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]

• Hyperthermia

  Secondary causes of short QT must also be excluded and include hyperthermia, hyperkalemia, hypercalcemia, acidosis and alterations of the autonomic tone. [escardio.org]

  […] of structural heart disease. 1, 2 SQTS was first described as a new clinical entity by Gussak et al. in 2000. 1 Until then shortening of the QT interval had only been reported in the context of electrolyte imbalances (hyperkalaemia, hypercalcaemia), hyperthermia [ncbi.nlm.nih.gov]

• Palpitations

  The diagnosis is based upon the patient’s symptoms (e.g. syncope, palpitations), family history (of syncope, sudden death or atrial fibrillation at an early age) and characteristic findings on the 12-lead ECG. [litfl.com]

  The most common symptoms are: Heart pounding (palpitations) Fainting (syncope) Sudden cardiac death (may be the first symptom for some patients) Atrial fibrillation If SQTS causes atrial fibrillation, other symptoms may include shortness of breath, dizziness [my.clevelandclinic.org]

  Other symptoms often documented are syncope and palpitations. [escardio.org]

  Cardiac arrest seems to be the most frequent presenting symptom (up to 40 %). 5 Palpitations are very common (30 %), followed by syncope (25 %) and AF, which is the first presenting symptom in up to 20 % of patients. [ncbi.nlm.nih.gov]

• Suggestibility

  Population-based and genetic studies show that QTc interval 6 – 8 Data from over 10,000 adults suggest that, in the healthy population, the prevalence of QT c 6 Therefore, males with QTc 330 ms and females with QT c 340 ms have abnormally short QT and [ncbi.nlm.nih.gov]

  Known patients with SQTS genotypes 1-3 all had QTc intervals 300-320 ms Known patients with SQTS genotypes 4 & 5 all had QTc intervals 360 ms A recent review by Viskin suggested the following approach: QTc intervals 330 ms in males or 340 ms in females [litfl.com]

  Isolated reported cases (16) suggest that it may facilitate appropriate decision-making in symptomatic patients with an abnormal but nondiagnostic ECG given the prognostic and therapeutic implications. [escardio.org]

• Impulsivity

  The Q-T interval is the section on the electrocardiogram (ECG) that represents the time it takes for the electrical system to fire an impulse through the ventricles (lower chambers of the heart) and then recharge. [my.clevelandclinic.org]

• Short QT Interval

  Atrial fibrillation in the setting of familial short QT interval. Heart Rhythm 2004; 1: S165 (abstract). [escardio.org]

  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]

• Peaking T Wave

  […] particularly in the precordial leads Short or absent ST segments Episodes of atrial or ventricular fibrillation QT, ST and T-wave changes in SQTS Short QT interval, peaked T waves and short ST segments in two patients with SQTS 1. [litfl.com]

  T waves and nearly absent ST segments. [ncbi.nlm.nih.gov]

  SQTS 16 often have tall, peaked and symmetrical T waves, SQTS 38 show asymmetrical peaked T wave due to the acceleration of the final phase of the action potential repolarization, and SQTS 4 and 59 coexist with Brugada type ST elevation in precordial [escardio.org]

• Prominent U Wave

  U wave can be observed, separated by an isoelectric T–U segment. 14 Longer T peak – T end interval may be observed, suggestive of augmented transmural dispersion of refractoriness. 15 Depression of the PQ segment, due to a heterogeneous abbreviation [ncbi.nlm.nih.gov]

• Prominent A-Wave

  U wave can be observed, separated by an isoelectric T–U segment. 14 Longer T peak – T end interval may be observed, suggestive of augmented transmural dispersion of refractoriness. 15 Depression of the PQ segment, due to a heterogeneous abbreviation [ncbi.nlm.nih.gov]

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]

Even though ICD is the only effective treatment, it also has specific problems in these patients. [escardio.org]

In asymptomatic patients with a short QTc interval, observation without treatment is recommended 3. [e-cardiogram.com]

Short QT syndrome: pharmacological treatment. J Am Coll Cardiol. 2004; 43 :1494–9. [ PubMed ] [ Google Scholar ] 33. Wolpert C, Schimpf R, Giustetto C et al. [ncbi.nlm.nih.gov]

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]

However, it should be emphasised that the prognosis of patients with asymptomatic SQTS still remains undefined. [ncbi.nlm.nih.gov]

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]

[…] 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]

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]

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]