Class IV of the antiarrhythmics comprise the calcium channel blockers - verapamil but not the nifedipine group.
Verapamil should not be used for tachyarhythmias where the QRS complex is wide. Also it should not be used if there is atrial fibrillation with pre-excitation e.g. Wolff-Parkinson-White syndrome.
Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.