ECG of the Week - 30th December 2013 - Interpretation

The next ECG follows on the case of our patient from last week.
Following an out-of-hospital cardiac arrest the patient presented with ROSC.
The initial ECG on Emergency Department presentation can be found here.
Following initial treatment with iv adrenaline infusion, external pacing, a transvenous pacing wire was placed.
The resultant ECG is below.

Click to enlarge

Rate:

• Mean ventricular rate ~ 90 bpm

Rhythm:

• V-pacing
• Regular pacing spikes with capture
• Rate ~88 bpm
• 6th Complex native ventricular activity 
• Morphology similar to paced complexes\
• Atrial activity visible
• Best appreciated on rhythm strip
• Rate ~90 bpm

Axis:

• LAD (-65 deg)

Intervals:

• QRS - Prolonged (1~180ms)
• QT - 520ms

Segments:

• Discordant ST segment changes
• ST elevation leads II, III, aVF, V3
• ST depression leads I, aVL, aVR, V5-6

Additional:

• Discordant T wave changes
• T wave inversion leads I, aVL, aVR, V1-2
• Dominant R wave leads aVR, V1-2

Interpretation:

• VVI Pacing
• Secondary ST / T wave changes
• Single native ventricular complex
• Atrial activity without ventricular conduction

So what happend ?

Following stabilisation and transvenous pacing the patient was transferred to ICU for further management and investigation. Urgent coronary angiogram, CT head, and transthoracic echo were all normal ! During his ICU stay the complete heart block resolved and pacing wire was removed. Several days, after the initial out-of-hospital arrest the patient developed neurological signs and a transoesophageal echo (TOE) was performed to look for potential intracardial thrombus. The TOE revealed an aortic dissection (DeBakey type III, Stanford type B) this was treated conservatively and the patient was ultimately discharged.

Read more about aortic dissection, presentation, classifications, investigations, and management at the following blogs / sites:

Life in the Fast Lane

• Acute Aortic Dissection here
• DeBakey's Dissection here
• Lecture Notes: Aortic Dissection here

EMCrit

• Treatment of Aortic Dissection here

Emergency Medicine Ireland

• Does an anterior STEMI rule out dissection ? 

Crashing Patient

• Aortic Dissection

There is lots more out there on aortic dissection but the above are just a taster.

References / Further Reading

Life in the Fast Lane

• Pacemakers here

Textbook

• Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.