Diagnosis

This week we will discuss how Long QT Syndrome (abbreviated LQTS) in our pediatric population is diagnosed. As I have mentioned in the previous blog posts, this condition is often unknown until a child experiences very serious cardiac symptoms such as loss of consciousness and cardiac arrest (Gajewski & Saul 2010).  In an optimal situation a first responder would begin CPR and utilize a nearby defibrillator to revive the child to limit potential long-term consequences of this event. Once the child is transported to the hospital the workup for the cause and further treatment of the cardiac arrest begins. Laboratory tests may be completed in order to rule out any electrolyte abnormalities or other causes of symptoms. While no blood draw is fun for anyone, here’s a great example of how setting up a positive environment and teamwork with providers and caregivers can make a non-traumatic experience for the child:  https://www.youtube.com/watch?v=5UNP0Gjx2F4

Most importantly to diagnose Long QT Syndrome, an EKG or ECG (same test, different name) is completed to study the conduction of the heart. In this test sticky monitors are placed on the child’s body to create a picture of how the heart is functioning. These electrodes do not cause any pain/discomfort.

Here’s a kid-friendly video that shows what an EKG/ECG is like: https://www.youtube.com/watch?v=MSc0Trc_d88

Most importantly a pediatric cardiologist will be involved in the immediate and long-term management of this child’s cardiac condition. Many hospitals are offering prophylactic screening with EKG’s during annual sports physicals of young athletes to try to identify a problem such as LQTS before it becomes a life-threatening issue in that child. Here’s a video from Miami Children’s Hospital describing how helpful these screenings can be to a child’s overall health:  https://www.youtube.com/watch?v=dVX37frwDMA

Source:

Gajewski, K., & Saul, J. (2010). Sudden cardiac death in children and adolescents (excluding Sudden Infant Death Syndrome). Annual Pediatric Cardiology, 3(2), 107-112. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3017912/

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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

Epidemiology (The WHO)

Last week I gave an introduction to the blog and the importance of learning about Long QT Syndrome (abbreviated here as LQTS). This week’s blog will focus on the epidemiology of LQTS. When we ask ourselves the who, what, where, when, and why of a disease process, epidemiology refers to the WHO. Who gets this disease? Is it children from a specific ethnic background or geographic location? Is it more prevalent in males or in females? Is it genetically passed from parent to child? This blog post will have a lot more number crunching in it…but don’t get too flustered because while a lot of science involves understanding the statistics behind a disease, I generally am more focused on why the numbers matter.

LQTS is under diagnosed because children often only find out that they have the condition once they have had a related cardiac incident or if an EKG was completed during a child’s development. Additionally, parents that are carriers for the genetic mutations that cause this syndrome often do not have any of the worrisome symptoms of LQTS, thus they may have unknowingly transmitted it genetically to their offspring. Because of these issues it is hard to get good data on the big picture of who is getting this disease…but here’s some numbers so that you can understand a general idea of the situation.

Currently LQTS may be expected to occur in 1/10,000 people (Solvari, et al 2014). However another study found the prevalence of LQTS to be up to 1/2000 in Caucasian infants (Schwartz, et al 2009).

There is a higher prevalence (60-70%) of females diagnosed with LQTS to males. As women already have been found to have a longer QT interval then men, this could be one of the key features that predispose women to having the genetic variants that causes LQTS (Locati, et al 1998). Furthermore, Finnish and Norwegian populations have been found to carry more of the genetic mutations that lead to this syndrome (Berge, et al 2008). Lastly, these genetic mutations can be passed on to future children—so it is important for adults with LQTS who are interested in bearing children to work with a physician to help prevent complications.

As demonstrated by the number crunching above, there is a lot of variability in the predicted prevalence of LQTS. Some researchers are concerned about an increase in frequency of diagnosis of LQTS. New studies are looking to understand if the frequency of diagnosis is increasing because more children have the disease, or is it that we are just doing a better job of looking for it before it causes an unexpected problem. You know all those “well child physical exams” that are required prior to participating in a youth sport or activity? Well those screening appointments are often specifically looking for LQTS in our pediatric population.

See you next week for a talk about the pathophysiology (the how it works) of pediatric Long QT Syndrome!

~Until the next beat~
Sarah

Sources:

Berge, K., Haugaa, K, et al. (2008). Molecular genetic analysis of long QT syndrome in Norway indicating a high prevalence of heterozygous mutation carriers. Scand J Clin Lab Invest., 68(5), 362-8. Retrieved from Pubmed, http://www.ncbi.nlm.nih.gov/pubmed?Db=pubmed&Cmd=ShowDetailView&TermToSearch=18752142

Locati, E., Zareba, W, et al. (1998, June 9). Age- and sex-related differences in clinical manifestations in patients with congenital long-QT syndrome: Findings from the International LQTS Registry. Retrieved January 18, 2015, from http://www.ncbi.nlm.nih.gov/pubmed/9631873

Schwartz, P., Stramba-Badiale, M, et al. (2009). Prevalence of the congenital long-QT syndrome. Circulation AHA, 120(18), 1761-7. Retrieved from Pubmed, http://www.ncbi.nlm.nih.gov/pubmed/19841298

Solvari, A. (2014, April 22). Long QT Syndrome  (J. Rottman, Ed.). Retrieved January 18, 2015, from http://emedicine.medscape.com/article/157826-overview#a0156

Week 1 -- Welcome!

I am a nursing student at the University of Washington--Seattle. I am currently enrolled in a class that uses student blogging to help us practice teaching our patients about a disease. In case you haven't figured it out yet from the title of this blog...I have chosen to write about Pediatric Long QT Syndrome.

Your heart is a muscle. This muscle is told to beat (contract and relax) because an electrical signal travels throughout the heart. We use a test called an EKG (picture #1 below) to look at how strong and fast this electrical signal is stimulating various parts of the heart. Each part of the EKG refers to a different part of the heart’s cycle. In long QT syndrome we see on an EKG that the time between the Q wave and the T wave is too long. See picture #2 below for comparison of long QT waveforms to a normal EKG.

Here's a kid friendly video that shows how an EKG works: EKG Video for Kids

Picture #1 EKG        

(http://www.nhlbi.nih.gov/health/health-topics/topics/qt)

Picture #2 Comparison of Normal EKG to Long-QT Syndrome EKG

(http://washingtonhra.com/13.html)

Why is this important? This syndrome is found in young athletes and can cause serious cardiac issues during physical exertion--such as at football practice, or during an endurance running event. When the timing of electrical impulses in the heart is misfiring, such as seen with this syndrome, a critical situation such as sudden cardiac death can occur (Gajewski & Saul 2010).

Throughout my weekly blog updates I will discuss how screening of youth athletes can help identify this problem, as well as signs and symptoms, causes, and treatments for this condition.

~Until the next beat~

Sarah



Source: Gajewski, K., & Saul, J. (2010). Sudden cardiac death in children and adolescents (excluding Sudden Infant Death Syndrome). Annual Pediatric Cardiology, 3(2), 107-112. Retrieved from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3017912/