Tuesday, November 29, 2011

Atrial Flutter Mimicking ST Depression

A 65 year old presented with altered mental status and had an intracranial bleed:
One could be fooled into thinking this is sinus tachycardia (with a short PR interval) with diffuse ST depression.  But close inspection reveals flutter waves.  In particular, a totally upright p-wave in V1 is very unusual and should alert you to atrial flutter.  The fluttering baseline accounts for the apparent ST depression, although I cannot rule out some amount of true ischemic ST depression.

 Here is the ECG after cardioversion:
Now there is sinus.  Interestingly, this one also has an upright p-wave in V1 - so the rule is not universal!


  1. Dr. Smith,
    the P Wave in Sinus is really upright, but also in II, III there its somewhat biphasic and in aVR slight positiv, isnt it somewhat atypical for Sinus??

    1. Martin,
      good point. It is atypical.
      It's possibly a non-sinus atrial rhythm.

  2. Great Post! The Systematic Approach "Watch your Ps, Qs and the 3 Rs" is useful. The rhythm in first ECG is a regular SVT (Narrow & Regular/SupraVentricular Tachycardia) at ~130/minute without clear sign of sinus P waves. The pattern of ST segment deviation that we see here (ie, ST depression in no less than 7 leads — with ST elevation in aVR & V1-3) is suggestive of subendocardial ischemia. There is LVH(deep S wave in V1 ~28 mm and 30 mm in V2). As per Ken KEN GRAUER the principal differential diagnosis of a regular SVT without clear sign of sinus P waves includes: i) Sinus Tachycardia; ii) Reentry SVT (either AVNRT if the reentry circuit is contained within the normal AV nodal pathway — or AVRT if an accessory pathway is involved); iii) Atrial Tachycardia; or iv) Atrial Flutter. Regularly occurring peak to peak or valley to valley of the flutter waves would be easily appreciated in lead V1 and lead II respectively in Aflutter, but I can't see this in first ECG.I want to know why isn't the other(such as AVNRT or AVRT; Atrial Tachycardia)?. Why AFlutter? Thanks A LOT.


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