Sat, May 12, 2012

Junctional Tachycardia

Junctional tachycardia is an uncommon arrhythmia that can be found in both babies and older children.

What is junctional tachycardia?

Junctional tachycardia (or junctional ectopic tachycardia or JET) is an arrhythmia, or an abnormal heart rhythm that causes a fast heart rate in children. Normal electrical conduction in the heart starts with the generation of electricity in the sinus node in the upper portion of the right atrium. Electricity moves from the sinus node through the atrium. From there, it is transmitted to the AV node to the ventricles. As electricity passes to the ventricles, the heart muscle contracts.

What causes junctional tachycardia in children?

Tachycardia means a faster than normal heart rate. Junctional tachycardia is a specific type of tachycardia that involves the specialized conducting tissue in and around the AV node and its associated structures. With junctional tachycardia, electricity is fired from a source very close to the AV node at a very fast rate. In babies, junctional tachycardia may be as fast as 250-350 beats per minute. In older children and teenagers, the heart rate is often in the range of 180-250 beats per minute.

Junctional tachycardia is seen most commonly following open heart surgery in children. In this setting, it is usually caused by inflammation and swelling of the tissue near the AV node. This irritation causes the tissue to fire electricity at a much faster than normal rate. Because the heart is already under stress related to the preceding heart surgery, the complication of junctional tachycardia can be fairly dangerous. Treatment is usually initiated very quickly with the goal of keeping the heart rate at a reasonably slow level. Fortunately junctional tachycardia in this setting is a self-limited arrhythmia that usually resolves on its own after a few days. Treatment beyond the patient's normal hospital stay is typically unnecessary.

When junctional ectopic tachycardia develops in a baby, it is termed congenital junctional tachycardia, or congenital JET. This can be a very dangerous and difficult to treat arrhythmia. In many instances it may require several different anti-arrhythmic medications. Infants with congenital JET are at high risk for developing congestive heart failure. In some cases it may be fatal. Fortunately it is extremely rare.

Where the signs and symptoms of junctional tachycardia in children?

The danger of junctional tachycardia, or any tachycardia for that matter, involves the degree of stress placed on the heart muscle. When the heart rate is very fast, or even when the heart rate is not so fast but continues at a high rate for a prolonged period of time, the heart muscle tires out. This may lead to ineffective pumping and the development of congestive heart failure.

Babies with junctional tachycardia may have no symptoms at all. The problem is often detected when a faster than normal heart rate is heard during a routine examination. If the problem has gone on long enough, symptoms of heart failure may result. In an infant, these include rapid breathing, sweating, irritability, poor feeding, and poor weight gain.

Older children with junctional tachycardia often experience palpitations. They typically complain of their heart racing. Symptoms of congestive heart failure in older children with junctional tachycardia are uncommon.

How is junctional tachycardia in children treated?

In older children who developed junctional tachycardia after open heart surgery, intravenous medication is usually required. Fortunately junctional tachycardia in this setting is usually self-limited. Most children does not require long-term treatment.

Babies with junctional tachycardia may become very ill because of the persistently elevated heart rate. Medication therapy is almost always required. In many cases, more than one medicine may be necessary. In some instances it may be impossible to completely eliminate the arrhythmia; in this situation the goal is simply to achieve a relatively slower heart rate. Rarely an infant with junctional tachycardia may require an invasive procedure to cure the problem. Fortunately most cases of junctional tachycardia can be controlled with medication.