Allergy to class/drug
Significant QRS widening
High Grade Heart Block
Heart Failure
Left Ventricular Dysfunction
Bradycardia
Cardiogenic Shock
Electrolyte Imbalance
Hypotension
Sick Sinus Syndrome
Long QT Syndrome
Brugada Syndrome
Renal failure (relative)
Hepatic failure (relative)
Asthma
COPD
Bronchospasm
SLE
Propafenone
Verapamil
Amiodarone
Flecainide
Lofexidine
Procainamide
Sotalol
Ibutilide