Allergy to class/drug
Afib/flutter associated with accessory bypass tract, e.g. WPW, Lown-Ganong-Levine syndrome
Cardiogenic shock, hypotension, EF <30%
2nd or 3rd degree AV block, sick sinus syndrome
Verapamil
Amiodarone
Propafenone
Flecainide
Sotalol
Procainamide
Ibutilide
Encainide