Normal electrical conduction refers to the normal passage of electricity through the heart tissue. Electricity typically originates in the sinus node in the top right corner of the heart. From there, it is transmitted through both the left and right atrium, and then passes through the AV node in the middle of the heart. The AV node transmits the electricity into the ventricles. As electricity moves through the ventricles, the ventricles contract, thereby pumping blood to the lungs and body.
Arrhythmia Definition
The term arrhythmia means an abnormal heart rhythm. An arrhythmia generally refers to any abnormality in the way electricity moves through the heart. It can include both faster than normal heart rhythms (tachycardia), as well as slower than normal heart rhythms (bradycardia).
Arrhythmia Causes
There are a number of different types or causes of arrhythmias in children. One of the most common arrhythmias found in children is supraventricular tachycardia (SVT). With SVT, there is usually an extra conducting pathway from the atria to the ventricles. The presence of an extra conducting pathway can allow for a circuit to be set up between the extra pathway and the normal AV node. This may result in a much faster than normal heart rate, called supraventricular tachycardia. Wolff-Parkinson-White syndrome (WPW), is one form of supraventricular tachycardia.
Less common arrhythmias found in children include atrial tachycardia, atrial flutter, and very rarely atrial fibrillation. Ventricular tachycardia may also occur in children, although it is much less common than seen in adults.
Arrhythmias resulting in slow heart rhythms include forms of AV block, including complete heart block. In addition, premature atrial contractions and premature ventricular contractions are also commonly classified as arrhythmias.
Arrhythmia Symptoms
Arrhythmia symptoms vary quite a bit based on the underlying cause of the arrhythmia. Children with arrhythmias resulting in a slow heart rate may have symptoms of lightheadedness, syncope, chronic fatigue, or exercise intolerance. Children with arrhythmias resulting in a faster than normal heart rate may have symptoms of palpitations as well as dizziness and rarely syncope.
Arrhythmia Treatment
Fortunately most arrhythmias in children are treatable with either medication or procedures to eliminate them. A cardiac catheterization, electrophysiology study and radiofrequency ablation may occasionally be necessary.