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Physiology · Cardiovascular system: digoxin effect on ECG
Sample itemA 70-year-old with heart failure on long-term digoxin has an ECG showing downsloping, scooped ST segment depression in the lateral leads. What does this represent?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
C. Digoxin effect from altered repolarisation, not toxicity
Digoxin shortens the ventricular action potential and produces a scooped ST depression, a therapeutic effect that does not mean toxicity. Toxicity gives arrhythmias such as atrial tachycardia with block and ventricular ectopy.
Option by option
A. Pericarditis
Pericarditis causes diffuse concave ST elevation and PR depression.
B. Acute transmural infarction
Transmural infarction causes ST elevation, not scooped depression.
C. Digoxin effect from altered repolarisation, not toxicity (correct)
Correct. Scooped ST depression is the expected effect of digoxin on repolarisation.
D. Hyperkalaemia
Hyperkalaemia causes tall peaked T waves and a widened QRS.
Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.
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