Okay, let's tackle this question about the best treatment for digoxin-induced arrhythmias. First, I need to recall the core concept here. Digoxin toxicity can cause various arrhythmias, and the management involves specific antidotes.

The core concept is understanding the mechanism of digoxin toxicity. Digoxin works by inhibiting the Na+/K+ ATPase pump, leading to increased intracellular sodium and decreased potassium. This affects calcium levels, increasing contractility. However, in toxicity, this mechanism can lead to arrhythmias. The antidote for digoxin is digoxin immune Fab (DigiFab), which binds to digoxin and neutralizes its effects.

Now, the correct answer should be the antidote, which is DigiFab. Let's think about why other options are wrong. For example, if the options include calcium, that's a red herring because calcium can worsen digoxin toxicity. Potassium is sometimes used to manage arrhythmias in digoxin toxicity, but excessive potassium can be dangerous, so it's not the best. Lidocaine or other antiarrhythmics might be used for specific arrhythmias but don't address the underlying toxicity.

Clinical pearls: Remember that DigiFab is the specific antidote, and calcium should be avoided. Also, potassium is used cautiously. High-yield fact: DigiFab is the first-line treatment for severe digoxin toxicity, especially in life-threatening arrhythmias.

**Core Concept** Digoxin toxicity causes arrhythmias by inhibiting Na+/K+ ATPase, leading to intracellular calcium overload and membrane instability. The antidote must neutralize digoxin's effects without exacerbating electrolyte imbalances.

**Why the Correct Answer is Right** Digoxin immune Fab (DigiFab) is the specific antidote. It binds digoxin molecules in the bloodstream, forming a complex that is excreted by the kidneys. This reverses toxicity by reducing free digoxin concentration, stabilizing cardiac membranes, and restoring normal electrolyte gradients.

**Why Each Wrong Option is Incorrect**
**Option A:** Calcium (e.g., calcium gluconate) worsens digoxin toxicity by enhancing its effects on the Na+/K+ ATPase pump.
**Option B:** Lidocaine is ineffective in digoxin-induced arrhythmias due to its mechanism of sodium channel blockade, which may paradoxically increase toxicity.
**Option C:** Potassium administration is contraindicated in hypokalemia-induced digoxin toxicity, as it can exacerbate cardiac depression and arrhythmias.

**Clinical Pearl / High-Yield Fact** DigiFab is the only antidote for life-threatening digoxin toxicity. Avoid calcium and use potassium cautiously—always check serum K+ levels first. Remember: "Digoxin toxicity, DigiFab to rescue."

**Correct Answer: C. Digoxin immune Fab (DigiFab)**

✓ Correct Answer: B. Lignocaine