Case B17. Atrial Fibrillation 4. St Emlyn’s ECG Library.

Case B17. Atrial Fibrillation 4. St Emlyn's ECG Library.


This ECG was taken from a patient taking Digoxin to control their atrial fibrillation rate.


Rhythm: No recognizable P waves or other form ofcoK)rdinated atrial activity is seen in any lead. The baseline is irregular and atrial activity is best seen in lead VI where anirregular waveform of low amplitude is recorded. The QRS complexes are irregular, the R – R intervals vary unpredictably.There is no recognizable relationship between the QRS complexes and atrial activity: atrial fibrillation is present. Inthe rhythm strip several wide (greater than .10 second) QRS complex beats are seen. These are probably ventricular premature beats although the alternative possibility ofaberrant conduction of isolated beats whose origin is supraventricular cannot be excluded from this trace. The factthat there are three different morphologies for these premature beats makes a ventricular origin almost certain.

Morphology: There are downsloping ST segments andinverted T waves in leads I, II, aVL, aVF and V4, V5 and V6. This finding is non-specific but could be caused by either digoxin or ischaemia.


The atrial fibrillation in this case is ‘finer* than noticed in the previous examples. This may be a feature of longstanding  atrial fibrillation, although the random chaotic atrial depolarization is still clearly visible in VI and V2. In this case the serum digoxin level was elevated.This was felt to be responsible for the ST-T changes and additional beats.

Cite this article as: Simon Carley, "Case B17. Atrial Fibrillation 4. St Emlyn’s ECG Library.," in St.Emlyn's, November 18, 2018,

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