<prompt> Mechanism of action of digitalis in atrial fibrillation isBy Causing bradycarliaNa K ATPase inhibitionIncrease in refractoriness of AV nodal tissueBy Causing bradycarlia  <response>: Ref: KDT 6ep502 Digitalis acts in CHF by inhibiting Na-K-ATPase whereas in AF, it acts by decreasing the conduction through AV node. 