Which one of the following best represents the mechanism of action and electrocardiographic effect of diltiazem?
Flecainide is a Class Ic antiarrhythmic agent and is a potent sodium channel blocker that slows ventricular conduction and increases QRS duration. Diltiazem is a calcium channel blocker similar to verapamil and acts to slow atrioventricular conduction and increase the PR interval. Esmolol is a sho-acting l3-adrenergic receptor blocker that also slows atrioventricular conduction and increases the PR interval. Sotalol is a Class III antiarrhythmic agent that also has l3-adrenergic receptor blocking activity. It blocks potassium channels and thereby slows repolarization and increases the QT interval. Ref: katzung 12th ed, cardiovascular system
Calcium channel blockade; increased QT interval
Adrenergic receptor blockade; decreased QT interval
Calcium channel blockade; increased PR interval
Potassium channel blockade; increased QRS duration
Cardiovascular system