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Antiarrhythmic Therapy
Basic Facts
An arrhythmia is an abnormality or disturbance in the rate or rhythm of a person's heartbeat.
Antiarrhythmic drug treatment is designed to suppress arrhythmias by treating the underlying cause of arrhythmias, to prevent conditions that contribute to arrhythmias, and to manage arrhythmia symptoms.
Common medications used to treat arrhythmias include a category of drugs referred to as antiarrhythmic agents, beta-blockers, calcium channel blockers, and digitalis.
An arrhythmia is a change in the heart's normal rate or rhythm. Arrhythmias are classified by their location in the heart and by their speed or rhythm. An atrial or supraventricular arrhythmia is a rhythm abnormality that occurs in one of the two upper chambers of the heart, the left or right atrium. Ventricular arrhythmias originate in the ventricles and can interfere with the heart's ability to pump blood to the body. They are potentially dangerous arrhythmias, but in some circumstances, especially in the absence of structural heart disease, they can be benign.

When an arrhythmia occurs repeatedly over time or causes symptoms such as palpitations, lightheadedness, fainting (syncope), shortness of breath, or chest pain, it may require treatment.


Once the physician has recorded an arrhythmia and established its location in the heart, he or she can decide if treatment is necessary, and, if so, which treatment option is most appropriate. When treating arrhythmias, physicians consider if an underlying heart problem such as heart disease, past heart attack, or valve disease is contributing to an arrhythmia. Physicians also evaluate conditions such as ischemia (lack of oxygen to the heart) or electrolyte or metabolic abnormalities, which may affect any underlying heart problem, and determine if the patient prefers drug therapy or other treatment approaches.

For purposes of treatment, physicians use two classifications of arrhythmias: ambient, or triggering, arrhythmias, and sustained arrhythmias.

Triggering arrhythmias include premature atrial contractions (PACs) and premature ventricular complexes (PVCs).

Sustained arrhythmias include:
  • Atrial fibrillation;
  • Supraventricular tachycardia;
  • Ventricular tachycardia; and
  • Ventricular fibrillation.
The goals of antiarrhythmic treatment are to prevent or suppress arrhythmias by treating the underlying cause of arrhythmias. Physicians also seek to prevent conditions that contribute to arrhythmias, such as ischemia and metabolic imbalances in the heart muscle, and to manage serious symptoms such as lightheadedness, shortness of breath, fatigue, and chest pain.

When medical treatment is required to suppress an atrial arrhythmia, physicians decide which drugs to use based on the risks and quality-of-life effects of the arrhythmia, the presence of any underlying disease, the severity of a person's symptoms, and the risk of side effects. Common medications include a category of drugs referred to as antiarrhythmic agents, beta-blockers, calcium channel blockers, and digitalis.

Antiarrhythmic agents: These drugs affect the electrical activity of the heart rate by slowing the conduction of impulses through heart tissue or blocking electrical impulses. Certain antiarrhythmic agents are not used in people who have congestive heart failure.

Beta-blockers: Beta-blockers block the effect of adrenaline and are effective in slowing and regularizing the heart rate.

Side effects of beta-blockers include:
  • Depression;
  • Dizziness;
  • Weakness;
  • Fatigue;
  • Lightheadedness;
  • Sexual dysfunction; and
  • Sleep disturbances.
Calcium channel blockers: Calcium channel blockers prevent calcium atoms from penetrating heart muscle tissue. This forces muscles to contract less vigorously by making them less responsive to the electrical signals that cause muscle contraction. This action also dilates (widens) blood vessels and lowers blood pressure. Calcium channel blockers also slow conduction through the atrioventricular node (A-V node), making them useful for certain types of arrhythmias.

Side effects of calcium channel blockers include:
  • Constipation;
  • Fatigue;
  • Flushing;
  • Swelling;
  • Heartburn;
  • Dizziness;
  • Nausea;
  • Low blood pressure; and
  • Headache.
Digitalis: Digitalis regulates the heart's rate and rhythm by slowing the transmission of electrical impulses from the atria to the ventricles. The drug also strengthens the force of heart contractions, which can improve circulation.

Some antiarrhythmic medications may be harmful to patients who have an implanted pacemaker, or who had or are having surgery, including dental surgery. People should also be aware that caffeine can decrease the effectiveness of antiarrhythmic medications.

In some cases, such as with arrhythmias that cannot be treated with medication, physicians may use interventional or surgical procedures to control the arrhythmia. These procedures may include:
  • Pacemaker implantation;
  • Cardiac defibrillator implantation;
  • Catheter ablation, and
  • MAZE procedure, a surgical procedure.
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