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What is Quinidine exes action on hea by and explain in detail?
Refer katzung 11e p 237 * Mechanism of action Like all other class I antiarrhythmic agents, quinidine primarily works by blocking the fast inward sodium current (INa). ... The effect of blocking the fast inward sodium current causes the phase 0 depolarization of the cardiac action potential to decrease (decreased Vmax).