ECG Case 105

Rate:

• 150

Rhythm:

• Regular

Axis:

• LAD (~ 80deg)

Intervals:

• QRS – Prolonged (140ms)
• QT – 320ms

Additional:

• RBBB Morphology
  • Typical morphology

Interpretation:

• Regular Wide Complex Tachycardia
  • Clinical compromise evidence by chest pain and hypotension

General differential diagnosis include:

• Ventricular Tachycardia
• SVT with aberrancy
• SVT with pre-existing conduction delay
• SVT with pre-excitation
• Not applicable in this case but don’t forget paced rhythms

But what about this ECG? This ECG is most probably SVT (likely atrial flutter) with RBBB aberrancy as the principle diagnosis. The QRS activation pattern of rapid activation till QRS peak followed by slower activation is classic for RBBB aberrancy. 

The combination of RBBB and LAD (left axis deviation) means the SVT exit is the left posterior fascicle (left mid to basal LV), if this was VT it would be a fascicular VT.

Check out the links below for more on VT vs SVT with aberrancy and also on fascicular VT:

• ECG Library – Ventricular Tachycardia
• ECG Library – VT vs SVT with aberrancy
• ECG Library – Fascicular VT

What happened next?

…the patient underwent DC cardioversion in the Emergency Department and his post cardioversion ECG can be interpreted as Top 100 ECG Case 106