Rhythm and Rate Management
Antiarrhythmic Medication
Medication is one of several ways to manage heart rhythm disorders. It may be used to control the heart rate, to help maintain a normal rhythm, or alongside procedures such as catheter ablation, cardioversion and device therapy.
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Overview
What Is Antiarrhythmic Medication?
Antiarrhythmic medication is a broad term for medicines that influence the heart’s rate or rhythm. Some slow the heart, some make an abnormal rhythm less likely to start or continue, and some are used in hospital to stop an episode that is already under way.
Medication is one of the main treatment options alongside catheter ablation, electrical cardioversion and device therapy.
Not every rhythm disorder needs a medicine, and not every medicine suits every person. In some conditions observation is enough. In others a medicine, a procedure, a device or a combination is chosen.
This page gives a general overview only. It cannot replace the advice of your own doctor, and you should never start, stop or change a medicine without medical advice.
Indications
When Medication May Be Considered
To ease symptoms
Palpitations, breathlessness or tiredness during a fast rhythm may improve when the rate or rhythm is brought under better control.
To control the heart rate
In conditions such as atrial fibrillation, the lower chambers can respond too quickly. Slowing the rate can reduce symptoms and strain on the heart.
To help keep a normal rhythm
Some medicines make it less likely that an arrhythmia returns after it has stopped, or after cardioversion.
To stop an episode
Certain medicines are given in hospital to end a fast rhythm. Which one is suitable depends on the rhythm and the person.
To bridge to a procedure
Medication may be used while tests are completed, or before an ablation, cardioversion or device is planned.
As part of a wider plan
In some inherited or structural heart conditions, medicines form part of a plan that may also include lifestyle advice, monitoring, devices or procedures.
Strategy
Rate Control and Rhythm Control
Rate control aims to keep the heartbeat within a comfortable range even if the underlying rhythm remains abnormal. It is commonly discussed in atrial fibrillation and atrial flutter.
Medicines that act on conduction through the AV node are often used for this purpose.
Rhythm control aims to restore and maintain a normal rhythm. It can involve medicines, electrical cardioversion, catheter ablation, or a combination.
Which strategy suits a person depends on symptoms, the type of rhythm disorder, how long it has been present, heart structure and other health conditions. The strategy can change over time. See Atrial Fibrillation.
Groups
Medication Groups at a General Level
Beta-blockers
Slow the heart rate and reduce the effect of adrenaline on the heart. They are used for rate control, for some tachycardias and in several inherited or structural conditions.
Calcium channel blockers (non-dihydropyridine)
Slow conduction through the AV node. They are used to control the rate in some supraventricular rhythms and are not suitable for every rhythm or every heart condition.
Sodium-channel blocking medicines
Slow the speed of electrical conduction in heart muscle. They are used in selected patients to maintain a normal rhythm and are not suitable for people with certain structural heart conditions, which is why assessment comes first.
Potassium-channel blocking medicines
Lengthen the time heart cells take to recover electrically. They are used for rhythm control in selected atrial and ventricular conditions. Some affect the QT interval on the ECG and need monitoring.
Digitalis-type medicines
Slow conduction at the AV node and may be used for rate control in selected patients.
Medicines for specific situations
Intravenous medicines used in hospital to end an episode, and medicines used in particular inherited conditions, are chosen individually.
This list is general. It does not cover every medicine, and it is not a guide to what any individual should take. Choice, combinations and suitability are decided by your doctor.
Individual choice
Why the Choice Depends on the Person
The same medicine can be helpful in one rhythm disorder and unsuitable in another. The decision takes into account:
- the exact rhythm and its mechanism
- heart structure and pumping function
- coronary artery disease and valve disease
- kidney, liver and thyroid function
- other medicines, because of possible interactions
- ECG measurements such as the QT interval
- age, pregnancy or plans for pregnancy, and daily activities
Because of this, a recorded rhythm, an ECG, an echocardiogram and blood tests often come before treatment. See Electrocardiography and Holter Monitoring.
When a rhythm has a defined mechanism, as in AVNRT or WPW syndrome, a medicine may be used while a procedure that targets the cause is considered.
Medication and procedures
Before, Instead of, or Alongside a Procedure
In selected patients medication is tried first. Examples include mild or infrequent symptoms, a preference to start with medicines, or a period of further testing.
Medication may also continue instead of a procedure when a procedure is not suitable or is not wanted.
Medication may be used alongside a procedure when the two work together, for example after catheter ablation or cardioversion, or together with an implantable defibrillator.
Plans are reviewed over time. A medicine that was needed early after a procedure may later be reduced or stopped on medical advice.
Safety
Monitoring, Side Effects and Safety
Monitoring
Some medicines need ECG checks, blood tests, or review of kidney, liver or thyroid function. The schedule depends on the medicine and the person. Follow-up matters even when you feel well.
Possible side effects
Tiredness, a slow pulse, dizziness or low blood pressure can occur with some medicines. Report symptoms to your care team rather than stopping treatment on your own.
Proarrhythmic effects
Occasionally, a medicine intended to prevent arrhythmias can itself provoke a new or worse rhythm disturbance. This is one reason medicines are chosen carefully, are sometimes started under monitoring, and are reviewed regularly.
Interactions
Other prescribed medicines, herbal products and some supplements can change how an antiarrhythmic medicine works. Tell your care team about everything you take.
Pregnancy and planning
Some medicines are not suitable during pregnancy. Discuss plans with your doctor before conception.
Seek urgent medical help for fainting, chest pain, severe breathlessness, or a very fast or very slow heartbeat.
Limits
When Medication May Not Be Enough
A medicine may not fully control a rhythm, may work less well over time, or may cause effects that are hard to tolerate. In some conditions a procedure or a device addresses the cause or the risk more directly.
The options can then include a different medicine, electrical cardioversion, catheter ablation, or a device such as a pacemaker or an implantable defibrillator.
A change of plan does not mean that treatment has failed. It reflects that treatment is adjusted as more information becomes available.
Relationship to ablation
Medication and Catheter Ablation
Catheter ablation treats the electrical source or pathway of an arrhythmia, whereas medication acts on the electrical behaviour of the heart more broadly. Neither is better in every situation. The balance depends on the rhythm disorder, symptoms, earlier treatment and personal preference.
Medication is often continued for a period after ablation and may be adjusted or stopped later according to the result. See Catheter Ablation, Atrial Fibrillation Ablation and Treatments.
Atrial fibrillation
Medication and Stroke Prevention in AF
In atrial fibrillation, medicines that control the rate or rhythm are separate from anticoagulants (blood thinners). Anticoagulants do not control the heartbeat. They lower the risk of clots that can cause stroke.
The decision to use an anticoagulant is based on individual stroke risk, not on how the rhythm feels, and it usually continues even when the rhythm is well controlled or after a procedure. Bleeding risk is assessed too. Never stop an anticoagulant without advice. See Atrial Fibrillation and Left Atrial Appendage Closure.
Questions
Frequently Asked Questions
Is medication the same as treating the cause of the arrhythmia?
Will I need to take medication for life?
Can I stop a medicine when I feel well?
Do I need an electrophysiology study before starting medication?
Can medicines cure an arrhythmia?
Can antiarrhythmic medicines cause arrhythmias?
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