scholarly journals Prolonged QT interval on electrocardiogram and fainting — is there always a relationship?

2021 ◽  
Vol 102 (5) ◽  
pp. 747-750
Author(s):  
Yu S Mishanina ◽  
V N Oslopov ◽  
Yu V Oslopova ◽  
Yu E Teregulov ◽  
E V Khazova
Keyword(s):  
Sudden Cardiac Death ◽  
Long Qt Syndrome ◽  
Qt Interval ◽  
Cardiac Death ◽  
Vasovagal Syncope ◽  
Tilt Test ◽  
Long Qt ◽  
Prolonged Qt Interval ◽  
Prolonged Qt ◽  
Qt Syndrome

Using a clinical example, the article draws the attention of doctors to the problem of the prolonged QT interval (long QT) and the related problem of fainting (syncope). Syncope is a component of long QT syndrome, and syncope is a precursor of sudden cardiac death. However, syncope in a patient with long QT syndrome may have pathogenesis that is completely unrelated to abnormalities of cardiac ion channels. In other words, such a patient may have a second disease as a syntropy relates to prolonged QT interval, to an extent mimicking long QT syndrome. The presented medical history of a 33-year-old patient S. shows the complexity of differential diagnosis of the causes of syncope. The crucial part in the diagnosis, in addition to the clinical picture, was the so-called tilt test, little-known to general medical practice, as well as the laboriousness of making a final diagnosis of the long QT Syndrome type 2, which required a molecular genetic study whole-exome sequencing. Patient S. had vasovagal syncope that not associated with long QT syndrome, but she has a risk of sudden cardiac death, and the article identifies therapeutic and other measures to reduce this risk.

scholarly journals Prolonged QTc: "Mind the Gap"

2014 ◽  
Vol 2 (1) ◽  
pp. 44-45
Author(s):  
Ahmad Mursel Anam ◽  
Raihan Rabbani ◽  
Farzana Shumy ◽  
M Mufizul Islam Polash ◽  
M Motiul Islam ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Long Qt Syndrome ◽  
Qt Interval ◽  
Torsades De Pointes ◽  
Junior Doctors ◽  
Long Qt ◽  
Acquired Long Qt Syndrome ◽  
Prolonged Qt Interval ◽  
Prolonged Qt ◽  
Qt Syndrome

We report a case of drug induced torsades de pointes, following acquired long QT syndrome. The patient got admitted for shock with acute abdomen. The initial prolonged QT-interval was missed, and a torsadogenic drug was introduced post-operatively. Patient developed torsades de pointes followed by cardiac arrest. She was managed well and discharged without complications. The clinical manifestations of long QT syndromes, syncope or cardiac arrest, result from torsades de pointes. As syncope or cardiac arrest have more common differential diagnoses, even the symptomatic long QT syndrome are commonly missed or misdiagnosed. In acquired long QT syndrome with no prior suggestive feature, it is not impossible to miss the prolonged QT-interval on the ECG tracing. We share our experience so that the clinicians, especially the junior doctors, will be more alert on checking the QT-interval even in asymptomatic patients. DOI: http://dx.doi.org/10.3329/bccj.v2i1.19970 Bangladesh Crit Care J March 2014; 2 (1): 44-45

Evaluation of Prolonged QT Interval: Structural Heart Disease Mimicking Long QT Syndrome

2017 ◽  
Vol 40 (4) ◽  
pp. 417-424 ◽  
Author(s):  
ADAYA WEISSLER-SNIR ◽  
MICHAEL H. GOLLOB ◽  
VIJAY CHAUHAN ◽  
MELANIE CARE ◽  
DANNA A. SPEARS
Keyword(s):  
Heart Disease ◽  
Long Qt Syndrome ◽  
Qt Interval ◽  
Structural Heart Disease ◽  
Long Qt ◽  
Prolonged Qt Interval ◽  
Prolonged Qt ◽  
Qt Syndrome

scholarly journals A novel KCNH2 frameshift mutation (c.46delG) associated with high risk of sudden death in a family with congenital long QT syndrome type 2

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hyun Sok Yoo ◽  
Nancy Medina ◽  
María Alejandra von Wulffen ◽  
Natalia Ciampi ◽  
Analia Paolucci ◽  
...  
Keyword(s):  
Sudden Cardiac Death ◽  
Long Qt Syndrome ◽  
Cardiac Death ◽  
Frameshift Mutation ◽  
Alpha Subunit ◽  
Syndrome Type ◽  
Long Qt ◽  
Qt Syndrome ◽  
Congenital Long Qt Syndrome

Abstract Background The congenital long QT syndrome type 2 is caused by mutations in KCNH2 gene that encodes the alpha subunit of potassium channel Kv11.1. The carriers of the pathogenic variant of KCNH2 gene manifest a phenotype characterized by prolongation of QT interval and increased risk of sudden cardiac death due to life-threatening ventricular tachyarrhythmias. Results A family composed of 17 members with a family history of sudden death and recurrent syncopes was studied. The DNA of proband with clinical manifestations of long QT syndrome was analyzed using a massive DNA sequencer that included the following genes: KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2, ANK2, KCNJ2, CACNA1, CAV3, SCN1B, SCN4B, AKAP9, SNTA1, CALM1, KCNJ5, RYR2 and TRDN. DNA sequencing of proband identified a novel pathogenic variant of KCNH2 gene produced by a heterozygous frameshift mutation c.46delG, pAsp16Thrfs*44 resulting in the synthesis of a truncated alpha subunit of the Kv11.1 ion channel. Eight family members manifested the phenotype of long QT syndrome. The study of family segregation using Sanger sequencing revealed the identical variant in several members of the family with a positive phenotype. Conclusions The clinical and genetic findings of this family demonstrate that the novel frameshift mutation causing haploinsufficiency can result in a congenital long QT syndrome with a severe phenotypic manifestation and an elevated risk of sudden cardiac death.

Abstract 1778: Electrocardiographic and Genetic Screening for Long QT Syndrome: Results from a Prospective Study on 44,596 Neonates

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Marco Stramba-Badiale ◽  
Lia Crotti ◽  
Karine Goulene ◽  
Matteo Pedrazzini ◽  
Savina Mannarino ◽  
...  
Keyword(s):  
Sudden Death ◽  
Genetic Analysis ◽  
Prospective Study ◽  
Long Qt Syndrome ◽  
Qt Interval ◽  
Family Members ◽  
Long Qt ◽  
Prolonged Qt ◽  
Qt Syndrome ◽  
A Prospective Study

Background. The long QT syndrome (LQTS), a leading cause of sudden death under 20 years of age, is due to mutations in genes which encode ion channels involved in the control of ventricular repolarization. In a prospective study on 34,000 neonates we found that a prolonged QT interval was associated with a 41 times greater risk for sudden infant death syndrome (SIDS) and, recently, in a case-control study on 201 cases of SIDS we found disease-causing LQTS mutations in 9.5% of the victims. Based on these results the Italian Ministry of Health is considering the possibility of introducing in the National Health Service an electrocardiographic (ECG) screening program in the first month of life to identify infants affected by LQTS. A realistic assessment of the prevalence of infants with LQTS becomes necessary. Methods. An ECG was recorded in the first month of life in 44,596 neonates. The QT interval was measured and corrected for heart rate according to the Bazett’s formula (QTc). In the neonates with a markedly prolonged QT (QTc ≥ 470 msec) molecular screening of the LQTS genes was performed. Results. A QTc between 440 and 470 msec was observed in 611 neonates (1.4%). A QTc ≥ 470 ms was found in 31 neonates (0.07%). Genetic analysis was performed in 28/31 (90%) neonates and LQTS mutations were identified in 14 of them (50%): 8 were LQT1, 4 LQT2 and 2 LQT3. Besides one de novo mutation, all other cases were familial and genetic analysis identified additional family members (37/72, 51%) affected by LQTS who had not been previously diagnosed. Within these 28 infants QTc was longer in the positively genotyped neonates (493±22 vs 479±6 ms, p=0.037) and a LQTS mutation was identified in all the neonates (n=5) with a QTc > 496 ms. Conclusions. An ECG performed in the first month of life, with genetic analysis in selected cases, allows early diagnosis of infants with sporadic and familial forms of LQTS, thus leading to institution of effective therapies aimed at preventing sudden death either in infancy or later on in life, not only in the neonates but also in their affected family members. This study also provides a first data-based estimate of LQTS prevalence, likely to be between 1/3,000 and 1/2,500 live births.

scholarly journals Jervell and Lange-Nielsen syndrome. Family case (clinical observation)

2020 ◽  
pp. 88-92
Author(s):  
T.V. Tolstikova ◽  
◽  
L.V. Bregel ◽  
S.V. Czurkan ◽  
T.P. Marchuk ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Long Qt Syndrome ◽  
Qt Interval ◽  
Cardiac Death ◽  
Clinical Observation ◽  
Long Qt ◽  
Bilateral Hearing Loss ◽  
Life Threatening ◽  
Family Case ◽  
Qt Syndrome

A clinical family case of Jervell and Lange-Nielsen syndrome in 2 children is presented. Long QT syndrome is one of the leading causes of sudden cardiac death in children. Jervell and Lange-Nielsen syndrome is one of the most severe and rare types of long QT syndrome. Symptoms of the disease appear in infancy; they are characterized by a lengthening of QT interval on ECG, syncope as a result of life-threatening ventricular tachycardia and ventricular fibrillation, combined with congenital bilateral hearing loss.

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