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Give details regarding Super Ventricular Tachycardia. How does it affect the heart?

May 2014
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I am doing a report for school (8th grade) and need to interview a cardiologist. My topic is Super Ventricular Tachycardia.
How does SVT affect the heart?
What is AVNRT, AVRT, AT, and WPW?
What is the sequence of an SVT?
Thank you! XXXX
Posted Wed, 30 Oct 2013 in Hypertension and Heart Disease
Answered by Dr. Vivek Chail 1 hour later
Brief Answer:
Please find detailed answer below.

Detailed Answer:
Thanks for writing in to us.

I have read through your query in detail and appreciate your interest in the topic.

Please find answers to your specific questions below.

1. How does SVT affect the heart?

Supraventricular tachycardia (SVT) means that from time to time your heart beats very fast for a reason other than exercise, high fever, or stress. Another term used is paroxysmal supraventricular tachycardia (PSVT).

During an episode of SVT, the heart's electrical system doesn't work right, causing the heart to beat very fast. The heart beats at least 100 beats per minute and may reach 300 beats per minute. After treatment or on its own, the heart usually returns to a normal rate of 60 to 100 beats a minute.

The SVT usually stops on its own in over 90% patients. If it does not resolve on its own or the SVT continues for longer, the electrical impulses can cause a reset of the cardiac rhythm and this can lead to the heart beating in an abnormal manner which can get life threatening.

Most episodes of SVT are caused by faulty electrical connections in the heart camera. What causes the electrical problem is not clear. SVT also can be caused by certain medicines. Examples include very high levels of the heart medicine digoxin or the lung medicine theophylline.

2. What is AVNRT, AVRT, AT, and WPW?

Types of SVT include:
Atrioventricular nodal reentrant tachycardia (AVNRT).
Atrioventricular reciprocating tachycardia (AVRT),
Wolff-Parkinson-White syndrome (WPW)
Atrial tachycardia (AT)

AVNRT occurs when a reentry circuit forms within or just next to the atrioventricular (AV) node.

Atrioventricular reciprocating tachycardia (AVRT) occurs when there is an extra electrical pathway linking the upper (atria) and lower (ventricles) chambers of the heart.

In Wolff-Parkinson-White Syndrome (WPW), a 'bypass tract' avoids this node and its protection and the fast rate may be directly transmitted to the ventricles. This situation has characteristic findings on ECG.

Atrial tachycardia is a type of atrial arrhythmia in which the heart's electrical impulse comes from an ectopic atrial pacemaker rather than from the SA node. This is an automatic type of SVT.

3. What is the sequence of an SVT?

To know the sequence of SVT I suggest you please follow the link below which will help you to understand the sequence of events through pictures.


Hope your query is answered.
Do write back in case of doubts.

Dr. Vivek
Above answer was peer-reviewed by
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