Paroxysmal Supraventricular Tachycardia
What is It?
PSVT (also called PAT) is an abbreviation for “paroxysmal supraventricular tachycardia”, an intermittent heart racing or “palpitations”. It is usually related to an electrical abnormality in the heart ( “wiring problem” that one is born with. There are several types of “short-circuit” in the electrical system of the heart. PSVT can be quite troublesome and even disabling but rarely life-threatening.
A common electrical disorder is the Wolff-Parkinson-White (WPW) syndrome. Everybody has a normal electrical connection (AV node) that connects the upper and lower chambers of the heart. People with WPW have another “wire” or pathway joining the upper and lower parts of the heart. This can cause heart racing by several different means.
The other and perhaps most common cause of PSVT is called AV node or atrioventricular nodal re-entry. The AV node can develop a short-circuit so that the electrical signal can get “trapped” racing in a loop around the AV node.
Since PSVT is rarely life-threatening, the patient may choose from various treatment options , even doing nothing if the problem is not causing you serious concern. Drugs can be prescribed o to try to prevent further attacks but it must be kept in mind that there is no real way of predicting ahead of time whether a given drug will be effective. Currently , most individuals with troublesome arrhythmia choose to have an electrophysiology study (EP Study) and catheter ablation procedure to destroy the short circuit and cure the PSVT. The success rate for catheter ablation is greater than 95% with the first procedure. Some people , fewer than 5 % , require a second procedure.
EP Study & Ablation
The electrophysiology (EP) study is done to determine what is causing your PSVT and whether it can reasonably ablated or “fixed”. It is a day procedure and is done by the team in the electrophysiology laboratory or EP lab at the University Hospital. This can be thought of as doing an ECG or electrocardiogram from “inside” the heart rather than the outside. Catheters or “wires” are placed in the heart by inserting needles in selected veins after freezing the area of the skin with local anesthetic . The catheters are used to record electrical activity in the heart or provoke the arrhythmia for us allowing it to be assessed. After the EP study is finished, a catheter ablation can be done during the same session to “burn” the short circuit area ( usually only a small area in the order of millimeters needs to be burned) to cure either the WPW or AVNRT problem. The whole procedure generally takes about 3 hours on average from entry to leaving the laboratory .
Although generally quite safe ,there are complications that need to be discussed with your physician. Most are not life-threatening risks and you need be aware of the most common risks. The overall chance of a complication is 1-3% and includes:
- Collapsed Lung
- Bleeding & bruising
- Damage to heart and/or blood vessels
- Blood clots in vein
- Mild pain in the groin and shoulder
- Stroke or heart attack
Q. How long will the ablation take?
A. On the average, 3 hours!
Q. When can I go home after my ablation?
A. Most people go home the same day.
Q. Who is doing the procedure?
A. We have a team of 6 permanent arrhythmia doctors and up to 4 cardiologists doing extra training in arrhythmia who work with us to assist . The schedule varies from day to day but there is close teamwork and multiple physicians may become involved as required by the complexity of the problem.
Q. Will I be put to sleep for the procedure?
A. General anesthesia is not usually needed for the procedure but an anesthetist or the nurses may give you intravenous medications to help you relax and sleep during the procedure. General anesthesia is available if necessary.