The antiarrhythmic drug which decreases both rate of depolarization (phase 0) as well as rate of repolarization of myocardial fibres is
Correct Answer: Quinidine
Description: QUINIDINE Mechanism of action:- Quinidine blocks myocardial Na+ channels in the open state--reduces automaticity and maximal rate of 0 phase depolarization in a frequency dependent manner. Prolongation of APD is due to K+ channel block, while lengthening of ERP is caused by its moderate effect on recovery of Na+ and K+ channels. At high concentrations it also inhibits L type Ca2+ channels. ECG:- Quinidine increases P-R and Q-T intervals and tends to broaden QRS complex. Changes in the shape of T wave may be seen reflecting effect on repolarization. Ref:- kd tripathi; pg num:-529
Category:
Pharmacology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now