Digoxin effect refers to the presence on the ECG of:
Other features of digoxin effect
The morphology of the QRS complex / ST segment is variously described as either “slurred”, “sagging” or “scooped” and resembling either a “reverse tick”, “hockey stick” or (my personal favourite) “Salvador Dali’s moustache”!
The most common T-wave abnormality is a biphasic T wave with an initial negative deflection and terminal positive deflection. This is usually seen in leads with a dominant R wave (e.g. V4-6). The first part of the T wave is typically continuous with the depressed ST segment. The terminal positive deflection may be peaked, or have a prominent U wave superimposed upon it.
The ECG features of digoxin effect are seen with therapeutic doses of digoxin and are due to:
- Shortening of the atrial and ventricular refractory periods — producing a short QT interval with secondary repolarisation abnormalities affecting the ST segments, T waves and U waves.
- Increased vagal effects at the AV node — causing a prolonged PR interval.
NB. The presence of digoxin effect on the ECG is not a marker of digoxin toxicity. It merely indicates that the patient is taking digoxin.
- This is the classic picture of digoxin effect with the “sagging” ST segments and T waves taking on the appearance of “Salvador Dali’s moustache”.
- Sagging ST segments are most evident in the lateral leads V4-6, I and aVL.
Another example of digoxin effect:
- The sagging morphology is most evident in V6 and in the lead II rhythm strip.
This is a slight variation on the classic digoxin pattern:
- There is still downsloping ST depression but it is slightly more angular, in comparison to the “sagging” ST segments from the previous example.
- Also, there is J-point depression in V4-6, which mimics the appearance of left ventricular hypertrophy.
- The short QT interval, the “sagging” appearance in the inferior leads and the lack of voltage criteria for LVH indicates that this is digoxin effect rather than LVH.
- Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice (6th edition), Saunders 2008.
- Wagner, GS. Marriott’s Practical Electrocardiography (11th edition), Lippincott Williams & Wilkins 2007.