Pathophysiology (The HOW?)

Pathophysiology (The HOW?)

This week we will discuss how Pediatric Long QT Syndrome (abbreviated LQTS) occurs. I briefly discussed this already in my first introductory blog post.  LQTS is a genetically inherited condition. This means that there weren’t any lifestyle changes or modifiable behaviors that could have been done to prevent this problem. Patients are born with this abnormality already written into their genetic code (Raghavan 2014). It also means that if an adult diagnosed with LQTS is interested in having children they should consult a physician to make a game plan that discusses screening future offspring for this syndrome.

As we talked about in the first blog post, your heart is a muscle. This muscle pumps blood throughout your system by squeezing and contracting. Electrical signals tell your heart when to squeeze and when to contract. These electrical signals are made as ions such as potassium and sodium flow in precise amounts in and out of cells (SADS 2008). In LQTS the channels that these ions move through are not regulated correctly. This causes the dangerous irregularity in the heart’s rhythm that we see with LQTS.

As a picture is worth a thousand words I thought that some videos would be even better.

Here’s a great short video that describes the cause of LQTS in case you are more of a visual person:  https://www.youtube.com/watch?v=3n3So15GY34

Here’s a slightly longer video of Dr. Sanjay Sharma giving a very well spoken description of general LQTS:  https://www.youtube.com/watch?v=Fk-YVgYFUtY

My personal favorite video is this patient and family’s perspective of their experience with diagnosis of Pediatric Long QT Syndrome:  https://www.youtube.com/watch?v=_9eMJv669dM

Remember when we talked the first week about EKG’s? I explained how EKG’s give us a visual picture of the electrical signals powering the different parts of the heart to squeeze and release (SADS 2008). Well here’s a great picture that shows the difference between a normal EKG and that of a patient with LQTS:

EKG difference between normal heart and LQTS heart

 See the smoothly rounded hump in the picture above? The important part of the picture is that the normal (top) EKG strip has a small rounded bump for the QT interval whereas the LQTS (bottom) EKG strip has an elongated hump for the QT interval. It is this electrical change that can cause problems with the pace and rhythm of the heart in LQTS.

I hoped that this blog post helped us review some earlier information and learn new information on how Pediatric Long QT Syndrome occurs. Next week we will talk about how a formal diagnosis of LQTS is made in our pediatric population.

~Until the next beat~

Sarah

Sources:

Long QT Syndrome. (2008, June 1). Retrieved January 25, 2015, from http://www.sads.org/library/long-qt-syndrome#.VMSbrXDF87g

Raghavan, S. (2014, June 26). Pediatric Long QT Syndrome . Retrieved January 25, 2015, from http://emedicine.medscape.com/article/891571-overview