Medications for an irregular heartbeat — known as arrhythmia — aim to treat symptoms and prevent damage to a person’s heart and other organs. Depending on the type of arrhythmia, medication can help slow or regulate a person’s heartbeat.

Arrhythmias affect 1.5–5% of the population, and there are several types. Among them, atrial fibrillation is the most common.

A wide range of medications is available to treat arrhythmias. People must consult healthcare professionals and undergo treatment to prevent arrhythmias from worsening.

This article discusses arrhythmias and the best medications for treating them.

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An irregular heartbeat, or arrhythmia, is a condition where the rhythm of the heart is not working correctly.

According to the National Heart, Blood, and Lung Institute (NHLBI), arrhythmias occur due to issues in the electrical signals within the heart, which helps control the rate of heartbeat.

The heart may beat too slowly, too quickly, or irregularly. Types of arrhythmia include:

  • Tachycardia: The heart beats faster than 100 beats per minute.
  • Bradycardia: The heart beats slower than 60 beats per minute.
  • Premature heartbeat: The signal comes earlier, causing the heart to skip a beat.
  • Atrial flutter: The upper chambers of the heart — the atrial — beat faster than the ventricle, the lower chambers of the heart.
  • Atrial fibrillation: The heart beats much faster than expected, causing inadequate pumping of blood to the lungs and the entire body. This is the most common type of arrhythmia.
  • Paroxysmal supraventricular tachycardia (PSVT): Issues with the electrical signal that leads to extra heartbeats. In most cases, it begins and ends suddenly and occurs commonly in young people.
  • Ventricular tachycardia: The ventricles beat too fast and might last for a few seconds or longer. Ventricular tachycardia that lasts more than a few seconds can increase the risk of ventricular fibrillation.
  • Ventricular fibrillation: This occurs if the electric signals cause the quivering of ventricles instead of the usual pumping of blood. This can result in sudden cardiac arrest and death.

Most cases of arrhythmia are treatable with medication or procedures. However, if left untreated, they can damage the heart, brain, and other organs. This can lead to cardiac arrest, heart failure, or stroke.

According to the NHLBI, people with an irregular heartbeat may need one or more medications alongside other treatments.

People must consult a healthcare professional to undergo accurate diagnosis and to understand the type and severity of arrhythmia. Doctors prescribe appropriate medications based on these factors.

Some common medications to treat arrhythmia and their side effects are detailed below.

Beta-blockers

Beta-blockers are a class of medication that binds to specific beta receptors and blocks the action of hormones such as adrenaline.

They help to slow down the heart rate and are approved by the Food and Drug Administration (FDA) to treat tachycardia and cardiac arrhythmias. Beta-blockers also help lower blood pressure, reducing the risk of heart attacks.

Examples

Common types of beta-blockers include:

Dosage

Beta-blockers are available in intravenous or oral forms. Dosage is often twice daily, but certain types can be 3–4 times per day.

Side effects

Common side effects of beta-blockers are bradycardia and hypotension (low blood pressure). Other common side effects may include:

People should follow the dosages recommended by a healthcare professional and check the drug packet for more information on potential side effects.

Sodium channel blockers

Sodium channel blockers bind to the sodium channels of the heart. Sodium channels are responsible for the conduction of an electric impulse through the heart and help coordinate its conduction system.

Blocking the sodium channels can decrease the rate of transmission of an electric impulse. This makes them effective in treating ventricular tachycardia, atrial fibrillation, and flutter.

Examples

Common types of sodium channel blockers are:

  • quinidine
  • lidocaine
  • disopyramide
  • procainamide

Dosage

People can take sodium channel blockers orally or intravenously. The dosage varies depending on the type of sodium channel blocker.

Side effects

Side effects tend to be drug-specific. For example, side effects of quinine may include:

People should follow the dosages recommended by their healthcare professionals and check the drug packet for more information on potential side effects.

Potassium channel blockers

Potassium channel blockers are drugs that bind to potassium channels, which help with the flow of potassium ions in the heart. The flow of potassium ions results in rapid repolarization of the cells.

The blocking of potassium channels delays the repolarization of cells, thereby resulting in QT prolongation — a process that slows the heart’s contractions. These drugs help treat atrial fibrillation, flutter, and ventricular tachycardia.

Examples

Common examples of potassium channel blockers are amiodarone and dofetilide.

Dosage

Administration of potassium channel blockers takes place orally or intravenously. Their dosage varies depending on the type of administration pathway.

Side effects

The use of potassium channel blockers can increase the risk of:

  • other types of arrhythmia
  • vision disturbances
  • lung disease
  • thyroid level issues

Calcium channel blockers

Calcium channel blockers bind to calcium channels of the heart and block the inward flow of calcium ions.

They help treat arrhythmias by slowing the heart rate and lowering blood pressure.

Examples

Common examples of calcium channel blockers are:

Dosage

Administration of calcium channel blockers takes place orally or intravenously. However, the dosage varies depending on the severity of the symptoms.

Side effects

Side effects of calcium channel blockers may include:

Healthcare professionals may prescribe anticoagulant medication if an arrhythmia, in particular atrial fibrillation, puts a person at risk of clots or stroke from clots.

Anticoagulants are blood-thinning medications that work to reduce the risk of the formation of future blood clots by changing the composition of blood.

Examples of anticoagulants approved for people with atrial fibrillation include:

Learn more about medications for atrial fibrillation.

Some people with arrhythmias develop severe symptoms and complications that can lead to cardiac arrest.

People usually need to take medications if they display the following serious symptoms:

People must keep track of their symptoms and immediately consult a doctor if they become severe.

Factors that increase the risk for arrhythmias are:

Medications for arrhythmia can interact with other medications along with herbal or vitamin supplements. For example, people must avoid grapefruit juice while taking these medications as it can increase their toxicity.

People must inform a doctor if they are taking any of the following drugs to avoid adverse effects:

  • medications that treat high blood pressure
  • medications that treat diabetes
  • medications that treat chronic pulmonary diseases or asthma
  • other medications that treat irregular heartbeats
  • medications that treat allergies, such as adrenaline or noradrenaline
  • nonsteroidal anti-inflammatory medications (NSAIDs)
  • medications that treat certain mental health conditions

Other treatment options for arrhythmias include:

  • Cardioversion: A procedure that utilizes external electric shocks to restore the usual heart rhythm.
  • Catheter ablation: A technique to stop the transmission of incorrect electrical impulses through the heart that leads to irregular heartbeats.
  • Implantable cardioverter defibrillators (ICDs): Devices that can send an electric pulse or shock to the heart to restore a regular heartbeat.
  • Pacemaker: A small device that sends electrical pulses to ensure that the heart chambers beat together in sync.
  • Vagal maneuvers: Relaxation techniques that can help slow the heart rate. Methods include placing a towel soaked in ice water over the face, lying down, and coughing.

People must seek emergency medical care if their heart rate is too fast, too slow, or beating irregularly, alongside chest pain, dizziness, and shortness of breath.

People must also have check-ups while undergoing treatment for arrhythmias to ensure proper intake of medications and evaluation of any implanted devices.

Family and friends of people with arrhythmias can also learn cardiopulmonary resuscitation (CPR) in case of emergencies.

Arrhythmias are common and result in an irregular heartbeat. Several medications are available, depending on the type and severity of arrhythmia.

People experiencing symptoms of an irregular heartbeat must consult a healthcare professional for proper diagnosis and treatment. This is important since certain cases of untreated arrhythmia can cause cardiac arrest and death.