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By Medifit Education



Antiarrhythmic 1


Preventing or alleviating irregularities in the force or rhythm of the heart. An antiarrhythmic substance, such as lidocaine.



Antiarrhythmics are drugs that are used to treat abnormal heart rhythms resulting from irregular electrical activity of the heart. There are many different types of antiarrhythmic drugs.

Antiarrhythmics are drugs that are used to treat abnormal heart rhythms resulting from irregular electrical activity of the heart. There are many different types of antiarrhythmic drugs.

Examples include: Tambocor (flecainide)


Some of the major types of commonly prescribed cardiovascular medications are summarized in this section. For your information and reference, we have included generic names as well as major trade names to help you identify what you may be taking; however, the AHA is not recommending or endorsing any specific products. If your prescription medication isn’t on this list, remember that your healthcare provider and pharmacist are your best sources of information. It’s important to discuss all of the drugs you take with your doctor and understand their desired effects and possible side effects. Never stop taking a medication and never change your dose or frequency without first consulting your doctor.


  • Worsening arrhythmias.
  • Allergic reaction.
  • Chest pain.
  • Fainting.
  • Swelling of the feet or legs.
  • Blurred vision.
  • Shortness of breath.

With beta-blockers as the exception, increasing doubt is emerging on the value of antiarrhythmic drug therapy following a series of trials that have either shown no mortality benefit or even an excess mortality. Vaughan Williams class I drugs are generally avoided in patients with structural heart disease, and class IV drugs are avoided in heart failure. Unfortunately, arrhythmias are a growing problem due to an increase in the incidence of atrial fibrillation and sudden death. The population is becoming older and more patients survive for a longer time period with congestive heart failure, which again increases the frequency of both supraventricular as well as ventricular arrhythmias. Class III antiarrhythmic drugs act by blocking repolarising currents and thereby prolong the effective refractory period of the myocardium. This is believed to facilitate termination of re-entry tachyarrhythmias. This class of drugs is developed for treatment of both supraventricular and ventricular arrhythmias. Amiodarone, sotalol, dofetilide, and ibutilide are examples of class III drugs that are currently available. Amiodarone and sotalol have other antiarrhythmic properties in addition to pure class III action, which differentiates them from the others. However, all have potential serious adverse events. Proarrhythmia, especially torsade de pointes, is a common problem making the benefit-risk ratio of these drugs a key question. Class III drugs have been evaluated in different settings: primary and secondary prevention of ventricular arrhythmias and in treatment of atrial fibrillation or flutter. Based on existing evidence there is no routine indication for antiarrhythmic drug therapy other than beta-blockers in patients at high risk of sudden death. Subgroup analyses of trials with amiodarone and dofetilide suggest that patients with atrial fibrillation may have a mortality reduction with these drugs. However, this needs to be tested in a prospective trial. Similarly, subgroups that will benefit from prophylactic treatment with class III antiarrhythmic drugs may be found based on QT-intervals or – in the future – from genetic testing. Class III drugs are effective in converting atrial fibrillation to sinus rhythm and for the maintenance of sinus rhythm after conversion. This is currently by far the most important indication for this class of drugs. As defined by recent guidelines, amiodarone and dofetilide have their place as second-line therapy except for patients with heart failure where they are first line therapy being the only drugs where the safety has been documented for this group of high risk patients.

Antiarrhythmic 2

By Medifit Education