Talk:Long QT syndrome

Drugs causing prolonged QT interval

This list starting the LQTS page would in my opinion be better suited in a separate article, especially since the list should be much longer when updated. In stead there should be an appropiate link to the list in the aquired LQTS section

Genetic Testing

Genetic testing was discussed in JAMA on 21 Dec 05[1]. JFW | T@lk 21:55, 22 December 2005 (UTC)

Side effect of anti-psychotics

Side effect of anti-psychotics based on PI sheets for Haldol and Geodon. John Elder 02:17, 28 March 2006 (UTC)

LQT2 Section, Grammar

in the article http://en.wikipedia.org/wiki/Long_QT_syndrome, 
              should the txt under LQT2, "are poised so drug binding to them 
              will", be "drugs" or some gramatical change?

I changed this to "a drug". 6/18/08

Left Cardiac Sympathetic Denervation

Left Cardiac Sympathetic Denervation is absent from the article.   — C M B J   22:44, 17 December 2008 (UTC)

Non-genetic causes

I have removed a long list (unsourced) with conditions and states in which the QTc interval may be prolonged. They don't belong in this article, because they are not "syndromal". They need to be discussed in another article, either about QTc prolongation or TDP.

More common than the various congenital causes of long QT syndrome are acquired causes. They can be divided into two main categories - those due to disturbances in blood electrolytes and those due to various drugs:

• electrolyte disorders
  • hypokalemia
  • hypomagnesemia
  • hypocalcemia
• drug-induced
  • Antiarrhythmic drugs
    • Quinidine
    • Amiodarone
    • Sotalol
    • Procainamide
    • Ranolazine
  • Antihistamines
    • terfenadine
    • astemizole
  • Antibiotics
    • Macrolide
      • Erythromycin
    • Certain Fluoroquinolone antibiotics
      • Moxifloxacin
  • Major tranquilizers (i.e. antipsychotics)
    • Chlorpromazine
    • Haloperidol
  • Tricyclic antidepressants
  • Gastrointestinal Motility agents
    • Cisapride
    • Domperidone
  • Antipsychotic drugs
    • Haloperidol
    • Quetiapine
    • Thioridazine
    • Droperidol
  • Analgesics
    • Methadone
    • LAAM

Just as with the congenital causes of the Long QT syndrome, the acquired causes may also lead to the potentially lethal arrythmia known as Torsade de Pointes. Treatment is straightforward - replace any deficient electrolytes if present and stop any culprit drugs if the patient is using one (or more).

Given its relatively high frequency of use, its tendency for drug-drug interaction, and its inherent ability to prolong the QT interval, the macrolide antibiotic erythromycin is probably the most prevalent cause of acquired long QT syndrome. Indeed, use of erythromycin is associated with a rate of death more than double that of use of other antibiotics

In addition to the two major categories listed above, it should be noted that there are also some miscellaneous causes of QT prolongation such as anorexia nervosa, hypothyroidism, HIV infection, and myocardial infarction.

Hope this is OK.

References

-- JFW | T@lk 14:59, 14 February 2010 (UTC)

QT interval sounds like the right place. JFW | T@lk 15:15, 14 February 2010 (UTC)

NEJM 2008

NEJM covered this in 2008 doi:10.1056/NEJMcp0706513 JFW | T@lk 12:53, 6 March 2011 (UTC)

Comparison Picture

could there be added a comparison picture of what a LQT looks like —Preceding unsigned comment added by 71.112.216.33 (talk) 17:08, 23 March 2011 (UTC)

treatment

What about using primidone as a treatment. It is mentioned in the primidone article that it has been used for this purpose.

AriaNo11 (talk) 18:11, 28 April 2011 (UTC)

Have a source for that? JFW | T@lk 20:18, 28 April 2011 (UTC)

Potassium supplementation as a treatment - *no* evidence?

It states that the use of potassium as a potential treatment is not evidence-based - I can understand this, but doesn't reference even an anecdotal reports of long QT going into remission after potassium supplementation, and/or in vitro studies of the effect of K supplementation on the functions of the various ion channels. I find it hard to believe there isn't *any* evidence whatsoever. — Preceding unsigned comment added by 98.223.232.121 (talk) 18:16, 30 January 2012 (UTC)

Inappropriate citation

Hi Editors,

Checked on citation #13, Challenges of Diagnosis of Long-QT Syndrome in Children, this article does not support the claim made, nor is the claim cited within the article, appears to be a mistaken citation. — Preceding unsigned comment added by 152.132.10.133 (talk) 18:41, 4 September 2015 (UTC)

Too technical?

The language here is fairly technical and given without context, and I believe it should be marked.learnergenius (talk) 03:58, 2 February 2017 (UTC)

Broken reference

The link in reference #2 is broken. Here's a link that works, but I don't know how to update it in the article. http://www.mdedge.com/ccjm/article/94949/cardiology/congenital-long-qt-syndrome-considerations-primary-care-physicians — Preceding unsigned comment added by Trogyssy (talk • contribs) 16:21, 15 February 2017 (UTC)

fixed Jytdog (talk) 21:08, 15 February 2017 (UTC)

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The "50% death rate" stat

A stat that says that 50% of untreated LQTS patients die within 10 years keeps getting republished. The citation keeps referring to an LQTS overview page from from the NIH. This page IS NOT original research. This stat has been floating around the Internet and is reposted often by hospitals, schools, and even the NIH. It is patently false without the word "symptomatic" or "of patients who have had an LQTS triggered cardiac episode".

This is as absurd as a claim that McDonalds hamburgers kill 50% of people within 10 years, because some study of morbidly obese people who died within 10 years found half ate McDonalds.

The original research is clear that this stat is for SYMPTOMATIC patients. Stop reposting this claim without context, even if the citation seems semi-reputable. Once a person has a cardiac episode and LQTS is discovered, if THOSE people are leaving untreated, they have the 50% odds of dying within 10 years. This is far different from the asymptomatic person who discovers it via genetic testing. There is absolutely no hard evidence or even plausible anecdotal evidence that this is the case.

Recent source correctly using context

BillySalon (talk) 19:16, 4 February 2018 (UTC)BillySalon

Thanks for coming to talk finally. Please stop removing the NIH source and content based on it. If you believe the NIH has published incorrect information, please contact them and have it changed there. Thanks. Jytdog (talk) 21:48, 4 February 2018 (UTC)

Thanks for bringing that ref. I fixed the issue that I think is concerning you in this diff. Please make sure that the body of an article is corrected before, or when, the lead is corrected. Jytdog (talk) 22:00, 4 February 2018 (UTC)

The NIH is not a charity and but rather is the position of the largest health care institute in the world.

The review states "Among patients who have experienced a LQTS-triggered cardiac event (arrhythmic syncope, arrhythmic syncope followed by seizures, or aborted cardiac arrest), the untreated natural history is grim, with >50% mortality at 15 years"

The NIH says "More than half of the people who have untreated, inherited types of LQTS die within 10 years."

Fairly inline with each other. Doc James (talk · contribs · email) 23:23, 4 February 2018 (UTC)

Stress

There is a review on the topic and we summarize it already as "Mental stress or physical exertion may trigger arrhythmia in some people with LQTS."

No need for all the primary sources. Just to repeat what the review has said. Doc James (talk · contribs · email) 10:54, 24 December 2018 (UTC)

References

Risk Factors Suggestion

Hi @Doc James: I know you take a keen interest in this and many other medical articles so thought I'd flag up some proposed changes to see what you and others thought. I don't think the "Risk factors" section really belongs as it stands, there aren't risk factors for developing long QT syndrome per se, there are genetic and acquired causes which are dealt with in the preceding section. There are triggers for arrhythmias, but these are dealt with in part in the symptoms section, and this can be expanded in the pathophysiology section. I am therefore inclined to remove "Risk factors" but thought I'd bring it to the table first to see if anyone has a strong reason for it to stay. PeaBrainC (talk) 06:21, 25 January 2019 (UTC)

Looking further, some comprehensive reviews such as Roden 2004 in NEJM have a list of risk factors for developing Torsades, perhaps it could be rephrased in this context? PeaBrainC (talk) 06:56, 25 January 2019 (UTC)

Sure sounds good User:PeaBrainC. I was thinking the same. Doc James (talk · contribs · email) 17:00, 25 January 2019 (UTC)

Hi @Doc James:. I'm not sure where the risk factors for TdP should sit. I see you moved them to a subsection of Signs and Symptoms but it doesn't quite work there - an important aspect of the risk relates to the interaction between genetic and acquired causes, but these concepts need to be explained first. It seems logical that a section or risk should be after the causes. How about renaming the section Risk stratification and putting it around the treatment section. This might then sit logically with a discussion of how those at highest risk should receive ICDs. What do you think? PeaBrainC (talk) 10:42, 29 January 2019 (UTC)

These are risks for developing symptoms rather than developing the condition correct? User:PeaBrainC As such I felt they fit under symptoms.

Doc James (talk · contribs · email) 00:55, 30 January 2019 (UTC)

@Doc James: - You're absolutely right that they're risk factors for developing symptoms. However, reading the article, the risks section mentions concepts (inherited vs acquired LQT, drug-induced LQTS) that are only presented later, in the causes section. As it stands the article doesn't flow and the non-expert reader has to read ahead to make sense of what has been said before. These concepts need to be explained first, so in my view the risks section should appear later. As suggested above, how about a 'Risk Stratification' subheading in the treatment section?

Organisation of causes section

The causes section as it stands is a bit of a mess. Causes is currently divided into Acquired and Genetics, with genetics being split into 16 subheadings of LQT1 through LQT16, all of which is pretty intimidating and difficult to read. Some of this could be condensed with "Main Article:" links to the relevant subtypes.

How about this for a proposed re-organisation:

• Acquired
• Congenital
• Initial description of main genetic forms with the current genetics table followed by subheadings of

• Romano ward syndrome (Focus on LQT1-3 with mention of other forms, detail could be shunted to Romano-Ward article)
• Jervell-Lange-Nielsen syndrome
• Andersen-Tawil syndrome
• Timothy syndrome

If there are no dissenting views I'll aim to do this (at some point). PeaBrainC (talk) 16:02, 16 June 2019 (UTC)

Sounds great. I do wonder how to best communicate the interaction between congenital and acquired causes. JFW | T@lk 16:27, 16 June 2019 (UTC)

My ip edit to the lead, just ended

   (Sorry for the ip edit; seems like mebbe the iPad 2 wp icon forgets after a few days that an admin logged me in, and only Google lets me log myself in. Or maybe my net provider changed too high-order a bit in my IP address. Further Wonders of the InterWebs!)
   Anywhoo, the signs and symptoms and outcomes portion of the lead was dreadful, at least as a lead. Instead, I reworded to sort out the underlying mechanisms from the most relevant consequences, and avoided the false hint that drowning (though often fatal) is not a form of death, but rather an often remediable hazard. (I'll go back and be sure that I linked to drowning.)
--JerzyA (talk) 02:38, 17 June 2019 (UTC)

   Sorry, drowning is sometimes fatal and sometimes not; uses of double negatives are more often amusing than fatal.
--JerzyA (talk) 02:45, 17 June 2019 (UTC)

We should try to write in easier to understand language. One way to do this is to use shorter sentences. I have thus restored it to shorter sentences.

This is hard to parse "carrying increased risk of an irregular heartbeat with effects that may be seen in palpitations or fainting, and may result in drowning or sudden death" Doc James (talk · contribs · email) 02:52, 17 June 2019 (UTC)

Not for me. kencf0618 (talk)

Seizure

Long QT syndrome does not cause "Epileptic seizure"

Tester DJ, Schwartz PJ, Ackerman MJ (2013). "Congenital Long QT Syndrome". In Gussak I, Antzelevitch C (eds.). Electrical Diseases of the Heart. London: Springer. pp. = 39–46. doi:10.1007/978-1-4471-4881-4_27. ISBN 978-1-4471-4881-4.{{cite book}}: CS1 maint: extra punctuation (link)

Despite the source saying "With an incidence as high as 1 in 2,000–2,500 live births, long QT syndrome (LQTS) is often characterized clinically by prolongation of the heart rate corrected QT interval (QTc) on a 12-lead surface electrocardiogram (ECG) and is associated with syncope, seizures, and sudden cardiac death due to ventricular arrhythmias usually following a precipitating event such as exertion, extreme emotion, or auditory stimulation."

Doc James (talk · contribs · email) 22:23, 18 December 2019 (UTC)

Ref can be seen here[2]

They may be referring to "seizure like activity" Doc James (talk · contribs · email) 22:29, 18 December 2019 (UTC)

Sorry Doc, but I think you’re mistaken. Anoxic seizures can be associated with arrhythmias or even vasovagal syncope and can be indistinguishable from seizures caused by epilepsy. LQTS is not uncommonly (and tragically) misdiagnosed as epilepsy, to the extent that it is common practice in the assessment of these patients to ask about a family history of epilepsy. The source is correct. PeaBrainC (talk) 23:02, 18 December 2019 (UTC)

Whenever I request an electroencephalogram the neurophysiologist performs an ECG and includes the QTc in the report. JFW | T@lk 22:07, 19 December 2019 (UTC)

User:Doc James - many sources describe seizures as being a feature of LQTS e.g. 1, 2,3. This isn't to say that they have epilepsy, but the convulsions these patients experience are referred to by many reliable secondary sources as "seizures". For a specific review of this very subject see Davis and Wilkinson 1998, PMID:9767499. To quote: "Patients with LQTS may be mistakenly thought to have a seizure disorder as cerebral hypoxia may cause seizure activity."

For the purposes of the wiki, "seizures" is a term both understood by many informed laypersons, and appears to be accurate as shown by it's use in academic papers on this subject. Unless others have strong opinions to the contrary, I am inclined to change the wording back to how it was before. PeaBrainC (talk) 12:10, 20 December 2019 (UTC)

It is not however an epileptic seizure. People get seizure like activity with syncope fairly frequently, but in my opinion it is better to refer to it as seizure like activity to reduce confusion.

Of course long QT is in the differential diagnosis of an epileptic seizure. Doc James (talk · contribs · email) 12:19, 20 December 2019 (UTC)

This ref says "may cause syncope or seizure like activity in a previously well child"[3] Doc James (talk · contribs · email) 12:32, 20 December 2019 (UTC)

This source says "Nonepileptic events look like seizures, but actually are not. Conditions that may cause nonepileptic events include ... abnormal heart rhythms (arrhythmias)."[4]

This one says "the term nonepileptic episodic events is often considered synonymous with physiologic nonepileptic seizures in the literature"[5] Doc James (talk · contribs · email) 12:51, 20 December 2019 (UTC)

Ok, sounds like we both agree that those with Long QT can experience convulsions. Our differences relate to how to describe these symptoms.

Doing some further digging (and learning something new in the process) the spanner in the works is that those with LQT are also more likely to have epilepsy due to shared expression of the mutant ion channels in heart and brain, and that this could be an explanation for the cases of sudden death in epilepsy.

See Madan 2017 for review: "Johnson et al77 described a novel LQT2-epilepsy association. They demonstrated that a seizure phenotype was far more common in patients with LQT2 compared to either background rates or to patients with LQT1. A positive seizure phenotype was also more common in LQT2 compared to LQT3; however, total number of LQT3 patients was low and consequently not statistically significant. Noncardiac-organ phenotypes observed in other LQTS-susceptibility genes such as KCNQ1/deafness and SCN5A/gastrointestinal symptoms and LQT2-causing perturbations in the KCNH2-encoded potassium channel may confer susceptibility for recurrent seizure activity.77 Tiron et al78 discovered a KCNQ1 mutation in a family suffering from both phenotypes, suggesting that KCNQ1 genetic variations may confer susceptibility for recurrent seizure activity increasing the risk of sudden death.".

LQTS is therefore associated with both epileptic and non-epileptic seizures. Perhaps this could be spelt out in the text? PeaBrainC (talk) 13:30, 20 December 2019 (UTC)

So some types of LQT is also associated with epilepsy / epileptic seizures. Seperate from the cardiac arrhythmia resulting in nonepileptic events though. Sure could be added. Doc James (talk · contribs · email) 13:33, 20 December 2019 (UTC)

Done. PeaBrainC (talk) 13:40, 20 December 2019 (UTC)

User:PeaBrainC have split the sentence into one on convulsive syncope and one on the increased risk of epilepsy in LQT2. Clarified that seizure like activity is also known as non epileptic seizures. Doc James (talk · contribs · email) 00:24, 21 December 2019 (UTC)