Materiały źródłowe

• #1 Prevalence of the Congenital Long QT Syndrome

  https://pmc.ncbi.nlm.nih.gov/articles/PMC2784143/

  The prevalence of genetic arrhythmogenic diseases is unknown. For the long QT syndrome (LQTS), figures ranging from 1:20,000 to 1:5,000 were published but none was based on actual data. Our objective was to define the prevalence of LQTS. […] This study provides the first data-based estimate of the prevalence of LQTS among Caucasians. Based on the non-genotyped infants with QTc between 451 and 470 ms we advance the hypothesis that this prevalence might be close to 1:2,000. ECG-guided molecular screening can identify most infants affected by LQTS and unmask affected relatives, thus allowing effective preventive measures. […] Our data clearly indicate that at least 17 infants (16 because of disease-causing mutations and one because of clear-cut clinical diagnosis) among this cohort of 44,596 neonates are affected by LQTS. All of them are Caucasians. This indicates a prevalence among Caucasians of 1:2,534 (95% CI: 1:1,583 1:4,350). This prevalence is much higher than what has been previously suggested.

• #2 Congenital long QT syndrome | Orphanet Journal of Rare Diseases | Full Text

  https://ojrd.biomedcentral.com/articles/10.1186/1750-1172-3-18

  Congenital long QT syndrome (LQTS) is a hereditary cardiac disease characterized by a prolongation of the QT interval at basal ECG and by a high risk of life-threatening arrhythmias. Disease prevalence is estimated at close to 1 in 2,500 live births. […] Initially considered as a very rare condition, already in 1975 we suggested that LQTS „could be more unrecognized than rare”. When coming, however, to actual numbers everything seemed to go and the prevalence was assumed to be anywhere between 1/5,000 to 1/20,000, with most investigators settling for 1/10,000. Importantly, none of these estimates was based on actual data. […] The first data-driven indication of the prevalence of LQTS is coming from the largest prospective study of neonatal electrocardiography ever performed. An electrocardiogam (ECG) was recorded in 44,596 infants at 34 weeks of age. Among them, 1.4% had a corrected QT (QTc) interval between 440 and 469 ms and 0.7/1,000 had a QTc 470 ms, regarded as markedly prolonged by the European Task Force on Neonatal Electrocardiography.

• #3 Long QT Syndrome – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK441860/

  The prevalence of congenital causes, also known as Long QT syndrome (LQTS), is difficult to estimate but may be expected in 1 in 2,500 to 1 in 10,000 individuals. It is more common in females and usually presents with cardiac events in childhood, adolescence, or early adulthood. There are, however, case reports of it manifesting in the fifth decade of life. Family history is positive for Long QT syndrome in 40% and for sudden cardiac death in 30% of patients. Acquired causes are relatively more common than congenital causes. Some studies report the prevalence of QT prolongation in as many as 30% of patients in the intensive care unit.[7][8] […] Patients with a prolonged QT interval may be first identified by the primary care provider, internist, or pharmacist. It is important to refer these patients to the cardiologist/cardiac surgeon ASAP as the management is complex.

• #4 Long QT syndrome – Genomics Education Programme

  https://www.genomicseducation.hee.nhs.uk/documents/long-qt-syndrome/

  Long QT syndrome (LQTS) is an inherited heart rhythm problem, characterised by QT prolongation and T wave abnormalities on an ECG that are associated with tachyarrhythmias, most typically the ventricular tachycardia torsade de pointes (TdP). […] The prevalence of LQTS is estimated to be 1 in 2,500, and occurs across all ethnic groups. […] Approximately 75% of LQTS cases are caused by pathogenic variants in one of 15 known genes, most frequently with autosomal dominant inheritance, though there are also recessive forms. […] The diagnosis of LQTS is established in a proband with one or more of the following (Priori et al. 2013): A risk score of 3.5 in the absence of a secondary cause of QT prolongation. […] Molecular genetic diagnostic testing is usually performed by sequencing a panel of genes a panel test. Approximately 20-25% of families meeting clinical diagnostic criteria for LQTS do not have detectable pathogenic variants in a known gene, however relatives should still be considered at risk of sudden death in these families, and referred to an Inherited Cardiac Conditions (ICC) clinic for clinical evaluation.

• #5 Air Care Series: Long QT Syndrome — Taming the SRU

  https://www.tamingthesru.com/blog/air-care-series/long-qt-syndrome

  July 17, 2019

• #6 Congenital and Acquired Long QT Syndrome: A Pharmacist’s Perspective

  https://www.uspharmacist.com/article/congenital-and-acquired-long-qt-syndrome-a-pharmacists-perspective

  Long QT syndrome (LQTS), in which cardiac repolarization is delayed following a heartbeat, can be measured by ECG. Universal ECG screening is not standard practice in the United States, and many children with congenital LQTS go undiagnosed. […] LQTS may be inherited or acquired. Acquired LQTS, which is usually drug-induced, is more common than inherited LQTS. The prevalence of inherited LQTS in the U.S. is estimated to be one in 2,000 to 2,500 live births. […] LQTS can be detected in children through ECG, although widespread routine screening in asymptomatic patients is not currently recommended in the U.S. The prognosis for untreated patients presenting with syncope is a 20% chance of death after 1 year, and a 50% chance within 10 years. […] As of early 2014, only one country worldwide was found to require universal ECG screenings. For more than 25 years, Italy has mandated medical screening for any individual wishing to participate in competitive sports. […] A recent meta-analysis estimated that, at the maximum accuracy point, the number needed to screen to detect one case of LQTS by ECG exceeded 16,000. […] The FDA issued a warning in response to a 2012 study that reported increased CV mortality with azithromycin versus amoxicillin use.

• #7 Macromo | Long QT Syndrome

  https://insider.macromo.com/articles/long-qt-syndrome

  Long QT syndrome is often divided into two big categories: congenital and acquired. […] Unlike other less common channelopathies, the estimated prevalence of congenital LQTS is at least 1 in 2000. This prevalence is based on a study of 44,000 newborns that combined ECG findings and genetic testing, and refers to newborns who are positive for both a genetic variant and a truly prolonged QT interval. […] Based on available data and statistics, the risk of developing congenital or acquired long QT syndrome or its symptoms increases in the presence of the following: Gender – men are at higher risk during childhood and women from teenage life onward. […] Genetic testing allows us to detect whether you have the predisposition to develop this disease and therefore directs us to take steps toward prevention, monitoring, and possible treatment options.

• #8 Congenital long QT syndrome | Orphanet Journal of Rare Diseases | Full Text

  https://ojrd.biomedcentral.com/articles/10.1186/1750-1172-3-18

  As almost 50% of the infants with QTc 470 ms (0.7/1,000) are affected by LQTS, and as at least some (number being currently defined by extensive molecular screening) of the infants with QTc between 440 and 469 ms are also likely to be affected, it follows that the prevalence of LQTS must be close to 1/2,500 at least. This is probably a bit of an underestimate because we have postulated first and demonstrated later that there is a significant number of silent mutation carriers (QTc 440 ms) that actually ranges between 10% and 36% according to genotype. For the first time the prevalence of a cardiac disease of genetic origin has been quantified on the basis of actual data.

• #9 Diagnosis, management and therapeutic strategies for congenital long QT syndrome | Heart

  https://heart.bmj.com/content/108/5/332

  However, further optimisation of treatment strategies is pertinent, in particular in two specific patient categories. […] Finally, despite all progress in genetic screening methods, the yield of finding a potential pathogenic variant in a LQTS patient with a clear phenotype is at most 75%-80%. […] Important additional scientific inquiries in this field are the unravelling of the genotype in the 25%-30% genotype elusive cases and the role of additional genetic and other factors in determining the arrhythmia risk.

• #10 Clinical and Genetic Characteristics of Long QT Syndrome – Revista Española de Cardiología (English Edition)

  https://www.revespcardiol.org/en-clinical-and-genetic-characteristics-of–articulo-13109918

  Long QT syndrome displays great genetic heterogeneity. More than 500 mutations distributed in 10 genes have been described in this condition: KCNQ1, HERG, SCN5A, KCNE1, KCNE2, ANKB, KCNJ2, CACNA1, CAV3, and SCN4B. […] A genetic diagnosis cannot be established in 25%-30% of patients. […] The evolution of LQTS varies and is influenced by the duration of the QTc interval, environmental factors, age, genotype, and response to treatment. […] Long QT syndrome should be considered high-risk when it is associated with the following: 1. Congenital deafness (Jervell-Lange-Nielsen syndrome). 2. Recurrent syncope due to malignant ventricular tachyarrhythmia. 3. Family history of sudden death. 4. QTc500 ms. 5. 2:1 atrioventricular block. 6. T wave electric alternans. 7. LQTS3 genotype. […] The study by Priori et al performed in 647 patients showed that the probability of presenting a major event (syncope, cardiac arrest, sudden death) before 40 years of age is high (50%) when QTc is 500 ms in LQTS1, LQTS2, and in males with LQTS3. […] Symptomatic patients who do not receive treatment have a yearly mortality rate of 20% and 10-year mortality of 50% after a first event of ventricular arrhythmia.

• #11 Long QT Syndrome: Practice Essentials, Background, Etiopathophysiology

  https://emedicine.medscape.com/article/157826-overview

  Long QT syndrome (LQTS) remains an underdiagnosed disorder, especially because some individuals may LQTS gene mutation carriers who have a normal QTc duration. The prevalence of LQTS is difficult to estimate. However, LQTS may be expected to occur in the range of 1 in 2,000 to 1 in 5,000 individuals. […] The occurrence of long QT syndrome internationally is similar to that in the United States. […] Newly diagnosed cases of LQTS are more prevalent in female patients (60-70% of cases) than in male patients. The female predominance may be related to the relatively prolonged QTc (as determined by using the Bazett formula) in women compared to men and to a relatively higher mortality rate in young men. In women, pregnancy is not associated with an increased incidence of cardiac events, whereas the postpartum period is associated with a substantially increased risk of cardiac events, especially in the subset of patients with LQT2. Cardiac events have been highly correlated with menses.

• #12 Clinical and genetic profile of congenital long QT syndrome in Hong Kong: a 20-year experience in paediatrics | HKMJ

  https://www.hkmj.org/abstracts/v24n6/561.htm

  Congenital long QT syndrome (LQTS) is a genetically transmitted cardiac channelopathy that can lead to sudden cardiac death. This study aimed to report the clinical and genetic characteristics of all young patients diagnosed with LQTS in the only tertiary paediatric cardiology centre in Hong Kong. […] The prevalence of childhood LQTS was estimated to be 1:2000 in an Italian birth cohort. In a recent Japanese study, the estimated probability of diagnosing LQTS was 1:3300 in children aged 6 years and 1:1000 in those aged 12 years. Our results indicate that the prevalence of diagnosed LQTS in Hong Kong children was less than 1:10 000, suggesting an underdiagnosis of the condition. This is likely due to under-recognition of symptomatic LQTS in young patients who were treated for recurrent seizure and unexplained syncope. Without an ECG screening programme, many asymptomatic LQTS children also remain undiagnosed. The lack of comprehensive screening for family members of adult LQTS probands is another reason for underdiagnosis, as only two children from a single family were referred to us from adult cardiologists over the 20-year study period.

• #13 Acquired Long QT Syndrome and Electrophysiology of Torsade de Pointes | AER Journal

  https://www.aerjournal.com/articles/acquired-long-qt-syndrome-and-electrophysiology-torsade-de-pointes?language_content_entity=en

  The overall incidence of drug-induced LQTS in a given population is difficult to estimate. […] European pharmacovigilance centres in Sweden, Germany and Italy have found an annual reporting rate of drug-induced LQTS or TdP of approximately 0.8 to 1.2 per million person-years. […] An epidemiological study of drug-induced LQTS in Germany found the reporting rate for symptomatic acquired LQTS to be 2.5% per million person-years for men and 4.0% per million person-years for women, with 60% attributed to drugs. […] QT prolongation is one of the most common reasons for drug withdrawal from the market, despite the fact that these drugs may be beneficial for certain patients and not harmful in every patient. […] Since 1989, 14 clinically important drugs have been removed from the market due to TdP, and development of an unknown number has been stopped, due to concerns that these might pose a risk of causing QT prolongation and TdP. […] In the past decade, hERG channel-mediated cardiac toxicity, manifested as QT interval prolongation, has become a major safety issue in drug development, superseding liver injury as the main cause of drug withdrawals.

• #14 Long QT Syndrome: Practice Essentials, Background, Etiopathophysiology

  https://emedicine.medscape.com/article/157826-overview

  Patients with LQTS usually present with cardiac events (eg, syncope, aborted cardiac arrest, sudden death) in childhood, adolescence, or early adulthood. However, LQTS has been identified in adults as late as in the fifth decade of life. The risk of death from LQTS is higher in boys than in girls younger than 10 years; the risk is similar in male and female patients thereafter.

• #15 Diagnosis, management and therapeutic strategies for congenital long QT syndrome | Heart

  https://heart.bmj.com/content/108/5/332

  In this review, we summarise the current evidence available on the diagnosis, clinical management and therapeutic strategies in LQTS. […] The age of onset of arrhythmias is typically younger in LQT1 patients and in particular LQT1 males are at risk, whereas most LQT2 and LQT3 patients who become symptomatic experience their first symptoms around puberty and here particular females are at risk. […] Because of the genotype-specific features with impact on prognosis and therapy, genetic testing has become an integral part of the diagnosis and management of LQTS patients. […] The cornerstone of management of LQTS patients is -blocker therapy. […] New pharmacological therapy is emerging, but the target population becomes more and more specific. […] The advancement of knowledge in the LQTS field has been tremendous with the change from the description of individuals with a electrocardiographic curiosity, many of whom died suddenly, to a genotype-specific approach of the different disease subtypes.

• #16 Congenital long QT syndrome during and after pregnancy

  https://www.uscjournal.com/articles/management-long-qt-syndrome-women-during-and-after-pregnancy?language_content_entity=en

  However, there are only limited reviews guiding management of the pregnant woman with LQTS. […] This comprehensive review highlights important information to assist cardiologists in management of these women before, during, and after pregnancy. […] Pregnant women with LQTS benefit from multidisciplinary care from electrophysiologists, general adult cardiologists, obstetricians, maternal-fetal medicine specialists, fetal cardiologists, anesthesiologists, and genetic counselors. […] The risk of LQTS-related cardiac events decreases during pregnancy compared with the time period before a woman’s first conception, but increases significantly in the 9-month postpartum period, and frequency of events returns to pre-pregnancy levels after this period. […] Treatment with a -blocker is indicated to reduce risk of cardiac events and sudden cardiac death.

• #17 Congenital long QT syndrome during and after pregnancy

  https://www.uscjournal.com/articles/management-long-qt-syndrome-women-during-and-after-pregnancy?language_content_entity=en

  Guidelines for management of ventricular arrhythmias and prevention of sudden cardiac death strongly recommend that in women with LQTS, a -blocker should be continued during pregnancy and the postpartum period regardless of symptoms, including while breastfeeding. […] In at least one study, increased risk for cardiac events in the high-risk postpartum period was significantly reduced by -blockers. […] Women with LQTS have an increased risk for cardiac events, including sudden cardiac death, in the first 9 months following delivery. […] In one retrospective analysis of 111 probands with LQTS, 10% experienced their first cardiac event in the postpartum period and were more likely to have multiple events. […] Therefore, it is essential for high-risk women with LQTS to continue taking -blockers throughout the postpartum period as first-line, protective therapy for which the benefits outweigh risks of treatment.

• #18 Congenital long QT syndrome: Epidemiology and clinical manifestations – UpToDate

  https://www.uptodate.com/contents/congenital-long-qt-syndrome-epidemiology-and-clinical-manifestations

  Long QT syndrome (LQTS) is a disorder of ventricular myocardial repolarization characterized by a prolonged QT interval on the electrocardiogram (ECG) that can lead to symptomatic ventricular arrhythmias and an increased risk of sudden cardiac death (SCD). LQTS may be congenital or acquired. Likely pathogenic or pathogenic variants in at least 17 genes have been identified thus far in patients with congenital LQTS. However, pathogenic variants in the three canonical genes, KCNQ1 (LQT1), KCNH2 (LQT2), and SCN5A (LQT3), account for approximately 80 to 90 percent of all congenital LQTS cases, with pathogenic variants in the minor LQTS-susceptibility genes contributing approximately 5 percent. An estimated 10 percent of patients satisfying a robust clinical diagnosis of LQTS will have a negative LQTS genetic test. Acquired LQTS usually results from undesired QT prolongation and potential for QT-triggered arrhythmias by either QT-prolonging disease states, QT-prolonging medications, or QT-prolonging electrolyte disturbances. While disease-causative variants in numerous genes have been identified in patients with congenital LQTS, two clinical phenotypes have been described that differ in the type of inheritance and the presence or absence of sensorineural hearing loss: The more common autosomal dominant form, originally named the Romano-Ward syndrome, has a purely cardiac phenotype of QT prolongation and QT-triggered cardiac events. The autosomal recessive form, originally named the Jervell and Lange-Nielsen syndrome, is associated with LQTS and sensorineural deafness, and a more malignant clinical course.

• #19 Congenital long QT syndrome: Epidemiology and clinical manifestations – UpToDate

  https://www.uptodate.com/contents/congenital-long-qt-syndrome-epidemiology-and-clinical-manifestations/print

  Long QT syndrome (LQTS) is a disorder of ventricular myocardial repolarization characterized by a prolonged QT interval on the electrocardiogram (ECG) that can lead to symptomatic ventricular arrhythmias and an increased risk of sudden cardiac death (SCD). […] LQTS may be congenital or acquired. […] Likely pathogenic or pathogenic variants in at least 17 genes have been identified thus far in patients with congenital LQTS. […] However, pathogenic variants in the three canonical genes, KCNQ1 (LQT1), KCNH2 (LQT2), and SCN5A (LQT3), account for approximately 80 to 90 percent of all congenital LQTS cases. […] An estimated 10 percent of patients satisfying a robust clinical diagnosis of LQTS will have a negative LQTS genetic test. […] Acquired LQTS usually results from undesired QT prolongation and potential for QT-triggered arrhythmias by either QT-prolonging disease states, QT-prolonging medications, or QT-prolonging electrolyte disturbances.

• #20 Long QT syndrome with mutations in three genes: A rare case | Revista Portuguesa de Cardiologia (English edition)

  https://www.revportcardiol.org/en-long-qt-syndrome-with-mutations-articulo-S217420491500077X

  Genetic testing, which identifies the mutation responsible in 50-70% of cases, is important to confirm the diagnosis, identify asymptomatic carriers, stratify risk for arrhythmic events and provide a basis for genetic counseling. […] Our patient presented mutations in three different genes. […] LQTS is a rare hereditary disease in patients without structural heart disease that is associated with a high risk of malignant VT and sudden death.

• #20 Long QT syndrome with mutations in three genes: A rare case | Revista Portuguesa de Cardiologia (English edition)

  https://www.revportcardiol.org/en-long-qt-syndrome-with-mutations-articulo-S217420491500077X

  Congenital long QT syndrome (LQTS) is a rare hereditary disease, with an incidence of 1 in 2000, characterized by prolonged ventricular repolarization and malignant ventricular tachyarrhythmias. […] LQTS is a genetic disease characterized by significant prolongation of the QT interval, predisposing to ventricular arrhythmias and manifesting clinically with syncope, seizures or sudden death in individuals with structurally normal hearts. […] According to the HRS/EHRA/APHRS expert consensus statement on inherited primary arrhythmia syndromes, LQTS is diagnosed: (a) in the presence of an LQTS risk score 3.5 in the absence of a secondary cause for QT prolongation and/or (b) in the presence of a pathogenic mutation in one of the LQTS genes or (c) in the presence of a QTc 500 ms in repeated 12-lead ECGs.

• #21 The long QT syndrome family of cardiac ion channelopathies: A HuGE review | Genetics in Medicine

  https://www.nature.com/articles/gim200626

  Long QT syndrome (LQTS) refers to a group of channelopathies disorders that affect cardiac ion channels. […] The genetic epidemiology of both forms can vary with subpopulation depending on the allele, but as a whole, LQTS appears in every corner of the globe. […] Many polymorphisms, such as HERG P448R and A915V in Asians, and SCN5A S1102Y in African Americans, show racial-ethnic specificity. […] Studies have generally demonstrated greater QT prolongation and more severe outcomes among adult females. […] The public health importance of LQTS is highlighted by the fact that it can result in sudden death, causing as many as 3,000 unexpected deaths in children and young adults annually in the U.S. […] In the absence of treatment, 6 to 13% of affected individuals succumb to cardiac arrest or sudden cardiac death (SCD) before the age of 40 years.

• #22 Congenital long QT syndrome: Epidemiology and clinical manifestations – UpToDate

  https://www.uptodate.com/contents/congenital-long-qt-syndrome-epidemiology-and-clinical-manifestations/print

  While disease-causative variants in numerous genes have been identified in patients with congenital LQTS, two clinical phenotypes have been described that differ in the type of inheritance and the presence or absence of sensorineural hearing loss. […] The more common autosomal dominant form, originally named the Romano-Ward syndrome, has a purely cardiac phenotype of QT prolongation and QT-triggered cardiac events. […] The autosomal recessive form, originally named the Jervell and Lange-Nielsen syndrome, is associated with LQTS and sensorineural deafness, and a more malignant clinical course.

• #23 Orphanet: Congenital long QT syndrome

  https://www.orpha.net/en/disease/detail/768

  The most prevalent form, Romano-Ward syndrome (RWS), has a prevalence close to 1/2,500 live births. […] The other forms of familial LQTS are extremely rare.

• #24 Long QT Syndrome | Boston Children’s Hospital

  https://www.childrenshospital.org/conditions/long-qt-syndrome

  Long QT Syndrome (LQTS) is an inherited condition that affects the hearts electrical rhythm and can cause fast, erratic heartbeats. […] LQTS causes approximately 3,000 to 4,000 sudden deaths of children and young adults each year in the United States. […] LQTS is fairly rare. It is estimated that about 1 in every 2,500 children born have the condition. […] Early diagnosis of LQTS is important. The Center for Cardiovascular Genetics at Boston Childrens Hospital specializes in family based services for children with inherited arrhythmias like long QT syndrome. The program meets with and assesses entire families all at once, usually in one day. Our specialists use genetic testing to identify all family members at risk of developing the condition.

• #25

  https://www.gehealthcare.com/insights/article/concerns-and-challenges-with-long-qt-in-children-and-teens?srsltid=AfmBOooxCxsf8NAS-Tk5XAbCHkSZUfCKZ194ayvxNMoHuizKz0lCGVuU

  Long QT in children and teens is a particularly concerning condition characterized by a prolonged QT interval and arrhythmias stemming from torsades de pointes, which can cause syncope and may progress to ventricular fibrillation, resulting in cardiac arrest or sudden death. […] The true prevalence of long QT syndrome (LQTS), which is either congenital or acquired, is unknown because the condition often goes unnoticed. One widely cited study in Circulation from 2009 estimated a prevalence of congenital LQTS of about 1 in 2,000. The National Heart, Lung, and Blood Institute (NHLBI) says experts estimate that LQTS can be found in about 1 in 7,000 people and that it causes 3,000 to 4,000 sudden deaths in American children and young adults each year. Cardiac arrest or sudden death will be the first indication of a problem in about 10% of those who are affected.

• #26 Long QT Syndrome | 5-Minute Pediatric Consult

  https://peds.unboundmedicine.com/pedscentral/view/5-Minute-Pediatric-Consult/617288/all/Long_QT_Syndrome?q=sotalol

  Prevalence of LQTS is estimated to be approximately 1 in 2,500. […] Cardiac events occur in ~50% of congenital LQTS patients; most occur in preteens, adolescents, and young adults.

• #27 Genetic testing for – Blueprint Genetics

  https://blueprintgenetics.com/tests/panels/cardiology/long-qt-syndrome-lqts-panel/

  Long QT syndrome (LQTS) can present as unexpected fainting, ventricular arrhythmias and sudden cardiac death in patients with structurally normal hearts. Sudden death is the first symptom in 10%-15% of long QT syndrome patients. The prevalence of LQTS is estimated to be 1:3,000 and occurs in all ethnicities. Long QT syndrome causes thousands of deaths annually in Europe and North America. The disorder typically manifests in patients younger than 40 years of age and sometimes as early as infancy. Clinical diagnosis is based on patients history, ECG, and family history. Genetic testing is an increasingly important component of the evaluation of LQTS patients. Mutations in cardiac ion-channels can be detected in 75% of patients with clinical diagnosis of LQTS. […] The performance metrics listed below are from an initial validation performed at our main laboratory in Finland. The performance metrics of our laboratory in Marlborough, MA, are equivalent.

• #28 Long QT Syndrome: Symptoms & Treatment

  https://my.clevelandclinic.org/health/diseases/17183-long-q-t-syndrome-lqts

  Long QT syndrome is rare. About 1 in 2,000 people in the United States have long QT syndrome. […] Long QT syndrome is a medical condition that people can pass on from generation to generation. You should get a genetic screening if you have a first-degree relative with long QT syndrome. First-degree relatives are your parents, siblings and children. […] Long QT syndrome can lead to Torsades de Pointes. This is a life-threatening arrhythmia that can lead to sudden death. […] Healthcare providers can diagnose long QT syndrome during a routine electrocardiogram (EKG). To make a diagnosis, they measure the QT interval on the EKG. If your QT interval is longer than 450 milliseconds, you may have long QT syndrome. […] Long QT syndrome treatments include medications, devices or surgery that help you manage symptoms and prevent sudden death. Treatments dont provide a cure, but can keep you safer from abnormal heart rhythms. […] With the right treatment, people with long QT syndrome have a death rate of about 1%. Without treatment, the prognosis is poor. Up to 21% of untreated people with symptoms die within a year after they start fainting.

• #29

  https://link.springer.com/article/10.1007/s00246-019-02151-x

  Long QT syndrome (LQTS), an inherited primary arrhythmia syndrome, demonstrates a prevalence of 1 out of every 2000 healthy live births. […] Mortality in the current era for patients with LQTS with appropriate medical therapy is now 0.3%. […] LQTS is diagnosed by careful clinical and family history including symptoms of syncope, anoxic seizures, or, rarely, palpitations and through targeted investigations including ECGs, 24-h Holter recording analysis, and exercise stress testing. […] Genetic screening for LQTS mutations also identifies asymptomatic and phenotype-negative LQTS individuals that might otherwise come to harm from their disease where they are exposed to additional exogenous risk factors including QT-prolonging pharmaceutical drugs. […] Current standard of care therapy for LQTS is the prescription of non-cardioselective beta-blockers.

• #30 The long QT syndrome family of cardiac ion channelopathies: A HuGE review | Genetics in Medicine

  https://www.nature.com/articles/gim200626

  The frequency of cardiac events (syncope, aborted cardiac arrest and sudden death) tends to be higher in individuals with LQT2 mutations than in those with LQT1 or LQT3 mutations. […] A clinical scoring system (where 3 points = an item indicating greatest likelihood of LQTS, such as QTc 480 milliseconds; and 0.5 points = an item indicating least likelihood, such as congenital deafness), based on personal and family history, symptomatology, and ECG has been developed. […] Genetic testing has so far largely been relegated to the research setting, making the phenotypic and nonmolecular genotypic tests cited above the mainstay of clinical risk assessment. […] LQTS population screening programs are shaped by existent facilities and whether particular highly prevalent mutations have been identified within a given country.

• #31 The long QT syndrome: Half a century of electrophysiology | British Columbia Medical Journal

  https://bcmj.org/articles/long-qt-syndrome-half-century-electrophysiology

  With treatment this figure is reduced approximately tenfold. […] While the frequency of events is higher in LQT1 and LQT2 and in patients with longer QTc, the mean QTc and the lethality of events are highest in LQT3. […] Beta-blockers form the mainstay of therapy in long QT syndrome. […] The mortality has been significantly reduced using this modality of therapy alone. […] With the recognition of LQTS subtypes, we may see the emergence of mutation specific treatments. […] For example, the treatment of patients with sodium channel defects (LQT3) with the sodium channel blocking agent flecainide has shown some promise in a small group of patients. […] In some patients, pacing may be beneficial. […] This should be viewed as an adjunctive therapy and pacing these patients may require complex algorithms to eliminate the post-extrasystolic pauses that may lead to torsade de pointes.

• #32 Long QT syndrome is associated with an increased burden of diabetes, psychiatric and neurological comorbidities: a nationwide cohort study | Open Heart

  https://openheart.bmj.com/content/6/2/e001161

  In this nationwide cohort, patients with LQTS had a significantly increased burden of diabetes, neurological and psychiatric comorbidities, compared with the background population. […] LQTS patients had a higher prevalence of diabetes (3.7% vs 1.8 %, p=0.011) […] LQTS patients had a higher prevalence of psychiatric disorders overall (13.0% vs 9.1%, p=0.01) […] LQTS patients had a higher prevalence of neurological disorders (22.0% vs 13.2%, p0.001), largely driven by epilepsy (6.7% vs 1.6%, p0.001). […] Our data support that LQTS may be considered a multiorgan disease and suggest that patient management should be adjusted accordingly.

• #33 The long QT syndrome: Half a century of electrophysiology | British Columbia Medical Journal

  https://bcmj.org/articles/long-qt-syndrome-half-century-electrophysiology

  ECGs should be obtained from the immediate family, although approximately 40% of new cases are sporadic. […] However, 5% to 10% of both genotyped and symptomatic family members have a normal QT interval. […] Due to the difficulty in making a diagnosis in some patients, Schwartz proposed a scoring system combining ECG and clinical data. […] While this is helpful in some cases, it does little to sort out the patients with a borderline prolongation of the QTc. […] In most patients a 12-lead ECG suffices; however, in some patients additional testing will increase the likelihood of making the correct diagnosis. […] Sometimes, several ECGs are required before recording the prolonged QT interval. […] The QTc as derived by Bazetts formula is generally used, as determined by dividing the measured QT by the square root of the R-R interval.

• #34 The long QT syndrome: Half a century of electrophysiology | British Columbia Medical Journal

  https://bcmj.org/articles/long-qt-syndrome-half-century-electrophysiology

  Holter monitoring is sometimes useful in detecting prolongation of the QT interval and T wave changes. […] The T wave may change in amplitude and in direction from beat to beat, a phenomenon known as T wave alternans. […] The Holter monitor is also an important test for detecting occult arrhythmias. […] Sinus bradycardia is common, even without beta-blockade, and has been recognized in the fetus. […] The presentation may be that of profound bradycardia due to extreme prolongation of the QTc leading to pseudo heart block. […] Exercise testing is often used to document peak heart rate, inducibility of arrhythmias, and to determine the QT interval in the recovery phase of the test, where QT prolongation may be most marked. […] The untreated mortality of long QT syndrome has been estimated to be 50% over 10 years.

• #35 Long QT Syndrome – Melbourne Heart Rhythm

  https://www.melbourneheartrhythm.com.au/learn/conditions/53-long-qt-syndrome

  The main value of genetic testing lies in family screening. Following the identification of a patient (so called “proband”) who unequivocally has LQTS, molecular diagnosis is then sought through screening the known genes. […] All patients with LQTS should avoid medications contra-indicated in LQTS. A list of these drugs can be found on the net under ‘LQT drugs’ Those with a long QT interval (>500ms), especially young males and adult females need to be treated much as someone who has already presented with syncope.

• #36 Congenital Long QT Syndrome in Children and Adolescents: A General Overview

  https://www.mdpi.com/2227-9067/11/5/582

  Long QT syndrome would appear to be a suitable disease for universal screening because of its relatively high incidence in the general population (1:2000–2500 healthy live births), the fact that sudden cardiac death is a presenting symptom in around 12% of cases, and the safety, effectiveness, and cost-effectiveness of treatment with β-blockers.

• #37 Long QT Syndrome – SADS Foundation

  https://sads.org/sads-conditions/long-qt-syndrome/

  We estimate that at least 1 in 2000 people in the United States have congenital long QT syndrome (LQTS). […] LQTS is an inherited genetic condition, so if someone in your family is diagnosed with LQTS, it is extremely important that the rest of your family be tested for the syndrome. […] If your story is suspicious, a QT exceeding 470 ms in males and 480 ms in females is sufficient evidence for a diagnosis of probable LQTS, assuming that medications which prolong the QT interval or other QT-prolonging medical conditions have been ruled out. […] If youre symptomatic, you should receive treatment, and most children and young adults should be treated even if they do not have symptoms. […] It is very important that the medication be taken every day, and not be missed or omitted.

• #38 Clinical and genetic profile of congenital long QT syndrome in Hong Kong: a 20-year experience in paediatrics | HKMJ

  https://www.hkmj.org/abstracts/v24n6/561.htm

  Our study demonstrated the high yield of genetic testing and the importance of genetic information in predicting the prognosis of patients with LQTS and guiding their treatment. Early identification of affected family members through cascade screening of mutated gene was also demonstrated. We hope that public genetic services can continue to develop, to enable genetic testing to be offered to all patients with suspected channelopathies. We also advocate the establishment in Hong Kong of inherited arrhythmia clinics or cardiac genetic clinics in the public sector, as implemented in many other countries. Such clinics have proven effectiveness in reducing sudden cardiac death associated with inherited arrhythmia syndrome.

• #39 New Insights Into the Long-QT Syndrome – Revista Española de Cardiología (English Edition)

  https://www.revespcardiol.org/en-new-insights-into-long-qt-syndrome-articulo-13109909

  Another recent comprehensive postmortem study performed genetic testing in 49 sudden unexplained death (SUD) victims with an average age of death of 14.2 years. […] Given the role of the identification of the genetic substrate for LQTS patients’ management, the most important challenge in the field is now that of increasing access to and reimbursement of genetic analysis for LQTS.

• #39 New Insights Into the Long-QT Syndrome – Revista Española de Cardiología (English Edition)

  https://www.revespcardiol.org/en-new-insights-into-long-qt-syndrome-articulo-13109909

  Long QT Syndrome (LQTS) is an arrhythmogenic disease in which prolongation of cardiac repolarization alters electrical stability of the heart predisposing affected individuals to cardiac arrest. […] Autosomal dominant LQTS occurs with an estimated frequency of about 1 in 5000 people in the general population. […] The J-LN is far less common with an estimated incidence of 1.6 to 6 cases per million. […] Based on the current knowledge about the molecular substrate of LQTS, 70% of Romano-Ward probands can be successfully genotyped by standard methods. […] Recently, we reported the feasibility of an effective alternative strategy that may help bring genotyping closer to routine clinical practice. […] A molecular study in 201 Norwegian sudden infant death syndrome (SIDS) victims showed that genetic variants in LQTS genes are present in 9.5% of SIDS victims.

• #40 Prevalence of the Congenital Long QT Syndrome

  https://pmc.ncbi.nlm.nih.gov/articles/PMC2784143/

  The present findings provide the first data-based estimate of the prevalence of a clinically important arrhythmogenic disease of genetic origin, the long QT syndrome (LQTS). Until now the prevalence of these diseases, regarded as rare, was simply unknown despite the fact that articles and textbooks often mentioned one or another estimate but without support from objective data. Our own data, based on ECG-guided identification of disease-causing mutations, indicate that among Caucasians the prevalence of LQTS is at least of 1:2,534 apparently healthy live births. This finding has direct implications for the early detection of LQTS. […] Besides providing the first direct evidence on the prevalence of LQTS, much higher than what previously postulated, these findings carry clinically relevant implications. One is that infants with a QTc 460 ms in the first month of life and whose QT interval remains prolonged at one year have a 90% probability to carry a LQTS-causing mutation. Also, whereas genetic screening should be immediately performed in all infants with a QTc 485 ms, the normalization within a year for 75% of the infants with an initial QTc between 460 and 485 ms suggests – unless one of the parents shows QT prolongation – to postpone the genetic screening for this group until the end of the first year of life. This simple measure will reduce both costs and unnecessary anxiety. […] ECG-guided molecular screening can identify most infants affected by LQTS and unmask affected relatives, thus allowing the early institution of effective preventive measures.

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