a history of having coronary artery stents placed in the past.  On angiography in the cath lab, she was found to have two stents in her obtuse marginal artery which were occluded.  Her case was lost to followup.

The ECG shows ST depression in anterior leads V2 through V6, as well as in the inferior leads, although very subtle.  The inferior leads' ST segments are more horizontal than depressed, but flat and horizontal is not normal.  She shows a bit of upward concavity or slight elevation in V1, Lead I, and aVL.  These signs might be missed by someone looking only for ST ELEVATION.  Additional left lateral and posterior leads were not done, and we have to wonder if she would have had some ST elevation in V7 or V8.

Her rhythm is very interesting too.  Often, ischemic hearts produce abnormal rhythms, and it is not unexpected.  The rate and the rhythm caused this patient no difficulties during her time in the ED.  On first glance, her QRS complexes appear to be "grouped", as they would in a Wenckebach type block.  On closer inspection, you will see two distinctly different P waves, and no non-conducted P waves.  This appears to be a sinus rhythm with frequent PACs.  The PRI is prolonged at .28 sec., which also is not unusual for M.I. patients.

We are very interested to hear what YOU think about this interesting ECG, including the rhythm.  We are hoping to hear from people from all areas of cardiac care - what do you think are the main teaching points of this case?

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