Presentation
Diagnosis At present, there are no diagnostic criteria for SQTS. [litfl.com]
Clinical presentation The clinical presentation of SQTS is also diverse with a high penetrance but a great variability of expression between different families and even among members of the same family. SQTS is characterized by a high lethality. [escardio.org]
All probands presented with a QTc below 320 ms without evident structural heart disease. [ncbi.nlm.nih.gov]
Short Q-T syndrome is a congenital defect, which means it is present at birth. The condition is inherited from at least one parent. [my.clevelandclinic.org]
Self-terminating idiopathic ventricular fibrillation presenting as syncope: a 40-year follow-up report. J Intern Med. 1990;227:211-3. Campbell TJ. Characteristics of cardiac action potentials in marsupials. J Comp Physiol. 1989;158:759-62. [medigraphic.com]
Entire Body System
- Asymptomatic
In asymptomatic patients with a short QTc interval, observation without treatment is recommended 3. [e-cardiogram.com]
However, it should be emphasised that the prognosis of patients with asymptomatic SQTS still remains undefined. [ncbi.nlm.nih.gov]
While this is obvious in symptomatic patients, doubts may arise when dealing with asymptomatic patients, especially if they have no family history. [escardio.org]
Differences in twelve-lead electrocardiogram between symptomatic and asymptomatic subjects with short QT interval. Heart Rhythm. 2009;6:26771. Schimpf R, Bauersfeld U, Gaita F, Wolpert C. [medigraphic.com]
Anttonen O, Junttila J, Maury P, Schimpf R, Wolpert C, Borggrefe M, Giustetto C, Gaita F, Sacher F, Haissaguerre M, Sbragia P, Brugada R, Huikuri HV (2009) Differences in twelve-lead electrocardiogram between symptomatic and asymptomatic subjects with [springermedizin.de]
Cardiovascular
- Heart Disease
All probands presented with a QTc below 320 ms without evident structural heart disease. [ncbi.nlm.nih.gov]
All patients had a QT < 320ms and a QTc < 340ms with no evidence of structural heart disease ( NB. [litfl.com]
Consequently, this syndrome has to be excluded in patients without structural heart disease presenting with sudden cardiac death. Other symptoms often documented are syncope and palpitations. [escardio.org]
Workup
QT, RR, ST Intervals
- Short QT Interval
Atrial fibrillation in the setting of familial short QT interval. Heart Rhythm 2004; 1: S165 (abstract). [escardio.org]
Syndrome Note the short QT interval, tall, peaked T waves and nearly absent ST segments. [ncbi.nlm.nih.gov]
Short QT interval There is currently no universally accepted lower limit of normal for the QT interval that can be used to diagnose SQTS. [litfl.com]
Short QT interval and short QT syndromes. J Cardiovasc Electrophysiol. 2005;16:397-8. Bjerregaard P, Gussak I. Short QT syndrome: mechanisms, diagnosis and treatment. Nat Clin Pract Cardiovasc Med. 2005;2:847. [medigraphic.com]
- Prolonged QT Interval
In SQTS 1 quinidine has shown to produce a marked prolongation of the QT interval and ventricular effective refractory periods, prolongation of the ST segment and T wave duration, restoration of heart rate dependence of the QT interval, repolarization [escardio.org]
Rhythm
- Torsades De Pointes
Akar FG, Yan GX, Antzelevitch C, Rosenbaum DS (2002) Unique topographical distribution of M cells underlies reentrant mechanism of torsade de pointes in the long-QT syndrome. Circulation 105:1247–1253 PubMed CrossRef 3. [springermedizin.de]
Treatment
In asymptomatic patients with a short QTc interval, observation without treatment is recommended 3. [e-cardiogram.com]
Treatment Options 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 SQTS. [litfl.com]
Short QT syndrome: pharmacological treatment. J Am Coll Cardiol. 2004;43:14949. Schimpf R, Antzelevitch C, Hsu LF, Schickel S, Pollevick GD, Cordeiro JM, et al. [medigraphic.com]
Even though ICD is the only effective treatment, it also has specific problems in these patients. [escardio.org]
Gaita F, Giustetto C, Bianchi F, Schimpf R, Haissaguerre M, Calo L et al (2004) Short QT syndrome: pharmacological treatment. J Am Coll Cardiol 43:1494–1499 PubMed CrossRef 12. [springermedizin.de]
Prognosis
However, it should be emphasised that the prognosis of patients with asymptomatic SQTS still remains undefined. [ncbi.nlm.nih.gov]
Etiology
Interestingly, four of these five genes have been implicated in the etiology of long QT syndrome but with mutations in the opposite sense, that’s to say, loss of function mutations instead of gain of function mutations of potassium channels. [escardio.org]
Prevention
[…] appropriate discharges Prevention of symptomatic episodes of atrial fibrillation However, drugs must be used with caution since the long-term efficacy of drug therapy in preventing serious arrhythmic events has been studied only in SQTS 1 patients and [escardio.org]
But, it is important for anyone who knows they have SQTS to see a doctor for regular care to prevent sudden cardiac death or cardiac arrest. What causes SQTS? Short Q-T syndrome is a congenital defect, which means it is present at birth. [my.clevelandclinic.org]
This information is important because it supports the need to consider implanting an ICD for secondary prevention of CA even in young SQTS patients. Anttonen O, Junttila J, Giustetto C, et al. T-Wave morphology in short QT syndrome. [e-cardiogram.com]
Reprogramming the decay delay, sensitivity or both generally prevents inappropriate discharges. [ncbi.nlm.nih.gov]
Quinidine is currently the agent of choice, having been shown in SQTS 1 patients to markedly prolong both the QT interval and ventricular refractory period, with normalisation of ST segments and T waves and prevention of VF induction. [litfl.com]