The heart’s job is to pump blood through your body. The heart’s electrical system triggers the heart to pump. The pulse or heartbeat is what you feel when the heart’s lower chambers, ventricles, push blood out of the heart through the blood vessels.
The normal heart beat is regular (no skipping), and has a rate between 60 to 100 beats per minute. When you rest your heart rate slows down, when you are active your heart rate goes up.
The Heart’s Electrical System
The electrical signal starts in the heart’s right upper chamber (the right atrium) at the sinus node and then spreads to the other upper chamber (the left atrium). The signal is then collected at the center of the heart at the AV node. The AV node is the only electrical connection from the upper chambers (atria) to the lower chambers (ventricles) in the normal heart. From the AV node, the signal speeds along special nerves call the right and left bundle branches into the lower chambers (the ventricles). The electrical signal triggers the ventricles to pump blood to the body.
What is SVT?
The word supraventricular tachycardia mean; supra (above), ventricular (lower heart chamber) and tachycardia (rapid heart rate). This means the arrhythmia primarily involves the upper heart chambers. The electrical signal starts with a premature beat that gets “recycled” through an electrical loop at the AV node or another path. This can happen with no warning and the fast heartbeat can cause shortness of breath, lightheadedness and anxiety.
The “recycling” of the electrical signal at the AV node is called AV node reentry tachycardia. The “recycling” of the electrical signal though another path can be Wolff-Parkinson-White tachycardia.