Anatomy All of the following statements are true about quinidine except: A It blocks myocardial Na+ channels primarily in the open state B It has no effect on myocardial K+ channels C It produces frequency dependent blockade of myocardial Na+ channels D It delays recovery of myocardial Na+ channels 💡 Explanation All of the following statements are true about quinidine except: ✓ Correct Answer: B. It has no effect on myocardial K+ channels