Clinical conditions modifying choice of antiarrhythmic agents
| Clinical condition | Treatments to consider | Contraindicated or undesirable treatments |
| Arrhythmias | ||
| Torsades de pointes |
Acute: Magnesium Isoproterenol Pacing Raise serum K+ Chronic QT prolongation: β Blockers Pacing |
QT prolonging drugs: Quinidine Procainamide Disopyramide Sotalol Ibutilide Dofetilide ???Amiodarone |
| Polymorphic VT with short QT intervals | Anti-ischaemic intervention Intravenous amiodarone | Lidocaine, procainamide (ineffective) |
| Sustained monomorphic VT | IV procainamide or sotalol | Lidocaine (ineffective) |
| RV outflow tract VT, fascicular VT | Verapamil β Blocker Adenosine (acutely) | |
| QT interval prolongation | Flecainide Propafenone Lidocaine Mexiletine ???Amiodarone | Quinidine Orocainamide Disopyramide Sotalol Ibutilide Dofetilide ???Amiodarone |
| Atrial fibrillation + structural heart disease | Flecainide | |
| Atrial fibrillation with rapid ventricular rate and pre-excitation | IV procainamide cardioversion | Verapamil Adenosine Digitalis |
| Other concomitant conditions | ||
| Heart failure | Digitalis Also acceptable: Amiodarone Dofetilide Quinidine | Diltiazem, verapamil β Blockers if severe Flecainide Disopyramide |
| Sinus/AV nodal disease | All drugs discussed have the potential to worsen bradyarrhythmias, particularly: Diltiazem, verapamil β Blockers Digitalis Amiodarone | |
| Diffuse conduction system disease | Above + most other antiarrhythmics | |
| Chronic lung disease | Amiodarone | |
| Inflammatory arthritis | Procainamide | |
| Chronic bowel disease | Quinidine (exacerbates diarrhoea) Verapamil, disopyramide (exacerbate constipation) | |
| Asthma | β Blockers Propafenone | |
| Tremor | Lidocaine Mexiletine | |
This table is not meant to supplant discussions of treatments of choice for various arrhythmia syndromes outlined in other parts of this series. Rather, specific clinical conditions which may dictate an unusual or specific choice of drugs are presented.
IV, intravenous.