Palpitations

How Are Palpitations Treated?

In most people, palpitations do not indicate underlying heart disease, and treatment other than reassurance or lifestyle changes is not needed. In some cases, your doctor may discover that your palpitations are due to an arrhythmia (irregular heartbeat) that warrants medical treatment. Several types of treatments are available for palpitations caused by problems with heart rate or heart rhythm.

Common Medications

The basic treatment for the management of most important arrhythmias are medications called “antiarrhythmics.” These agents are generally classified according to their mechanism of action. There are four classes of these medications:

• Class I antiarrhythmic drugs, known as “sodium channel blockers.” These medications have long been used in the United States to control arrhythmias. They work by blocking “sodium channels” (the transport of sodium across the cell walls) in order to slow impulse conduction in the heart.

  But these agents can also depress function in the left ventricle (reduce effectiveness of pumping) and aggravate or promote arrhythmias. Some of these induced arrhythmias are serious, so these drugs should always be used with caution.

• Class II antiarrhythmic drugs, known as “beta-blockers.” These medications slow the heart rate and force of contraction by decreasing the sensitivity of cells to adrenaline and adrenaline-like substances that act at beta receptors. Beta-blockers have long been used to control supraventricular tachycardias (SVTs), and recent evidence suggests they may be helpful in suppressing ventricular tachycardia and ventricular fibrillation.

  Although beta-blockers can also cause bradycardia, these induced arrhythmias are generally not serious. Other side effects of beta-blockers include left ventricular depression, fatigue, and stomach upset. Beta-blockers are also used to treat high blood pressure and angina (chest pain that occurs when the arteries do not supply enough blood to the heart). They are commonly used after a heart attack.

• Class III antiarrhythmic drugs, known as “potassium channel blockers.” They work, in part, by prolonging the recovery time of cardiac cells after they have carried an impulse. This can prevent circuits (electrical pathways) from causing an arrhythmia or only permit slower arrhythmias.

• Class IV antiarrhythmic drugs, known as “calcium channel blockers.” These medications slow the heart rate by blocking heart cells’ calcium channels (transport of calcium across the cell walls) and slowing conduction at the AV node.

  In addition to slowing the heart rate, these medications dilate (open up) blood vessels and decrease the force of cardiac contraction. Like beta-blockers, calcium channel blockers are used to control some forms of SVT and ventricular tachycardia and to slow the ventricular rate in people with atrial fibrillation.

Other Medications

In addition to the above four classes of antiarrhythmic drugs, there are also some miscellaneous drugs:

• Digoxin – This medication increases the strength of heart muscle contractions and is useful in the treatment of heart failure. Because digoxin also slows conduction through the AV node, it may be useful in controlling atrial fibrillation, atrial flutter, and atrial tachycardia. It often is combined with beta- or calcium-channel blockers.
• Adenosine – This drug slows or blocks conduction through the AV node by acting on special adenosine receptors. Since adenosine is only available in intravenous form and only works for a short time, it is only used as acute treatment for supraventricular tachycardias.

Pacemakers

A pacemaker is a disk that weighs less than two ounces. It consists of a pulse generator (pacemaker) containing a battery and electronic circuitry, as well as one or more pacing wires (leads) that connect the pacemaker to the heart. The battery can last for 5 to 10 years and can be replaced when necessary.

The pacemaker is generally implanted under the skin, just beneath the collarbone. Most people go home the same day following the implant, but some need an overnight hospital stay.

Artificial pacemakers are the most commonly used treatment for a slow heart rate (bradycardia). Pacemakers work by sensing electrical signals from the heart and sending out electrical impulses for a slow heart rate, to cause the heart to beat if the heart does not generate an electrical impulse after a certain period of time.

Pacemakers for a fast heartbeat also exist. These implantable pacemakers are about the size of conventional pacemakers and are used to automatically stop certain fast arrhythmias.

Electrical Cardioversion And Defibrillation

In cardioversion, an electric shock is delivered to the heart to stop an abnormal rhythm and allow a normal rhythm to resume. This shock is applied through two paddles on the chest, or one on the chest and one on the back. The electric shock interrupts the heartbeat for a brief moment. This resets the heart’s electrical control system and can return the heart to a normal rhythm.

Cardioversion is used to stop all life-threatening tachycardias. The conversion of ventricular fibrillation to sinus rhythm is referred to as defibrillation. Cardioversion is also useful for stopping supraventricular tachycardias such as atrial flutter or atrial fibrillation.

Radiofrequency (Catheter) Ablation

Radiofrequency (catheter) ablation refers to the destruction of small portions of electrical pathways in the heart using long, thin, plastic-coated wires (catheters). This catheters are threaded through the blood vessels to the heart, much like the cardiac catheterization procedure described earlier. The circuit is then “mapped” by using x-ray to direct the wires and then analyzing the pathway of the heart’s electrical signals transmitted by the wire to locate the circuit.

After the circuit has been mapped, electrical energy is delivered to the tip of the wire. This energy causes a small burn at the site of the catheter tip, which destroys the circuit. This technique has revolutionized the treatment of many arrhythmias and is considered to be quite safe.

Implantable Cardioverter-Defibrillators (ICDs)

For some individuals (such as those with frequent, poorly controlled ventricular tachycardia, or people with a history of resuscitated sudden death), a small automatic device can be surgically implanted under the collarbone to deliver an electric shock to the heart if a serious arrhythmia is detected. Such a system is referred to as an implantable cardioverter-defibrillator, or ICD. As these systems do not prevent arrhythmias, they are combined with other therapy that suppresses arrhythmias.