The EKG in the patient treated with calcium channel blockers

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

1. In patients with sinus node disease, verapamil and diltiazem may cause severe bradycardia and even sinus arrest.
2. Effect on rate depends on the balance between the effect on the conduction system and a reflex increase in the heart rate due to vasodilation.
3. Diltiazem and verapamil may prolong the PR interval, nifedipine has no effect.
4. No effect on the QRS or the QTc

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