Quinidine n. : An alkaloid isomeric with, and resembling, quinine, found in certain species of cinchona, from which it is extracted as a bitter white crystalline substance; conchinine. It is used somewhat as a febrifuge.

Example:
Quinidine is more effective than procainamide for?

Taxonomy
quinidine gluconate, yl, methanol, free encyclopedia, inward, Side effects, heart rates, inhibitor, Antiarrhythmic agents, the block, depolarization, ECG, drugs, symptoms, treatment, AJ, quinine, cardiac action potential.

Defination from the web:
Quinidine is a pharmaceutical agent that acts as a class I antiarrhythmic agent (Ia) in the heart. ... Quinidine also blocks the slowly inactivating tetrodotoxin-sensitive Na current, the slow inward calcium current (ICa), the rapid (IKr) and slow ...