Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ ECG Findings ++ ST segment shortening and depression leading to a “scooped” appearance. QT interval shortening. PR interval prolongation. Decreased T-wave amplitude. Premature ventricular complexes are the most common dysrhythmia. Bradydysrhythmias, heart block, especially with findings consistent with increased automaticity (atrial tachycardia with block, atrial fibrillation with slow ventricular response, accelerated junctional rhythms). Bidirectional VT may rarely be seen (see Fig. 17.99). +++ Pearls ++ ECG changes associated with digoxin can be seen from therapeutic or toxic levels. ST-segment changes may be exaggerated by myocardial disease or tachycardia. An acute overdose of a digoxin is usually associated with hyperkalemia, which may increase the height of the T wave. Avoid calcium for treatment of hyperkalemia in the setting of digoxin toxicity as this may potentiate adverse effects of digoxin. ++ FIGURE 23.52A Digoxin Effect with Evidence of Toxicity. (ECG contributor: James V. Ritchie, MD.) Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ FIGURE 23.52B The “sagging” appearance of the ST segment (arrow) is characteristic of digoxin therapy and is not a sign of toxicity. However, this patient also has a sign of chronic digoxin toxicity. Atrial fibrillation is present, but the R-to-R interval has become regular. Digoxin toxicity has produced a total AV block but has also excited the AV node, producing a relatively accelerated junctional escape rate. Graphic Jump LocationView Full Size||Download Slide (.ppt) Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.