SVT is a rapid heart beat arising from the top chambers of the heart. There are several causes of SVT. SVT often arises from an extra circuits in the heart which is present at birth and is activated later in life. The most common circuit is in the middle of the hearts electrical system next to AV node called dual AV nodes and AVNRT (The AV node electrically joins the top chambers called atria and bottom chambers called ventricles). Extra circuits joining the top and bottom chambers of the heart may also be present on the right or left side of the heart (WPW). Finally the source can be a single focus coming from the right or left top chamber of the heart (atrial tachycardia).
The diagnosis is usually made by electrocardiogram or event monitor during an episode of SVT. To stop an acute episode vagal maneuvers such as bearing down can help. In the long termthe treatment for SVT is usually medication or an ablation. While medications can sometimes reduce the severity of the episodes they do no eliminate the extra. An ablation is a relatively low risk procedure that eliminates the extra circuit and cures the problem.
For pacemakers or defibrillators
Risks of procedure are mainly infection – if that occurs, the entire system must be removed, injury to the lung requiring placement of a chest tube for 1-2 days, injury to the heart muscle or lead dislodgement requiring repositioning. The risk of any of these is less than 1 percent.
The risk of SVT ablation or VT ablation is injury to a vein in the groin which can require local surgery, injury to the heart muscle or ending up needing a pacemaker. The risk of any of these is well below 1 percent.