keyword
MENU ▼
Read by QxMD icon Read
search

Torsades

keyword
https://www.readbyqxmd.com/read/29021858/landiolol-suppression-of-electrical-storm-of-torsades-de-pointes-in-patients-with-congenital-long-qt-syndrome-type-2-and-myocardial-ischemia
#1
Ryota Kitajima, Takeshi Aiba, Tsukasa Kamakura, Kohei Ishibashi, Mitsuru Wada, Yuko Inoue, Koji Miyamoto, Hideo Okamura, Takashi Noda, Satoshi Nagase, Yu Kataoka, Yasuhide Asaumi, Teruo Noguchi, Satoshi Yasuda, Kengo Kusano
A 76-year-old man who had been diagnosed with long-QT syndrome type 2 had frequent syncopal attacks. The electrocardiogram was monitored, and frequent torsades de pointes (TdP) was detected despite administration of conventional medications: oral propranolol, verapamil, intravenous magnesium sulfate, verapamil, and lidocaine. In contrast, 2 μg/kg/min landiolol could completely suppress TdP. Subsequently, an implantable cardioverter defibrillator was placed, and he was diagnosed with silent myocardial ischemia using myocardial perfusion scintigraphy and coronary angiography...
October 2017: Journal of Arrhythmia
https://www.readbyqxmd.com/read/29020721/artefact-mimicking-torsades-treat-the-patient-not-the-ecg
#2
Una Bergin, Richard M Lynch
ECG interpretation is an essential skill in the management of the acutely unwell patient and in addition to history taking and physical examination has been shown to have a significant effect on referral patterns to cardiologists. One of the basic initial steps in ECG interpretation is assessment for the presence of artefact which if present can dramatically influence the diagnosis. The most common sources of artefact are tremor e.g. in Parkinson’s disease, loose skin electrodes and electromagnetic interference from other medical devices and mobile phones...
February 2017: Practitioner
https://www.readbyqxmd.com/read/29016765/broad-antiarrhythmic-effect-of-mexiletine-in-different-arrhythmia-models
#3
Gerrit Frommeyer, Jonas Garthmann, Christian Ellermann, Dirk G Dechering, Simon Kochhäuser, Florian Reinke, Julia Köbe, Kristina Wasmer, Lars Eckardt
Aims: Experimental studies and clinical reports suggest antiarrhythmic properties of mexiletine in different arrhythmias. We aimed at investigating mexiletine in experimental models of atrial fibrillation (AF) as well as in long-QT- (LQTS) and short-QT-syndrome (SQTS). Methods and results: In 15 isolated rabbit hearts, erythromycin (300 µM) was infused for simulation of long-QT-2-syndrome. In further 13 hearts, veratridine was administered to simulate long-QT-3-syndrome...
August 1, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29016752/hypothyroidism-and-congenital-long-qt-additive-effect-causing-torsades
#4
Moustafa Elsheshtawy, Felix Yang, Ashok Khanna
No abstract text is available yet for this article.
July 7, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/28964110/a-model-of-cardiac-ryanodine-receptor-gating-predicts-experimental-ca-2-dynamics-and-ca-2-triggered-arrhythmia-in-the-long-qt-syndrome
#5
Dan Wilson, Bard Ermentrout, Jan Němec, Guy Salama
Abnormal Ca(2+) handling is well-established as the trigger of cardiac arrhythmia in catecholaminergic polymorphic ventricular tachycardia and digoxin toxicity, but its role remains controversial in Torsade de Pointes (TdP), the arrhythmia associated with the long QT syndrome (LQTS). Recent experimental results show that early afterdepolarizations (EADs) that initiate TdP are caused by spontaneous (non-voltage-triggered) Ca(2+) release from Ca(2+)-overloaded sarcoplasmic reticulum (SR) rather than the activation of the L-type Ca(2+)-channel window current...
September 2017: Chaos
https://www.readbyqxmd.com/read/28963955/structural-investigation-of-vesnarinone-at-the-pore-domains-of-open-and-open-inactivated-states-of-herg1-k-channel
#6
Gülru Kayık, Nurcan Ş Tüzün, Serdar Durdagi
In this study, the dynamics of vesnarinone bounded hERG1 K(+) channels are investigated using in silico approaches such as molecular docking, molecular dynamics (MD) simulations, MM/PBSA (Molecular Mechanics/Poisson Boltzmann Surface Area) calculations and Principal Component Analysis (PCA). Vesnarinone (a cardiotonic agent) falls into a category of drugs that inhibit phosphodiesterase 3-type (PDE3) enzymes. PDE3 enzymes have specific roles in the dehydyrolysis of intracellular second messengers 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP)...
September 6, 2017: Journal of Molecular Graphics & Modelling
https://www.readbyqxmd.com/read/28959214/adrenergic-stress-protection-of-human-ips-cell-derived-cardiomyocytes-by-fast-kv7-1-recycling
#7
Ilaria Piccini, Edda Fehrmann, Stefan Frank, Frank U Müller, Boris Greber, Guiscard Seebohm
The fight-or-flight response (FFR), a physiological acute stress reaction, involves positive chronotropic and inotropic effects on heart muscle cells mediated through β-adrenoceptor activation. Increased systolic calcium is required to enable stronger heart contractions whereas elevated potassium currents are to limit the duration of the action potentials and prevent arrhythmia. The latter effect is accomplished by an increased functional activity of the Kv7.1 channel encoded by KCNQ1. Current knowledge, however, does not sufficiently explain the full extent of rapid Kv7...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28955244/human-in-silico-drug-trials-demonstrate-higher-accuracy-than-animal-models-in-predicting-clinical-pro-arrhythmic-cardiotoxicity
#8
Elisa Passini, Oliver J Britton, Hua Rong Lu, Jutta Rohrbacher, An N Hermans, David J Gallacher, Robert J H Greig, Alfonso Bueno-Orovio, Blanca Rodriguez
Early prediction of cardiotoxicity is critical for drug development. Current animal models raise ethical and translational questions, and have limited accuracy in clinical risk prediction. Human-based computer models constitute a fast, cheap and potentially effective alternative to experimental assays, also facilitating translation to human. Key challenges include consideration of inter-cellular variability in drug responses and integration of computational and experimental methods in safety pharmacology. Our aim is to evaluate the ability of in silico drug trials in populations of human action potential (AP) models to predict clinical risk of drug-induced arrhythmias based on ion channel information, and to compare simulation results against experimental assays commonly used for drug testing...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28942951/the-algorithmic-performance-of-j-tpeak-for-drug-safety-clinical-trial
#9
Simon C Chien, Richard E Gregg
INTRODUCTION: The interval from J-point to T-wave peak (JTp) in ECG is a new biomarker able to identify drugs that prolong the QT interval but have different ion channel effects. If JTp is not prolonged, the prolonged QT may be associated with multi ion channel block that may have low torsade de pointes risk. From the automatic ECG measurement perspective, accurate and repeatable measurement of JTp involves different challenges than QT. We evaluated algorithm performance and JTp challenges using the Philips DXL diagnostic 12/16/18-lead algorithm...
August 15, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28940299/a-history-of-drug-induced-torsades-de-pointes-is-associated-with-t-wave-morphological-abnormalities
#10
Tanveer A Bhuiyan, Claus Graff, Jørgen K Kanters, Jacob Melgaard, Egon Toft, Stefan Kääb, Johannes J Struijk
The hypothesis of the study is that TdP history can be better identified using T-wave morphology compared to QTcF at baseline. ECGs were recorded at baseline and during sotalol challenge in 20 patients with a history of TdP (+TdP) and 16 patients without previous TdP (-TdP). The Fridericia-corrected QT interval (QTcF) and T-wave morphology combination score (MCS) were calculated. At baseline, there was no significant difference in QTcF between the groups (+TdP: QTcF = 446±9 ms; -TdP: QTcF = 431±9 ms, p = 0...
September 22, 2017: Clinical Pharmacology and Therapeutics
https://www.readbyqxmd.com/read/28928044/electrocardiographic-biomarkers-to-confirm-drug-s-electrophysiological-effects-used-for-proarrhythmic-risk-prediction-under-cipa
#11
Jose Vicente, Meisam Hosseini, Lars Johannesen, David G Strauss
The ECG plays a critical role in the thorough QT study. This clinical study is part of the assessment of proarrhythmic potential of drugs under the current regulatory paradigm. While the current paradigm has been successful in preventing drugs with unexpected QT prolongation or torsade risk from reaching the market, the focus on QT prolongation has likely resulted in potentially beneficial compounds with minimal torsade risk being dropped from development. The Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative is developing and validating a new mechanistic-based paradigm for cardiac safety evaluation of drugs...
August 9, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/28904293/characteristics-of-electromechanical-window-in-anesthetized-rabbit-models-of-short-qt-and-long-qt-syndromes
#12
Vudhiporn Limprasutr, Nakkawee Saengklub, Pradtana Meedech, Anusak Kijtawornrat, Robert L Hamlin
The current regulatory guidelines recommend the use of QT interval to assess the risk of arrhythmogenic potential of new chemical entities. Recently, the electromechanical window (EMW), the difference in duration between electrical and mechanical systole, has been proposed as markers for drug-induced torsades de pointes (TdP); however, data of EMW in short QT model are not available. This study aimed to characterize the EMW as a marker for drug-induced ventricular arrhythmias in anesthetized rabbit model of long QT syndrome type 2 (LQT2) and short QT syndrome (SQTS) infused with reference compounds known to lengthen or shorten QT intervals...
2017: Journal of Toxicological Sciences
https://www.readbyqxmd.com/read/28895028/prevalence-of-qt-interval-prolonging-drug-drug-interactions-qt-ddis-in-psychiatry-wards-of-tertiary-care-hospitals-in-pakistan-a-multicenter-cross-sectional-study
#13
Qasim Khan, Mohammad Ismail, Iqbal Haider, Fahadullah Khan
Background QT prolongation and associated arrhythmias, torsades de pointes (TdP), are considerable negative outcomes of many antipsychotic and antidepressant agents frequently used by psychiatric patients. Objective To identify the prevalence, levels, and predictors of QT prolonging drug-drug interactions (QT-DDIs), and AZCERT (Arizona Center for Education and Research on Therapeutics) classification of drugs involved in QT-DDIs. Setting Psychiatry wards of three major tertiary care hospitals of Khyber-Pakhtunkhwa, Pakistan...
September 12, 2017: International Journal of Clinical Pharmacy
https://www.readbyqxmd.com/read/28878692/optimization-of-an-in-silico-cardiac-cell-model-for-proarrhythmia-risk-assessment
#14
Sara Dutta, Kelly C Chang, Kylie A Beattie, Jiansong Sheng, Phu N Tran, Wendy W Wu, Min Wu, David G Strauss, Thomas Colatsky, Zhihua Li
Drug-induced Torsade-de-Pointes (TdP) has been responsible for the withdrawal of many drugs from the market and is therefore of major concern to global regulatory agencies and the pharmaceutical industry. The Comprehensive in vitro Proarrhythmia Assay (CiPA) was proposed to improve prediction of TdP risk, using in silico models and in vitro multi-channel pharmacology data as integral parts of this initiative. Previously, we reported that combining dynamic interactions between drugs and the rapid delayed rectifier potassium current (IKr) with multi-channel pharmacology is important for TdP risk classification, and we modified the original O'Hara Rudy ventricular cell mathematical model to include a Markov model of IKr to represent dynamic drug-IKr interactions (IKr-dynamic ORd model)...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28862317/is-prolongation-of-corrected-qt-interval-associated-with-seizures-induced-by-electroconvulsive-therapy-reduced-by-atropine-sulfate
#15
Yoko Suzuki, Miho Miyajima, Katsuya Ohta, Noriko Yoshida, Rie Omoya, Mayo Fujiwara, Takafumi Watanabe, Masaki Okumura, Hiroaki Yamazaki, Masayuki Shintaku, Issei Murata, Shigeru Ozaki, Takeshi Sasaki, Mitsuru Nakamura, Hiroshi Suwa, Tetsuo Sasano, Tokuhiro Kawara, Masato Matsuura, Eisuke Matsushima
BACKGROUND: Electrocardiogram abnormalities have been reported during electroconvulsive therapy (ECT). A corrected QT interval (QTc) prolongation indicates delayed ventricular repolarization, which can trigger ventricular arrhythmias such as torsade de pointes (TdP). We examined the QTc changes during generalized tonic-clonic seizures induced by ECT, and the effects of atropine sulfate on these QTc changes. METHODS: We analyzed heart rate, QT interval, and QTc in 32 patients with depression who underwent ECT (25 women, 67...
September 1, 2017: Pacing and Clinical Electrophysiology: PACE
https://www.readbyqxmd.com/read/28858645/simulation-study-of-the-ionic-mechanisms-underlying-torsade-de-pointes-in-a-2d-cardiac-tissue
#16
Ponnuraj Kirthi Priya, M Ramasubba Reddy
BACKGROUND: To understand the ionic mechanism behind the genesis of Torsade de Pointes (TdP) occurring with long QT syndrome 2 (LQTS2) in a remodelled transmural tissue. METHODS: The TP06 model is used to simulate the electrical activity of cells in a 2D transmural ventricular model. LQTS2 is realised by reducing the potassium current (IKr) to 0.5 in each cell. Each cell of the tissue is remodelled by increasing the conductance of calcium current (GCaL). The above two factors make the cells prone to early after depolarizations (EADs) development...
August 24, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28855066/emergency-department-approach-to-qtc-prolongation
#17
REVIEW
Ali Pourmand, Maryann Mazer-Amirshahi, Sonya Chistov, Youssef Sabha, Damir Vukomanovic, Mohammed Almulhim
QTc prolongation has been associated with increased risk of developing ventricular tachydysrhythmias, particularly Torsades de Pointes (TdP). QTc prolongation is influenced by many factors including congenital causes, heart rate, metabolic imbalances, and pharmacotherapy. Several commonly used medications in the emergency department (ED), such as antipsychotics and antiemetics, are known to prolong the QT interval. In addition, ED patients may present with conditions that may predispose them to QTc prolongation, such as drug overdose or hypokalemia, which can further complicate management...
August 24, 2017: American Journal of Emergency Medicine
https://www.readbyqxmd.com/read/28853038/drug-induced-qt-prolongation-and-torsades-de-pointes-an-all-exclusive-relationship-or-time-for-an-amicable-separation
#18
Luc M Hondeghem
QT prolongation was perceived as a major antiarrhythmic mechanism, but soon became a surrogate for torsades de pointes (TdP) instead. Drugs that prolong the QT interval range from having potent torsadogenic activity to no proarrhythmic action and even antiarrhythmic effects. Blockade of hERG channels is the primary cause of TdP, but blockade/activation of other channels can also be torsadogenic. TdP is primarily caused by disturbances of TRIaD, but disturbance of wavelength can also contribute to TdP (where TRIaD is triangulation, reverse use dependence, instability and dispersion, and wavelength equals conduction velocity times effective refractory period)...
August 29, 2017: Drug Safety: An International Journal of Medical Toxicology and Drug Experience
https://www.readbyqxmd.com/read/28845232/solifenacin-linked-qt-interval-prolongation-and-torsades-de-pointes
#19
Jonathan J H Bray, Jules C Hancox
No abstract text is available yet for this article.
July 2017: Therapeutic Advances in Drug Safety
https://www.readbyqxmd.com/read/28844424/analysis-of-proarrhythmic-potential-of-an-atypical-antipsychotic-drug-paliperidone-in-the-halothane-anesthetized-dogs
#20
Koki Chiba, Takeshi Wada, Yuji Nakamura, Xin Cao, Mihoko Hagiwara-Nagasawa, Hiroko Izumi-Nakaseko, Kentaro Ando, Koichiro Tanaka, Atsuhiko T Naito, Atsushi Sugiyama
Fatal cases with the use of atypical antipsychotic drug paliperidone have been reported; however, there was no clinical report describing paliperidone-induced torsade de pointes. In this study we assessed its electropharmacological effects together with its proarrhythmic potential in intravenous doses of 0.03, 0.3 and 3 mg/kg using the halothane-anesthetized dogs (n = 5), which could provide approximately 2, 20 and 200 times higher peak plasma drug concentrations than its therapeutic level, respectively...
August 2017: Journal of Pharmacological Sciences
keyword
keyword
28963
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"