Antiarrhythmic treatments

Antiarrhythmic drugs work by regulating the heart’s electrical activity through various mechanisms:

• They modify the function of ion channels in heart cells
• They can slow down the conduction of electrical impulses
• They can prolong the refractory period (the time during which heart cells cannot be stimulated again)
• Some act on the autonomic nervous system, which influences heart rate

These different actions help control or prevent episodes of arrhythmia, thereby reducing symptoms such as palpitations, shortness of breath, or dizziness.

Antiarrhythmic drugs are classified according to the Vaughan Williams classification, which groups them based on their main mechanism of action:

Class I: Sodium channel blockers

• Main drugs: flecainide, propafenone, quinidine, disopyramide
• Action: slow the conduction of electrical impulses
• Common uses: atrial fibrillation, atrial flutter, supraventricular tachycardias
• Special precautions: should be avoided in patients with coronary artery disease or heart failure

Class II: Beta-blockers

• Main drugs: bisoprolol, metoprolol, atenolol, propranolol
• Action: reduce the influence of the sympathetic nervous system on the heart
• Common uses: tachycardias, extrasystoles, prevention of stress-induced arrhythmias
• Advantages: generally well tolerated and versatile (also used for hypertension and heart failure)

Class III: Potassium channel blockers

• Main drugs: amiodarone, sotalol, dronedarone
• Action: prolong the refractory period of heart cells
• Common uses: atrial fibrillation, severe ventricular arrhythmias
• Note: amiodarone is highly effective but has many long-term side effects

Class IV: Calcium channel blockers

• Main drugs: verapamil, diltiazem
• Action: slow conduction at the atrioventricular node
• Common uses: supraventricular tachycardias, control of ventricular rate in atrial fibrillation

Some medications have multiple actions and may fall into more than one class. The choice of treatment depends on the type of arrhythmia, your overall heart condition, and any other health issues you may have.

Antiarrhythmic drugs can be used in several situations:

• Emergency treatment of an acute arrhythmia
• Preventive treatment to avoid recurrence of arrhythmias
• Symptom control in patients with frequent or bothersome arrhythmias
• As a complement to other treatments such as radiofrequency ablation
• While awaiting a procedure such as ablation or implantation of a cardiac device

Today, for many arrhythmias, radiofrequency ablation is often preferred because it offers a definitive solution without the need for lifelong medication. However, antiarrhythmic drugs remain essential in certain situations.

Antiarrhythmic drugs require special monitoring:

• They can sometimes have a paradoxical effect, worsening certain arrhythmias or causing new ones (proarrhythmic effect)
• Regular medical follow-up is necessary to adjust doses and monitor for possible side effects
• Regular tests (electrocardiogram, blood tests) may be prescribed to check treatment tolerance
• Some medications require special precautions during the initiation phase

Like all medications, antiarrhythmics can cause side effects:

Cardiac effects:

• Excessive slowing of the heart rate (bradycardia)
• Onset of other rhythm disorders (proarrhythmic effect)
• Worsening of pre-existing heart failure (especially with certain classes)

Non-cardiac effects (vary depending on the medication):

• Beta-blockers: fatigue, cold extremities, respiratory problems in asthmatic patients
• Flecainide: dizziness, visual disturbances, nausea
• Amiodarone: thyroid disorders, photosensitivity, corneal deposits, lung or liver problems during long-term treatment
• Calcium channel blockers: constipation, swelling of the lower limbs

If side effects occur, you should inform your doctor, who can adjust your treatment if necessary.

At the Rythmopôle Center, the management of heart rhythm disorders is based on a personalized approach:

• Accurate assessment of your arrhythmia through specialized tests
• Discussion of the different treatment options (medications, ablation, implantable devices)
• Selection of the most suitable treatment, taking into account your preferences and lifestyle
• Regular follow-up to evaluate treatment effectiveness and tolerance
• Close collaboration between cardiologists, electrophysiologists, and your general practitioner

Our expertise allows us to offer the optimal treatment, whether it involves an antiarrhythmic drug or a procedure such as radiofrequency ablation.