Digoxin is useful in -

Ans. is 'b' i.e., Complete hea-block with CHF Digitalis has depressant action on AV node -4 it delayes the conduction through AV node by increased ERP. If paial block is present, digitals may conve it into complete block. But, if complete block is already present, digitalis cannot worsen the condition (as conduction is blocked to maximum block, i.e., complete hea block). So, in this condition digitalis can be used for hea failure. About other options In thyrotoxicosis and myocarditis there is reduced responsiveness and patient becomes more prone for digitalis induced arrhythmias. Digitalis is contraindicated in ventricular tachycardia as ventricular fibrillation may be precipitated.