Which observation indicates the effectiveness of digoxin immune Fab treatment?

The effectiveness of digoxin immune Fab treatment is indicated by the restoration of normal sinus rhythm. Digoxin is a cardiac glycoside used primarily to treat heart failure and atrial fibrillation, and it exerts its effects by increasing the force of heart contractions and regulating heart rhythm. When digoxin levels are excessively high, it can lead to toxicity, which often manifests as arrhythmias or abnormal heart rhythms.

The administration of digoxin immune Fab serves as an antidote in cases of digoxin toxicity, working to bind the excess digoxin circulating in the bloodstream. A successful outcome of this treatment is reflected in the re-establishment of normal sinus rhythm, suggesting that the drug's toxic effects have been mitigated and the heart is functioning normally again.

While a digoxin level of 2.5 ng/mL might still be elevated depending on the individual’s normal therapeutic level, it does not signify the effectiveness of the antidote. Similarly, a decrease in blood pressure might be seen in various clinical scenarios but does not specifically indicate resolution of digoxin toxicity. A potassium level of 3.2 mEq/L is indicative of hypokalemia, which can actually contribute to the severity of digoxin toxicity rather than suggesting an effective treatment outcome. Thus