If you know us, you may have heard Melissa and I talk about our son’s “extremely rare heart condition”. Translation: Hudson has Short QT Syndrome.
Here is a quick description, for any of you have been wondering about what that really means. Short QT Syndrome (or Short QT) is a condition that can cause a disruption of the heart’s normal rhythm (arrhythmia).
Short QT refers to a specific pattern of heart activity that is detected with an electrocardiogram (EKG), which is a test used to measure the electrical activity of the heart.
If you were looking at a schematic representation of a normal EKG, the part of the heartbeat known as the QT interval is abnormally short in people who have Short QT.
In people with Short QT, the heart (cardiac) muscle beats at a normal rate, but the time it takes to recharge or recover between beats (the QT interval) is much shorter.
Another symptom of Short QT is that the QT interval does not change as the speed of the heartbeat changes. Under normal circumstances, the QT interval gets longer when the heart beats slower and shorter when the heart beats faster. Not so in people with Short QT.
The main electrocardiographic abnormalities seen in Short QT are:
- Short QT interval
- Lack of the normal changes in QT interval with heart rate
- Peaked T waves, particularly in the precordial leads
- Short or absent ST segments
- Episodes of atrial or ventricular fibrillation
Mutations in the KCNH2, KCNJ2, and KCNQ1 genes cause Short QT. Hudson’s version is KCNJ2, and his phenotype looks like this:
If untreated, the arrhythmia associated with Short QT can lead to a variety of signs and symptoms, including a rapid, strong, or irregular heartbeat, dizziness and fainting, and cardiac arrest or sudden death. These signs and symptoms can occur any time from early infancy to old age. This condition may explain some cases of sudden infant death syndrome (SIDS), which is a major cause of unexplained death in babies younger than 1 year.
However, some people with Short QT never experience any health problems associated with the condition. May it be so for Hudson!
Efforts to find a suitable pharmacological treatment have focused on potassium blocking anti-arrhythmic agents. Quinidine is currently the agent of choice, and is currently what Hudson is taking to put off the implantation of an Implantable Cardioverter Defibrillator (ICD).
At present, the only effective treatment is implantation of an ICD. The main problem with this is T-wave oversensing and inappropriate shocks due to the tall, narrow T waves seen in Short QT.
Short QT syndrome is still a relatively new disease: It was first described in 2000, and elucidation of the genetic, electrophysiological and clinical abnormalities associated with the disease has only taken place over the past few years.
Short QT appears to be rare. At least 70 cases have been identified worldwide since the condition was discovered in 2000. However, the condition may be underdiagnosed because some affected individuals never experience symptoms. (Personal note: of these known cases, we are only aware of 3 that have autism, Hudson being one of them.)
So there you have it! A quick “Short QT for Dummies” for those of us who have never heard of it. Trust me, we hadn’t. When Hudson was diagnosed with Short QT this was all news to us.
What’s next? We don’t know. Hudson is being treated with Quinidine with some success, but he also has several other diagnoses. We are constantly trying to treat all of his stuff at once, which can be difficult.
Mainly, in regards to his heart condition, we are praying that Hudson will not have to have an ICD implant anytime soon. The ideal would be to wait until he is at least 11, to give his body time to mature and stabilize.
We invite you to join with us in prayer for that.
I have borrowed extensively from and in many cases quoted directly or paraphrased information from the following sites:
Images (not necessarily related to SQTS):