Humans ; Diagnosis, Differential ; Long QT Syndrome/genetics* ; Syncope/diagnosis* ; Epilepsy/diagnosis* ; Electrocardiography

Humans ; Mutation, Missense ; KCNQ1 Potassium Channel/genetics* ; Long QT Syndrome/genetics* ; Phenotype ; Mutation ; Pedigree

Humans ; Mutation, Missense ; KCNQ1 Potassium Channel/genetics* ; Long QT Syndrome/genetics* ; Phenotype ; Mutation ; Pedigree

Objective: To investigate the long-term efficacy and safety of left cardiac sympathetic denervation(LCSD) for long QT syndrome(LQTS) patients with either recurrence on drug therapy intolerance/refusal. Methods: This study was a retrospective cohort study. The cases selected from 193 patients with LQTS who were enrolled in the Chinese Channelopathy Registry Study from November 1999 to November 2012. This study selected 28 LQTS patients with either recurrence on drug therapy intolerance/refusal and underwent LCSD surgery in the Peking University People's Hospital or Beijing Tongren Hospital. The patients were allocated into 3 groups: high-risk group(n=13, baseline QTc ≥550 ms or symptomatic in the first year of life or highly malignant genetics); intermediate-risk group(n=10, 500 ms≤baseline QTc<550 ms, symptomatic after the first year and without highly malignant genetics); low-risk group(n=5, baseline QTc<500 ms, symptomatic after the first year and without highly malignant genetics). LCSD was performed with the traditional supraclavicular approach or video assisted thoracoscopic surgery (VATS). Patients were regularly followed up until 20 years after the surgery. Data were collected before and 1 year after surgery and at the last follow-up. Patients' electrocardiograph(ECG), cardiac events and surgery-related complications were recorded. Kaplan-Meier survival analysis was used to determine the cardiac event-free survival based on different risk stratification and genotypes. Results: A total of 28 LQTS patients, aged 20.5 (15.0, 37.5) and underwent LCSD surgery, were enrolled in this study, including 23(82.1%) women. There were 11(39.3%) patients treated with traditional approach while 17(60.7%) with VATS-LCSD. There were 19(67.9%) patients had positive genetic test results, including 4 LQT1, 12 LQT2, 1 LQT1/LQT2 mixed type, and 2 Jervell-Lange-Nielsen (JLN) syndrome. The median follow-up period was 189.3(138.7, 204.9) months. The dropout rate was 10.7%(3/28) while 3 patients in the intermediate-risk group were lost to follow-up. Horner syndrome occurred in 1 patient (in the high-risk group). Sudden cardiac deaths were observed in 3 (12.0%) patients (all in the high-risk group), and 12 patients (48.0%) had syncope recurrences (2 in low-risk group, 3 in intermediate-risk group and 7 in high-risk group). A significant reduction in the mean yearly episodes of cardiac events was observed, from (3.5±3.3) before LCSD to(0.2±0.1) at one year after LCSD and (0.5±0.8) at last follow up(P<0.001). The mean QTc was shortened from (545.7±51.2)ms before the surgery to (489.0±40.1)ms at the last follow-up (P<0.001). Among the 20 patients with basic QTc ≥500 ms and completing the follow-up, the QTc intervals of 11(55.0%) patients were shortened to below 500 ms. The event free survival rates for any cardiac events after LCSD decreased sequentially in the low-, intermediate- and high-risk groups, and the difference was statistically significant (χ²=7.24, log-rank P=0.026). No difference was found in the event free survival rates among LQT1, LQT2 and undefined gene patients (χ²=5.20, log-rank P>0.05). Conclusions: LCSD surgery can reduce the incidence of cardiac events and shorten the QTc interval in patients with LQTS after the long-term follow-up. LCSD surgery is effective and safe for patients with LQTS ineffective or intolerant to drug therapy. However, high-risk patients are still at a high risk of sudden death after surgery and should be actively monitored and protected by combined therapies.
Electrocardiography ; Female ; Heart ; Humans ; Long QT Syndrome ; Male ; Retrospective Studies ; Sympathectomy/methods*

Andersen Syndrome/genetics* ; Humans ; Syncope ; Tachycardia, Ventricular

Objective: To evaluate the main triggers of recurrent cardiac events in patients with symptomatic congenital long QT syndrome (cLQTS). Methods: In this retrospective case analysis study, clinical characteristics were reviewed from 38 patients with recurrent cardiac events after first visit out of 66 symptomatic cLQTS patients. General clinical data such as gender, age, clinical presentation, family history and treatment were collected, auxiliary examination results such as electrocardiogram and gene detection were analyzed. LQTS-related cardiac events were defined as arrhythmogenic syncope, implantable cardioverter defibrillator (ICD) shock, inappropriate ICD shock, aborted cardiac arrest, sudden cardiac death or ventricular tachycardia. Results: A total of 38 patients with recurrent symptoms were enrolled in this study, including 30 females (79%) and 14 children (37%). The average age of onset was (15.6±14.6) years, and the recurrence time was (3.6±3.5) years. Subtype analysis showed that there were 11 cases (29%) of LQT1 (including 2 cases of jervel-Lange Nielson syndrome), 19 cases (50%) of LQT2, 5 cases (13%) of LQT3 and 3 cases (8%) of other rare subtypes (1 LQT5, 1 LQT7 and 1 LQT11) in this patient cohort. LQT1 patients experienced recurrent cardiac event due to drug withdrawal (6 (55%)), specific triggers (exercise and emotional excitement) (4 (36%)) and medication adjustment (1 (9%)). For LQT2 patients, main triggers for cardiac events were drug withdrawal (16 (84%)), specific triggers (shock, sound stimulation, waking up (6 (32%)). One patient (5%) had recurrent syncope after pregnancy. One patient (20%) had inappropriate ICD shock. For LQT3 patients, 4 (80%) patients developed syncope during resting state, and 1 (20%) developed ventricular tachycardia during exercise test. One LQT5 patients experienced syncope and ICD shock under specific triggers (emotional excitement). One LQT11 patient had repeated ICD shocks under specific inducement (fatigue). One LQT7 patient experienced inappropriate ICD shock. Left cardiac sympathetic denervation (LCSD) significantly alleviated the symptoms in 2 children with Jervell-Lange Nielson syndrome (JLNS) post ineffective β-blocker medication. Nadolol succeeded in eliminating cardiac events in one patient with LQT2 post ineffective metoprolol medication. Mexiletine significantly improved symptoms in 2 patients with LQT2 post ineffective β-blocker medication. Conclusions: Medication withdrawal is an important trigger of the recurrence of cardiac events among patients with symptomatic congenital long QT syndrome.
Adolescent ; Adult ; Child ; Child, Preschool ; Death, Sudden, Cardiac ; Electrocardiography ; Female ; Heart ; Humans ; Infant ; Long QT Syndrome ; Retrospective Studies ; Young Adult

Early recognition and treatment for early warning electrocardiogram (ECG) of sudden death are very important to prevent and treat malignant arrhythmia and sudden death. Previous studies have found that R-on-T and T wave alternation, and QT interval prolongation are closely related to malignant arrhythmia or sudden death, which are included in the critical value of ECG.By analyzing the ECG characteristics of 4 patients with sudden death, we found that although the causes of the patients were different, there were transient prolongation of QT interval after premature contraction in 12 lead ECG, followed by malignant arrhythmia or sudden death. Thus, we thought that the transient prolongation of QT interval after premature contraction had a high value for warning malignant arrhythmia or sudden death. This phenomenon should be paid enough attention to reduce the risk of sudden death.
Arrhythmias, Cardiac/diagnosis* ; Death, Sudden ; Death, Sudden, Cardiac ; Electrocardiography ; Humans ; Long QT Syndrome/diagnosis*

K⁺ channels are key components of the primary and secondary basolateral Cl- pump systems, which are important for secretion from the salivary glands. Paroxetine is a selective serotonin reuptake inhibitor (SSRI) for psychiatric disorders that can induce QT prolongation, which may lead to torsades de pointes. We studied the effects of paroxetine on a human K⁺ channel, human ether-a-go-go-related gene (hERG), expressed in Xenopus oocytes and on action potential in guinea pig ventricular myocytes. The hERG encodes the pore-forming subunits of the rapidly-activating delayed rectifier K⁺ channel (I(Kr)) in the heart. Mutations in hERG reduce I(Kr) and cause type 2 long QT syndrome (LQT2), a disorder that predisposes individuals to life-threatening arrhythmias. Paroxetine induced concentration-dependent decreases in the current amplitude at the end of the voltage steps and hERG tail currents. The inhibition was concentration-dependent and time-dependent, but voltage-independent during each voltage pulse. In guinea pig ventricular myocytes held at 36℃, treatment with 0.4 µM paroxetine for 5 min decreased the action potential duration at 90% of repolarization (APD₉₀) by 4.3%. Our results suggest that paroxetine is a blocker of the hERG channels, providing a molecular mechanism for the arrhythmogenic side effects of clinical administration of paroxetine.
Action Potentials ; Animals ; Arrhythmias, Cardiac ; Guinea Pigs ; Heart ; Humans ; Long QT Syndrome ; Muscle Cells ; Oocytes ; Paroxetine ; Salivary Glands ; Serotonin ; Tail ; Torsades de Pointes ; Xenopus

BACKGROUND: There has been a campaign by the National Education on Sleeping Habits and Living Environment, to reduce the incidence of sudden infant death syndrome (SIDS). However, more than 100 infants die suddenly and unexplainably before the age of 1 year in Korea. Long QT syndrome (LQTS), an inheritable cardiac disease, has been reported to likely be associated with up to 14% of SIDS cases. However, genetic studies of the association between SIDS and LQTS have not yet been conducted in Korea. METHODS: We conducted genetic analysis using genomic DNA extracted from paraffin-embedded tissue blocks from 200 SIDS cases autopsied between 2005 and 2013. We analyzed the following genetic mutations associated with LQTS, KCNQ1, SCN5A, KCNE1, KCNE2, KCNJ2, and CAV3. RESULTS: Of the 200 SIDS cases, 58% involved male infants (116 male and 84 female infants, respectively), the mean age was 140 days (median, 107 days; range, 24–270 days), and they were all of Asian-Korean ethnicity. SIDS IA category criteria comprised 45 cases (22.5%) while the rest were SIDS IB. Fifteen infants (7.5%) had R1193Q in SCN5A, of doubtful pathogenicity, and no pathogenic LQTS variants were observed. CONCLUSION: This genetic investigation of LQTS in SIDS showed a low diagnostic yield. These findings suggest that LQTS molecular autopsy could be cautiously conducted in selected cases with family involvement to improve the available genetic counseling information. Meanwhile, a national SIDS registry should be established to document and evaluate the genetic risk of SIDS in Korea.
Autopsy ; DNA ; Education ; Female ; Genetic Counseling ; Heart Diseases ; Humans ; Incidence ; Infant ; Korea* ; Long QT Syndrome* ; Male ; Retrospective Studies* ; Sudden Infant Death* ; Virulence

Long QT syndrome is a cardiac repolarization disorder and is associated with an increased risk of torsades de pointes. The acquired form is most often attributable to administration of specific medications and/or electrolyte imbalance. This review provides insights into the risk for QT prolongation associated with drugs frequently used in the treatment of chronic pain. In the field of pain medicine all the major drug classes (i.e. NSAIDs, opioids, anticonvulsive and antidepressant drugs, cannabinoids, muscle relaxants) contain agents that increase the risk of QT prolongation. Other substances, not used in the treatment of pain, such as proton pump inhibitors, antiemetics, and diuretics are also associated with long QT syndrome. When the possible benefits of therapy outweigh the associated risks, slow dose titration and electrocardiography monitoring are recommended.
Analgesics ; Analgesics, Opioid ; Anti-Inflammatory Agents, Non-Steroidal ; Anticonvulsants ; Antidepressive Agents ; Antiemetics ; Cannabinoids ; Chronic Pain ; Diuretics ; Electrocardiography ; Long QT Syndrome ; Muscle Relaxants, Central ; Narcotics ; Proton Pump Inhibitors ; Torsades de Pointes