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Prolonged QT syndrome

Worawan B Limpitikul, Ivy E Dick, David Tester, Nicole J Boczek, Pattraranee Limphong, Wanjun Yang, Myoung Hyun Choi, Jennifer Babich, Deborah DiSilvestre, Ronald J Kanter, Gordon F Tomaselli, Michael J Ackerman, David Yue
RATIONALE: Calmodulinopathies comprise a new category of potentially life-threatening genetic arrhythmia syndromes capable of producing severe long QT syndrome (LQTS) with mutations involving either CALM1, CALM2, or CALM3 The underlying basis of this form of LQTS is a disruption of Ca(2+)/CaM-dependent inactivation (CDI) of L-type Ca(2+) channels (LTCCs). OBJECTIVE: To gain insight into the mechanistic underpinnings of calmodulinopathies and devise new therapeutic strategies for the treatment of this form of LQTS...
October 20, 2016: Circulation Research
Jie Wu, Wei-Guang Ding, Minoru Horie
Long QT syndrome type 1 (LQT1) is a subtype of a congenital cardiac syndrome caused by mutation in the KCNQ1 gene, which encodes the α-subunit of the slow component of delayed rectifier K(+) current (IKs) channel. Arrhythmias in LQT1 are characterized by prolongation of the QT interval on ECG, as well as the occurrence of life-threatening cardiac events, frequently triggered by adrenergic stimuli (e.g., physical or emotional stress). During the past two decades, much advancement has been made in understanding the molecular pathogenesis underlying LQT1...
October 2016: Journal of Arrhythmia
Altuğ Ösken, Nizamettin Selçuk Yelgeç, Regayip Zehir, Tuğba Kemaloğlu Öz, Selçuk Yaylacı, Ramazan Akdemir, Hüseyin Gündüz
Drug-induced torsades de pointes (TdP) is a rare but potentially fatal adverse effect of commonly prescribed medications including cardiac and noncardiac drugs. Importantly, many drugs have been reported to cause the characteristic Brugada syndrome-linked electrocardiography (ECG) abnormalities and/or (fatal) ventricular tachyarrhythmias. Chlorpheniramine and propranolol have the arrhythmogenic effects reported previously. A review of literature revealed a large number of case reports of chlorpheniramine or propranolol use resulting in QTc prolongation, TdP, or both...
July 2016: Indian Journal of Pharmacology
Shegu Gilbert, Devender Singh, M Lawrance Jesuraj
Severe QT interval prolongation >500ms occurs in one quarter of cardiac surgical patients in the perioperative period while moderate prolongation occurs in most of them. Prolonged QT interval may be associated with torsades de pointes and lead to sudden cardiac death. Because of the high incidence of prolonged QT in cardiac surgery patients and its perioperative adverse outcomes, it is vital to identify it early and take necessary precautions. We report and discuss the catastrophic events and management of two patients with long QT syndrome complicating mitral valve replacement...
September 2016: Indian Heart Journal
Frank F Vincenzi, Philippe Lunetta
While SCUBA diving, a 44-year-old Caucasian patient had an abnormal cardiac rhythm, presumably Torsade de Pointes (TdP), during the initial descent to depth. Upon surfacing, she developed ventricular fibrillation and died. The patient had been treated for mild depression for nearly a year with citalopram 60 mg per day, a drug known to cause prolonged QT interval. She had also been treated with two potentially hepatotoxic drugs. Liver impairment causes selective loss of cytochrome P450 (CYP) 2C19 activity, the major pathway for metabolism of citalopram...
December 2015: Drug Saf Case Rep
Tal Lorberbaum, Kevin J Sampson, Jeremy B Chang, Vivek Iyer, Raymond L Woosley, Robert S Kass, Nicholas P Tatonetti
BACKGROUND: QT interval-prolonging drug-drug interactions (QT-DDIs) may increase the risk of life-threatening arrhythmia. Despite guidelines for testing from regulatory agencies, these interactions are usually discovered after drugs are marketed and may go undiscovered for years. OBJECTIVES: Using a combination of adverse event reports, electronic health records (EHR), and laboratory experiments, the goal of this study was to develop a data-driven pipeline for discovering QT-DDIs...
October 18, 2016: Journal of the American College of Cardiology
Rui Fan, Ruirui Ji, Wenxin Zou, Guoliang Wang, Hu Wang, Daniel James Penney, Jin Jun Luo, Yuxin Fan
Andersen-Tawil syndrome (ATS) is an autosomal dominant, multisystem channelopathy characterized by periodic paralysis, ventricular arrhythmias and distinctive dysmorphic facial or skeletal features. The disorder displays marked intrafamilial variability and incomplete penetrance. Myasthenia gravis (MG) is an autoimmune disorder that demonstrates progressive fatigability, in which the nicotinic acetylcholine receptor (AChR) at neuromuscular junctions is the primary autoantigen. The present study reports a rare case of a 31-year-old woman with a history of morbid obesity and periodic weakness, who presented with hemodynamic instability, cardiogenic shock and facial anomalies...
October 2016: Experimental and Therapeutic Medicine
Nil Ozyuncu, Sevinc Akturk, Turkan Seda Tan Kurklu, Cetin Erol
Pheochromocytoma is a rare adrenal gland tumour, usually alerting the physician by causing hypertensive tachycardic attacks. Patients with pheochromocytoma can rarely present with clinical signs similar to acute coronary syndrome. QT interval prolongation and ST segment changes due to pheochromocytoma have also been reported in the literature in a few case reports. We report a patient who had been admitted to the emergency department with chest pain, ischaemic ECG changes and marked QT prolongation. Despite a normal coronary angiogram, we observed that the QT interval and ST segment morphologies had changed during the hospitalisation period...
2016: BMJ Case Reports
Jukka Kuusela, Jiyeong Kim, Esa Räsänen, Katriina Aalto-Setälä
Healthy human heart rate fluctuates overtime showing long-range fractal correlations. In contrast, various cardiac diseases and normal aging show the breakdown of fractal complexity. Recently, it was shown that human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) intrinsically exhibit fractal behavior as in humans. Here, we investigated the fractal complexity of hiPSC-derived long QT-cardiomyocytes (LQT-CMs). We recorded extracellular field potentials from hiPSC-CMs at baseline and under the effect of various compounds including β-blocker bisoprolol, ML277, a specific and potent IKs current activator, as well as JNJ303, a specific IKs blocker...
September 19, 2016: Stem Cell Reviews
Edelmann J, Dobosz T, Sobieszczanska M, Kawecka-Negrusz M, Dreßler J, Nastainczyk-Wulf M
Congenital long QT-syndrome (LQTS) is an inherited cardiac arrhythmia, which is characterized by a prolonged QT interval which predisposes to sudden cardiac death due to ventricular arrhythmias. The altered functions are based on different mutations in LQTS-associated genes. In this study, we performed a mutation analysis for the detection of 125 LQTS-associated single nucleotide polymorphisms (SNPs) focused on the genes KCNQ1, KCNH2, and SCN5A by using the SNaPshot multiplex minisequencing technique. Furthermore, we investigated 152 autopsy-negative cases from younger adults and infants, as well as samples from patients with clinically suspicion for LQTS, in which we found two types of variations...
September 9, 2016: International Journal of Legal Medicine
Miho Kawaida, Tokiya Abe, Toshio Nakanishi, Yoko Miyahara, Hiroyuki Yamagishi, Michiie Sakamoto, Taketo Yamada
Timothy syndrome (TS) is a congenital long QT syndrome that is associated with syndactyly and mutations in CACNA1C, encoding an L-type voltage-dependent calcium channel, Cav1.2. Recently, TS has been associated with autism and other psychological disorders. This case indicated bradycardia by prenatal screening and was diagnosed as TS by the occurrence of syndactyly and QT prolongation at birth. Despite therapy with anti-arrhythmia reagents and a pacemaker, the patient died 2 months after birth and was autopsied...
October 2016: Pathology International
Arthur A M Wilde, Arthur J Moss, Elizabeth S Kaufman, Wataru Shimizu, Derick R Peterson, Jesaia Benhorin, Coeli Lopes, Jeffrey A Towbin, Carla Spazzolini, Lia Crotti, Wojciech Zareba, Ilan Goldenberg, Jørgen K Kanters, Jennifer L Robinson, Ming Qi, Nynke Hofman, David J Tester, Connie R Bezzina, Marielle Alders, Takeshi Aiba, Shiro Kamakura, Yoshihiro Miyamoto, Mark L Andrews, Scott McNitt, Bronislava Polonsky, Peter J Schwartz, Michael J Ackerman
BACKGROUND: Risk stratification in patients with type 3 long-QT syndrome (LQT3) by clinical and genetic characteristics and effectiveness of β-blocker therapy has not been studied previously in a large LQT3 population. METHODS: The study population included 406 LQT3 patients with 51 sodium channel mutations; 391 patients were known to be event free during the first year of life and were the focus of our study. Clinical, electrocardiographic, and genetic parameters were acquired for patients from 7 participating LQT3 registries...
September 20, 2016: Circulation
Mika Kumakura, Koji Hara, Takeyoshi Sata
Although patients with congenital long QT syndrome (c-LQTS) are considered to be at high risk for anesthesia, few reports describe c-LQTS genotype-specific considerations for anesthesia. We describe a case of torsade de pointes (TdP) caused by sevoflurane in a patient with c-LQTS genotype 2 (LQT2). A 39-year-old woman diagnosed with c-LQTS was scheduled for an elective therapeutic abortion. Immediately after starting the operation, the patient developed TdP. Since pulseless ventricular tachycardia was sustained despite intravenous injection of lidocaine, defibrillation was performed...
September 2016: Journal of Clinical Anesthesia
Ankit Upadhyay, Vijaykumar Bodar, Mohammad Malekzadegan, Sharanjit Singh, William Frumkin, Aditya Mangla, Kaushik Doshi
Loperamide is over-the-counter antidiarrheal agent acting on peripherally located μ opioid receptors. It is gaining popularity among drug abusers as opioid substitute. We report a case of a 46-year-old male that was presented after cardiac arrest. After ruling out ischemia, cardiomyopathy, pulmonary embolism, central nervous system pathology, sepsis, and other drug toxicity, we found out that patient was using around 100 mg of Loperamide to control his chronic diarrhea presumably because of irritable bowel syndrome for last five years and consumed up to 200 mg of Loperamide daily for last two days before the cardiac arrest...
2016: Case Reports in Cardiology
Pei-Chi Yang, Nesrine El-Bizri, Lucia Romero, Wayne R Giles, Sridharan Rajamani, Luiz Belardinelli, Colleen E Clancy
BACKGROUND: The QT interval is a phase of the cardiac cycle that corresponds to action potential duration (APD) including cellular repolarization (T-wave). In both clinical and experimental settings, prolongation of the QT interval of the electrocardiogram (ECG) and related proarrhythmia have been so strongly associated that a prolonged QT interval is largely accepted as surrogate marker for proarrhythmia. Accordingly, drugs that prolong the QT interval are not considered for further preclinical development resulting in removal of many promising drugs from development...
August 18, 2016: Journal of Molecular and Cellular Cardiology
Takashi Nakashima, Tomoki Kubota, Nobuhiro Takasugi, Yuichiro Kitagawa, Takahiro Yoshida, Hiroaki Ushikoshi, Masanori Kawasaki, Kazuhiko Nishigaki, Shinji Ogura, Shinya Minatoguchi
OBJECTIVE: A fatal cardiac complication can occasionally present in malnourished patients during refeeding; this is known as refeeding syndrome. However, to our knowledge, hyperglycemia preceding torsades de pointes with QT prolongation during refeeding has not been reported. In the present study, we present a case in which hyperglycemia preceded torsades de pointes with QT prolongation during refeeding. The aim of this study was to determine the possible mechanism underlying QT prolongation during refeeding and indicate how to prevent it...
June 5, 2016: Nutrition
Nirav Patel, Abhishek Shenoy, George Dous, Haroon Kamran, Nabil El-Sherif
Background. Takotsubo cardiomyopathy (TCM) is sudden and reversible myocardial dysfunction often attributable to physical or emotional triggers. Case Report. We describe a 51-year-old man presented to emergency department with sepsis from urinary tract infection (UTI). He was placed on cefepime for UTI and non-ST-elevation myocardial infarction protocol given elevated troponins with chest pain. Subsequently, patient was pulseless with torsades de pointes (TdP) and then converted to sinus rhythm with cardioversion...
2016: Case Reports in Cardiology
S A Immanuel, A Sadrieh, M Baumert, J P Couderc, W Zareba, A P Hill, J I Vandenberg
Long QT syndrome (LQTS) is an inherited disorder associated with prolongation of the QT/QTc interval on the surface electrocardiogram (ECG) and a markedly increased risk of sudden cardiac death due to cardiac arrhythmias. Up to 25% of genotype-positive LQTS patients have QT/QTc intervals in the normal range. These patients are, however, still at increased risk of life-threatening events compared to their genotype-negative siblings. Previous studies have shown that analysis of T-wave morphology may enhance discrimination between control and LQTS patients...
September 2016: Physiological Measurement
André F Carvalho, Manu S Sharma, André R Brunoni, Eduard Vieta, Giovanni A Fava
Newer generation antidepressant drugs (ADs) are widely used as the first line of treatment for major depressive disorders and are considered to be safer than tricyclic agents. In this critical review, we evaluated the literature on adverse events, tolerability and safety of selective serotonin reuptake inhibitors, serotonin noradrenaline reuptake inhibitors, bupropion, mirtazapine, trazodone, agomelatine, vilazodone, levomilnacipran and vortioxetine. Several side effects are transient and may disappear after a few weeks following treatment initiation, but potentially serious adverse events may persist or ensue later...
2016: Psychotherapy and Psychosomatics
Nihal Bakeer, Jeanne James, Swarnava Roy, Janaka Wansapura, Shiva Kumar Shanmukhappa, John N Lorenz, Hanna Osinska, Kurt Backer, Anne-Cecile Huby, Archana Shrestha, Omar Niss, Robert Fleck, Charles T Quinn, Michael D Taylor, Enkhsaikhan Purevjav, Bruce J Aronow, Jeffrey A Towbin, Punam Malik
Cardiopulmonary complications are the leading cause of mortality in sickle cell anemia (SCA). Elevated tricuspid regurgitant jet velocity, pulmonary hypertension, diastolic, and autonomic dysfunction have all been described, but a unifying pathophysiology and mechanism explaining the poor prognosis and propensity to sudden death has been elusive. Herein, SCA mice underwent a longitudinal comprehensive cardiac analysis, combining state-of-the-art cardiac imaging with electrocardiography, histopathology, and molecular analysis to determine the basis of cardiac dysfunction...
August 30, 2016: Proceedings of the National Academy of Sciences of the United States of America
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