Digitalis (digoxin) effect on ECG often shows scooped ST segments and flattened T waves. What is this called?

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Multiple Choice

Digitalis (digoxin) effect on ECG often shows scooped ST segments and flattened T waves. What is this called?

Digitalis effect on the ECG is the pattern described: a scooped (downward-sloping) ST segment with flattened T waves. This is a classic, non-pathologic drug effect seen with digoxin therapy, and it can appear even at therapeutic levels. The reason it shows up this way is linked to digoxin’s action on cardiac cells. Digoxin inhibits the Na+/K+-ATPase pump, which increases intracellular sodium. That reduces the driving force for the Na+/Ca2+ exchanger, leading to higher intracellular calcium and enhanced myocardial contractility (positive inotropy). It also increases vagal tone and slows conduction through the AV node, which is why digoxin is useful for controlling ventricular rate in atrial tachyarrhythmias. The ST-T changes reflect altered repolarization and are a recognized electrocardiographic sign of the drug’s effect rather than a primary rhythm disturbance. If digoxin were toxic, you’d expect additional problems such as arrhythmias or conduction blocks, but the scooped ST and flattened T waves by themselves point to the digitalis effect.

Digitalis effect on the ECG is the pattern described: a scooped (downward-sloping) ST segment with flattened T waves. This is a classic, non-pathologic drug effect seen with digoxin therapy, and it can appear even at therapeutic levels.

The reason it shows up this way is linked to digoxin’s action on cardiac cells. Digoxin inhibits the Na+/K+-ATPase pump, which increases intracellular sodium. That reduces the driving force for the Na+/Ca2+ exchanger, leading to higher intracellular calcium and enhanced myocardial contractility (positive inotropy). It also increases vagal tone and slows conduction through the AV node, which is why digoxin is useful for controlling ventricular rate in atrial tachyarrhythmias. The ST-T changes reflect altered repolarization and are a recognized electrocardiographic sign of the drug’s effect rather than a primary rhythm disturbance.

If digoxin were toxic, you’d expect additional problems such as arrhythmias or conduction blocks, but the scooped ST and flattened T waves by themselves point to the digitalis effect.

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