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Cardiac memory is the term used to describe an interesting electrocardiographic phenomenon. Whenever a QRS complex is wide and abnormal, such as during ventricular pacing, the T waves will also be abnormal and will point to the opposite direction of the wide QRS. If the QRS then normalizes, such as after cessation of ventricular pacing, the T waves will normalize as well, but at a later stage. The period of cardiac memory is the phase between the sudden normalization of the QRS and the eventual and gradual return of the T waves to their baseline morphology. Cardiac memory is assumed to be an innocent electrocardiographic curiosity. However, during cardiac memory, reduction of repolarizing potassium currents increases left ventricular repolarization gradients. Therefore, when cardiac memory occurs in patients who already have a prolonged QT interval (for whatever reason), it can lead to a frank long QT syndrome with QT-related ventricular arrhythmias (torsades de pointes). These arrhythmogenic effects of cardiac memory are not generally appreciated and are reviewed here for the first time.

Transcatheter pulmonary valve replacement (TPVR) with the Harmony valve (Medtronic, Inc.) was recently approved to treat postoperative native outflow tract pulmonary regurgitation. While the 22 mm Harmony valve Early Feasibility Study demonstrated ventricular tachycardia (VT) in only 5% of patients, little is known about ventricular arrhythmias after TPVR with the larger 25 mm valve (TPV25).A single center review was performed of patients with TPV25 implant from 2020 to 2021. Demographic, cardiac, procedural, and postimplant cardiac telemetry data were collected and compared between patients who did and did not have peri-implant ventricular arrhythmia.Thirty patients underwent TPV25 at a median age of 30 years. On postimplant telemetry, VT events were documented in 12 patients (40%); 11 nonsustained VT (NSVT) (median 3 episodes per patient and 6 beats per episode, maximum 157 episodes) and 1 sustained VT (3%), with Torsades de Pointes secondary to a short coupled premature ventricular contraction (PVC). VT events were associated with annular valve positioning (p lt; 0.001) and increased postimplant PVC burden (p lt; 0.0001), but there was no association between VT and other demongraphic, historical, or procedural factors. The frequency of NSVT events fell from 3/h from 0 to 12 h postimplant to 0.5/hr from 12 to 24 h (p lt; 0.001).VT occurred commonly (40%) in the first 24 h after TPV25 implant, with self-limited NSVT in 11 of 12 patients and 1 patient with cardiac arrest secondary to Torsades de Pointes. VT only occurred with annular valve positioning. Larger, longer-term studies are needed to determine risk factors for and natural history of post-TPVR VT.

A young man presented to the emergency department with seizures and recurrent episodes of polymorphic ventricular tachycardia (PMVT)/torsades de pointes (TdP) requiring cardioversion and administration of intravenous magnesium. A battery of tests performed to identify a cause for his arrhythmias and seizures were all normal. A revisit of history with family revealed he had consumed over 100 tablets/day of loperamide for the past 1 year. A prolonged QT interval on his ECG raised concerns for long QT syndrome (LQTS) (congenital or acquired). Our patient was suspected to have loperamide-induced cardiotoxicity. TdP is a specific PMVT that occurs with a prolonged QT interval and is usually drug-induced. Less frequently, congenital LQTS may be implicated. With supportive care, including mechanical ventilation, vasopressors and temporary transvenous overdrive pacing, our patient recovered completely. We describe the importance of a systematic and time-sensitive approach to diagnosing critical illness. Loperamide overdose may cause QT prolongation, life-threatening arrhythmias/cardiogenic shock, or cardiac arrest. Seizures/epilepsy may also be a manifestation in young patients. There is a substantial need to revisit the safety of over-the-counter medications and increasing awareness of manifestations of drug overdose.

Chloroquine and azithromycin were developed in combination for the preventive treatment of malaria in pregnancy, and more recently were proposed as coronavirus disease 2019 (COVID-19) treatment options. Billions of doses of chloroquine have been administered worldwide over the past 70 years but concerns regarding cardiotoxicity, notably the risk of torsades de pointes (TdP), remain. This investigation aimed to characterize the pharmacokinetics and electrocardiographic effects of chloroquine and azithromycin observed in a large previously conducted healthy volunteer study. Healthy adult volunteers (n = 119) were randomized into 5 arms: placebo, chloroquine alone (600 mg base), or chloroquine with either 500 mg, 1,000 mg, or 1,500 mg of azithromycin all given daily for 3 days. Chloroquine and azithromycin levels, measured using liquid-chromatography tandem mass spectrometry, and electrocardiograph intervals were recorded at frequent intervals. Time-matched changes in the PR, QRS, and heart rate-corrected JT, and QT intervals were calculated and the relationship with plasma concentrations was evaluated using linear and nonlinear mixed-effects modeling. Chloroquine and azithromycin pharmacokinetics were described satisfactorily by two- and three-compartment distribution models, respectively. No drug–drug interaction between chloroquine and azithromycin was observed. Chloroquine resulted in concentration-dependent prolongation of the PR, QRS, JTc and QTc intervals with a minimal additional effect of azithromycin. QRS widening contributed ~ 28% of the observed QT prolongation. Chloroquine causes significant concentration-dependent delays in both ventricular depolarization and repolarization. Co-administration of azithromycin did not significantly increase these effects. The arrhythmogenic risk of TdP associated with chloroquine may have been substantially overestimated in studies which did not separate electrocardiograph QRS and JT prolongation.

We report a 28-year-old female patient with congenital type 2 long QT syndrome (LQTS) in which mexiletine shortened corrected QT interval (QTc) and effectively prevented refractory Torsade de Pointes (TdP) and ventricular fibrillation (VF). She developed TdP and VF, and was subsequently diagnosed with congenital type 2 LQTS. She had refractory TdP and VF every day despite medical therapy including β-blocker. They were completely suppressed after the initiation of mexiletine with shorting of QTc interval.

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been widely used in the Comprehensive in vitro Proarrhythmia Assay (CiPA). The notable difference of the electrophysiological (EP) responses of hiPSC-CMs in serum and serum-free media (SFM) is puzzling and may impact regulatory decision-making on the cardiac safety of candidate drugs in inducing QT prolongation and torsade de pointes (TdP). In this study, we compared the EP responses of hiPSC-CMs to 10 CiPA compounds and moxifloxacin in serum and SFM; explained the potential reason behind the different EP responses—abiotic compound loss to plastic tubes/plates of hydrophobic compounds prepared in SFM; and investigated the impact of compound preparation methods on drug bioavailability in exposure media, which affects the TdP risk prediction of drugs tested in serum-containing and SFM. For assays to be conducted in SFM, awareness of abiotic compound loss of hydrophobic compounds in serum-free preparations is critical for delay repolarization evaluation and data extrapolation from in vitro to in vivo.

Droperidol is a butyrophenone that has recently been reintroduced after a United States Food and Drug Administration (US FDA) black box warning in 2001. Evidence demonstrates utility in a variety of clinical conditions.This paper provides evidence-based updates concerning the use of droperidol for the emergency clinician.Droperidol received a black box warning by the US FDA in 2001 due to concerns for QT prolongation and torsades de pointes; however, reevaluation of the available data suggests droperidol is a safe and efficacious medication. It can be used in the emergency department (ED) setting for many conditions, including acute agitation, headaches, vertigo, nausea, and vomiting. Extensive literature supports that the QT-prolonging effects are transient and that the risk of torsades de pointes is rare with doses utilized in the ED. An electrocardiogram does not need to be routinely obtained before droperidol use but should be considered in patients at high risk for QT prolongation.Current evidence suggests that droperidol is a safe and effective medication for treating nausea and vomiting, headache, vertigo, and agitation in the ED setting.

Drug-induced prolongation of the QT interval is common in a variety of pharmaceutical treatments and can lead to serious clinical outcomes. Although substantial efforts have been made to prevent drug-induced QT interval prolongation, the lack of a centralized data source remains the main obstacle to further study of the underlying mechanism and the development of effective prediction strategies. To fill this gap, we propose a schema for stratifying the risk of marketed QT prolonging drugs based on US Food and Drug Administration (FDA)-approved drug labeling and developed a Drug-Induced QT Prolongation Atlas (DIQTA). Potential application of DIQTA was shown by precision dosing in off-label use and therapeutic strategy optimization, as well as the facilitation of artificial intelligence (AI)-based modeling in predictive toxicity.

The primary objective of this retrospective safety study was to determine the incidence of torsades de pointes (TdP) or death following perioperative administration of low-dose, 4 mg, ondansetron for postoperative nausea and vomiting.This is a single-center retrospective clinical trial.The authors identified 32,737 patients who received 37,589 doses of ondansetron during a 2-year time frame between March 2009 and February 2011 for surgical nausea prophylaxis or treatment of nausea.Patients were cross-matched with an electrocardiogram and adverse outcome database; this identified 4759 patients with documentation of a QTc450 milliseconds (ms), all ventricular tachycardias including TdP within 48 hours of receiving ondansetron, or death within 7 days of receiving ondansetron. No patients developed TdP or died as a direct result of ondansetron administration (n = 0; event rate = 0.0 per 10,000, 95% CI 0.0 to 1.1 per 10,000). Forty-six of 32,737 surgical patients had documented monomorphic ventricular tachycardia (VT) (n = 14; event rate = 4.3 per 10,000, 95% CI 2.3 to 7.2 per 10,000) or died (n = 32; event rate = 9.8 per 10,000, 95% CI 6.7 to 13.8 per 10,000) within 48 h of ondansetron administration. All monomorphic VT episodes were precipitated by existing cardiovascular disease; and 7 of 14 patients had documented monomorphic VT prior to receiving ondansetron. Of the 32 surgical patients who died, all deaths were precipitated by pre-existing disease.No episodes of TdP were identified in patients receiving ondansetron perioperatively. This suggests that low-dose ondansetron does not contribute to the development of TdP.

Purpose Many drugs are associated with the risk of QT prolongation and torsades de pointes (TdP), and different risk assessment tools (RATs) are developed to help clinicians to manage related risk. The aim of this systematic review was to summarize the evidence of different RATs for QT prolonging pharmacotherapy. Methods A systematic review was conducted using PubMed and Scopus databases. Studies concerning risk assessment tools for QT prolonging pharmacotherapy, including older adults, were included. Screening and selection of the studies, data extraction, and risk of bias assessment were undertaken. Results A total of 21 studies were included, involving different risk assessment tools. Most commonly used tools were risk scores (n = 9), computerized physician order entry systems (n = 3), and clinical decision support systems (n = 6). The tools were developed mainly for physicians and pharmacists. Risk scores included a high number of risk factors, both pharmacological and non-pharmacological, for QT prolongation and TdP. The inclusion of patients’ risk factors in computerized physician order entry and clinical decision support systems varied. Conclusion Most of the risk assessment tools for QT prolonging pharmacotherapy give a comprehensive overview of patient-specific risks of QT prolongation and TdP and reduce modifiable risk factors and actual events. The risk assessment tools could be better adapted to different health information systems to help in clinical decision-making. Further studies on clinical validation of risk assessment tools with randomized controlled trials are needed.

Background: QTc prolongation is common in dangerous clinical conditions, associated with an increased risk of life-threatening arrhythmia torsades de pointes. The goal of this short communication is to evaluate the principal causes of risk of QTc prolongation that are observed in an emergency department and discuss the differences between drug- and non-drug-associated factors. Methods: The retrospective analysis was carried out on 130 patients that presented a QTc prolongation (>480 ms for man and >470 for female, respectively), admitted to the emergency department of a single Italian hospital. Patients with pace-maker (22) were excluded from this study. For each patient, a minimum of 3 ECGs (12 leads) were recorded. Attention was paid on electrolytes disturbances and to the pharmacotherapy, with a particular emphasis to the use of antibiotics. Results: Mean age of the patients was 79.6 years (SD=11.3) and females and males were almost equally present (46.6% F, 53.7% M). The average QTc value was 492.2 ms (493.3 ms F, 492.8 M). The patients were divided in those with electrolytes disturbances (24.0%), antimicrobial therapy (35.2%), both antimicrobial therapy and electrolytes disturbances (24.1%), and other causes of QTc prolongation (16.7%). Conclusion: This analysis shows the relevance of the empirical therapy established at the admission, in particular for infective diseases, as an important risk factor for the prolongation of QTc. Other factors that can increase the risk are electrolytes alterations, advanced age, cardiovascular diseases, and drug-drug interaction.

The exact medical complications, leading to the well-known high risk of death in patients with anorexia nervosa (AN), remain elusive. Such deaths are often abrupt with no satisfactory explanation. Suspected causes include cardiac QTc prolongation and, in turn, torsade de pointes (TdP). Psychotropic medications often prescribed to these patients are linked to QTc prolongation. AN is also presumed to cause heart failure due to malnutrition with increased susceptibility to QTc prolongation, and TdP, resulting in sudden cardiac death. Recent literature, however, is conflicting, and the likely cause of death may involve other cardiac abnormalities, such as low heart rate, abnormal heart rate variability, or increased QT dispersion. With an ongoing gap in research explaining the high mortality rate in AN, a compelling need to define the exact proximate causes of death in these patients remains. Because low serum potassium is the most common trigger for TdP, we postulate the early signal of sudden cardiac death, especially in patients with AN who purge, is hypokalemia. We also speculate that hypoglycemia could be a major factor in the sudden death of patients with AN as well as bradycardia or sinus arrest. A path forward to elucidate potential causes is offered.

Background Type 3 long QT syndrome (LQT3) is caused by pathogenic, gain-of-function variants in SCN5A leading to a prolonged action potential, ventricular ectopy, and torsades de pointes. Treatment options include pharmacotherapy, cardiac denervation, and/or device therapy. Rarely, patients with malignant LQT3 require cardiac transplantation. Objective The purpose of this study was to evaluate the role of chronic continuous intravenous (IV) lidocaine as a therapeutic option for select patients with LQT3 refractory to standard therapy. Methods We performed a retrospective review of patients evaluated and treated at Mayo Clinic and identified 4 of 161 patients with LQT3 (2.5%) who were refractory to standard therapies and therefore treated with IV lidocaine. Results There were 4 patients (2 female [50%]). The median age at first IV lidocaine infusion was 2 months (interquartile range 1.5–4.8 months), and the median cumulative duration on IV lidocaine was 11.5 months (interquartile range 8.7–17.8 months). The main indication for IV lidocaine in all patients was persistent ventricular arrhythmias. Before IV lidocaine, all patients received an implantable cardioverter-defibrillator, and while on intermittent IV lidocaine, all patients underwent bilateral cardiac sympathetic denervation. Additionally, 2 (50%) patients had cardiac ablation for premature ventricular complexes. In all patients, lidocaine infusion resulted in a significant reduction of LQT3-triggered cardiac events. The main side effects of IV lidocaine observed were dizziness (n = 2, 50%) and seizures (n = 2, 50%). During follow-up, 3 of 4 (75%) patients underwent orthotopic cardiac transplantation. The remaining patient continues to receive IV lidocaine bolus for rescue as needed. Conclusion For patients with LQT3 who are refractory to standard treatment, chronic IV lidocaine infusion can be used as a potential “bridge to transplant.”

Perioperative Torsade de Pointes (TdP) is a potentially fatal arrhythmia. The association between the prolongation of corrected QT (QTc) interval and TdP has been well described, but prolonged QTc interval is likely not to be a sole determinant. The transmural dispersion of repolarization (TDR) represents regional heterogeneities in repolarization. Prolonged TDR is also considered responsible for TdP. Here we reviewed the current knowledge of perioperative TdP and their known mechanism along with risk factors including drugs. A number of perioperative drugs were reviewed for their effect on QT prolongation and TDR.

We report the death of a 22-year-old woman, with a 3½ year history of cyclic vomiting and cannabis use since age 14, who developed torsades de pointes cardiac arrythmia while being treated in the emergency room for nausea and vomiting. Resuscitation restored spontaneous cardiac circulation, however, due to post-cardiac arrest anoxic brain injury, she never regained consciousness and was declared brain dead 4 days later. Postmortem examination confirmed hypoxic-ischemic encephalopathy, in keeping with the in-hospital diagnosis of brain death. The heart was anatomically normal but showed signs of acute post-cardiopulmonary arrest reperfusion injury. As a consequence of limited survival in hospital in a neuro-vegetative state, early bronchopneumonia and isolated pulmonary thromboemboli were seen. Toxicological studies confirmed cannabis use, in addition to the presence of haloperidol and ondansetron. Genetic studies were performed to rule out a possible channelopathy and revealed a mutation in the MYBPC3 and RYR2 genes. Death in this woman with cannabinoid hyperemesis syndrome was attributed to a fatal cardiac arrhythmia complicating vomiting-induced hypokalemia and treatment with QT interval prolonging and potentially arrhythmogenic medications, with the identified cardiac genetic mutations listed as contributing factors. The emphasis of this report is a) to raise awareness that death can occur due to cyclic vomiting, b) provide a brief but practical overview of cannabinoid hyperemesis syndrome, c) describe the findings from our postmortem examination and come to the most reasonable cause and mechanism of death, d) comment on the risk factors associated with torsades de pointes cardiac arrythmia, and e) conclude that a complete postmortem examination is needed to exclude an anatomical or toxicological cause of death in cannabinoid hyperemesis syndrome, a disabling but preventable disorder.

Background Loperamide, commonly sold under the brand name Imodium® (Johnson & Johnson, Fort Washington, PA), is a widely available, over-the-counter antidiarrheal medication that possesses µ-opioid agonist properties and can have catastrophic cardiac events when misused or abused. Since the start of the opioid epidemic in the United States, there has been an increasing number of case reports and deaths linking loperamide abuse with cardiac events such as torsades de pointes (TdP) and Brugada syndrome. Case Report This case report presents a 22-year-old man who presented in cardiac arrest from polymorphic ventricular tachycardia consistent with TdP and a Type 1 Brugada pattern after intentional loperamide abuse. We discuss this patient's management and the proposed pathophysiology of these two cardiotoxicities, of which, to our knowledge, no previously published case report has displayed both in the same patient after a supratherapeutic loperamide ingestion. Why Should an Emergency Physician Be Aware of This? As the prevalence of opioid dependency and misuse has increased, so, too, has the misuse of un-scheduled medications such as loperamide to achieve central nervous system opioid effects. It is important for the emergency physician to know about and understand loperamide-associated cardiotoxicities such as prolongation of the QRS, unmasking of Brugada patterns, QT prolongation, or ventricular dysrhythmias such as TdP to be able to recognize and treat it.

Summary Background Patients with type 2 diabetes mellitus (T2DM) have a prolonged QT interval and are at high risk of sudden cardiac death. A prolonged QT interval, indicative of impaired ventricular repolarization, is a risk factor for lethal ventricular arrhythmias, such as torsades-de-pointes (TdP). Aims To identify key clinical and biochemical covariates associated with Fridericia's corrected QT interval (QTcF) among euthyroid patients with T2DM, and to describe the temporal relationship between these factors and QTcF. Methods We performed prospective, clinical, biochemical and electrocardiographic measurements among patients with T2DM enrolled in the DIACART study at Pitie-Salpetriere Hospital, at T1 (baseline) and T2 (follow-up), with a median interval of 2.55 years. Results Mean age (63.9 ± 8.5 years), sex (22.35% women), drugs with known risk of TdP according to the CredibleMeds website (Cred-drugsTdP) and serum thyroid-stimulating hormone (TSH) concentrations correlated with QTcF in univariate analysis at both T1 and T2. In multivariable analysis, all these covariates except age were significantly associated with QTcF at both T1 (women: standardized β = 0.24 ± 0.07, P = 0.001; Cred-drugsTdP: β = 0.19 ± 0.07, P = 0.007; TSH concentration: β = 0.18 ± 0.07, P = 0.01) and T2 (women: β = 0.25 ± 0.08, P = 0.002; Cred-drugsTdP: β = 0.25 ± 0.08, P = 0.001; TSH concentration: β = 0.19 ± 0.08, P = 0.01). Furthermore, variation in QTcF over the years was associated with variation in TSH concentration (r = 0.24, P = 0.007) and changes in use of Cred-drugsTdP (r = 0.2, P = 0.02). Conclusions Serum TSH concentration and its variation were associated with QTcF and its variation, even after correcting for the main determinants of QTcF. Interventional optimization of TSH concentration in T2DM warrants further investigation to establish its impact on the risk of TdP and sudden cardiac death.

Editor's note: This is the next installment in a series on electrocardiogram (ECG) interpretation. Nurses in all settings should know the basics, as medications and physiological changes can cause cardiac arrhythmias. Each article will start with a brief case scenario and an ECG strip and then take you step by step through analyzing the heart rhythm.

Long QT syndrome with Torsades de Pointes (TdP) is a life-threatening polymorphic ventricular arrhythmia. The corrected QT (QTc) prolongation >500 milliseconds (ms) has been associated with TdP. Hypocalcaemia due to severe vitamin D deficiency is an uncommon cause of acquired long QT. We hereby present a case of a 40-year-old woman with sensorineural deafness and having symptoms of palpitations and presyncope. She had a QTc interval of 556 ms (reference range, QTc 451–470 ms in adult healthy woman) on 24-hour Holter analysis. Genetic analysis for congenital long QT syndrome was negative. She was diagnosed with severe hypocalcaemia secondary to severe vitamin D deficiency. After treatment with intravenous calcium gluconate, followed by oral vitamin D and calcium supplementation, the QTc became normalised and no further episode of palpitations or presyncope occurred. The causes of vitamin D deficiency was due to inadequate exposure to sunlight and a strict vegan diet.

Sex differences exist in the structure and function of human heart. The patterns of ventricular repolarization in normal electrocardiograms (ECG) differ in men and women: men ECG pattern displays higher T-wave amplitude and increased ST angle. Generally, women have longer QT duration because of reduced repolarization reserve, and thus, women are more susceptible for the occurrence of torsades de pointes associated with drugs prolonging ventricular repolarization. Sex differences are also observed in the prevalence, penetrance and symptom severity, and also in the prognosis of cardiovascular disease. Generally, women live longer, have less clinical symptoms of cardiac diseases, and later onset of symptoms than men. Sex hormones also play an important role in regulating ventricular repolarization, suggesting that hormones directly influence various cellular functions and adrenergic regulation. From the clinical perspective, sex-based differences in heart physiology are widely recognized, but in daily practice, cardiac diseases are often underdiagnosed and untreated in the women. The underlying mechanisms of sex differences are, however, poorly understood. Here, we summarize sex-dependent differences in normal cardiac physiology, role of sex hormones, and differences in drug responses. Furthermore, we also discuss the importance of human induced pluripotent stem cell-derived cardiomyocytes in further understanding the mechanism of differences in women and men.

Approximately 30% to 70% of patients with cirrhosis have QT interval prolongation. In patients without cirrhosis, QT prolongation is associated with an increased risk of ventricular arrhythmias, such as torsade de pointes (TdP). In cirrhotic patients, there is likely a significant association between the corrected QT (QTc) interval and the severity of liver disease, and possibly with increased mortality. We present a stepwise overview of the pathophysiology and management of acquired long QT syndrome in cirrhosis. The QT interval is mainly determined by ventricular repolarization. To compare the QT interval in time it should be corrected for heart rate (QTc), preferably by the Fridericia method. A QTc interval >450 ms in males and >470 ms in females is considered prolonged. The pathophysiological mechanism remains incompletely understood, but may include metabolic, autonomic or hormonal imbalances, cirrhotic heart failure and/or genetic predisposition. Additional external risk factors for QTc prolongation include medication (IKr blockade and altered cytochrome P450 activity), bradycardia, electrolyte abnormalities, underlying cardiomyopathy and acute illness. In patients with cirrhosis, multiple hits and cardiac-hepatic interactions are often required to sufficiently erode the repolarization reserve before long QT syndrome and TdP can occur. While some risk factors are unavoidable, overall risk can be mitigated by electrocardiogram monitoring and avoiding drug interactions and electrolyte and acidbase disturbances. In cirrhotic patients with prolonged QTc interval, a joint effort by cardiologists and hepatologists may be useful and significantly improve the clinical course and outcome. ispartof: GUT AND LIVER vol:16 issue:6 pages:849-860 ispartof: location:Korea (South) status: published

Evaluation of the efficacy and safety of the modified refralon administration protocol for the relief of paroxysmal atrial fibrillation (AF).The study included 39 patients (19 men, mean age 6312.8 years). All patients, after excluding contraindications in the intensive care unit, were injected intravenously with refralon at an initial dose of 5 mg/kg. If AF was preserved and there were no contraindications, after 15 min, repeated administration was performed at a dose of 5 mg/kg (total dose of 10 mg/kg). After another 15 min, while maintaining AF and the absence of contraindications, the third injection of the drug was performed at a dose of 10 mg/kg (total dose of 20 mg/kg). In the absence of relief and the absence of contraindications, another injection of refralon at a dose of 10 mg/kg was performed after another 15 min (in this case, the maximum total dose of 30 mg/kg was reached). After each injected bolus and before the introduction of the next one, the ECG parameters and the general condition of the patient were assessed. The patient was monitored for 24 hours to exclude the arrhythmogenic effect and other possible adverse events.Restoration of sinus rhythm (SR) was noted in 37 patients out of 39 (95%). Of these, 19 people (48.7%) had SR recovery after the administration of a minimum dose of refralone of 5 mg/kg. The effectiveness of the total dose of 10 mg/kg was 76.9%, the dose of 20 mg/kg was 89.7%, and the dose of 30 mg/kg was 95%. Only two patients did not recover HR after administration of the maximum dose of refralon 30 mg/kg. Pathological prolongation of the QTc interval (500 ms) was recorded in 5% of patients. Not a single case of ventricular arrhythmogenic action (induction of Torsade de pointes) has been reported. Bradyarrhythmias (pauses, bradycardia) were registered in 13% of cases, were of a transient nature.Refralon has a high efficiency of relief (95%) of paroxysmal AF, while in almost half of cases (48.7%), SR recovery is achieved using the minimum dose of refralon 5 mg/kg. Despite the prolongation of the QTc500 ms recorded in 5% of cases, none of the patients developed Torsade de pointes after administration of the drug.Цель. Оценка эффективности и безопасности применения модифицированного протокола введения Рефралона для купирования пароксизмальной формы фибрилляции предсердий (ФП). Материалы и методы. В исследование включены 39 больных (из них 19 мужчин, средний возраст 6312,8 года). Всем пациентам после исключения противопоказаний в условиях блока интенсивной терапии вводился внутривенно Рефралон в первоначальной дозе 5 мкг/кг. При сохранении ФП и отсутствии противопоказаний через 15 мин производили повторное введение в дозе 5 мкг/кг (суммарная доза 10 мкг/кг). Еще через 15 мин при сохранении ФП и отсутствии противопоказаний производили третье введение препарата в дозе 10 мкг/кг (суммарная доза 20 мкг/кг). При отсутствии купирования и противопоказаний еще через 15 мин производили еще одно введение Рефралона в дозе 10 мкг/кг (в этом случае достигалась максимальная суммарная доза 30 мкг/кг). После каждого введенного болюса и перед введением последующего проводилась оценка параметров электрокардиограммы и общего состояния пациента. Наблюдение за пациентом продолжалось в течение 24 ч для исключения аритмогенного эффекта и других возможных нежелательных явлений. Результаты. У 37 (95%) из 39 пациентов отмечено восстановление синусового ритма (СР). Из них у 19 (48,7%) человек восстановление СР произошло после введения минимальной дозы Рефралона 5 мкг/кг. Эффективность суммарной дозы 10 мкг/кг составила 76,9%, дозы 20 мкг/кг 89,7%, дозы 30 мкг/кг 95%. Лишь у 2 пациентов восстановления СР после введения максимальной дозы Рефралона 30 мкг/кг не произошло. Патологическое удлинение интервала QTc (500 мс) регистрировалось у 5% больных. Не зарегистрировано ни одного случая желудочкового аритмогенного действия (индукции Torsade de pointes). Брадиаритмии (паузы, брадикардия) зарегистрированы в 13% случаев и носили преходящий характер. Заключение. Рефралон обладает высокой эффективностью (95%) купирования пароксизмальной формы ФП, при этом почти в 1/2 (48,7%) случаев восстановление СР достигается при использовании минимальной дозы Рефралона 5 мкг/кг. Несмотря на зарегистрированное в 5% случаев удлинение интервала QTc (500 мс), ни у одного из больных после введения препарата не отмечалось развития Torsade de pointes.

Drug isomers may differ in their proarrhythmia risk. An interesting example is the drug sotalol, an antiarrhythmic drug comprising d- and l- enantiomers that both block the hERG cardiac potassium channel and confer differing degrees of proarrhythmic risk. We developed a multi-scale in silico pipeline focusing on hERG channel - drug interactions and used it to probe and predict the mechanisms of pro-arrhythmia risks of the two enantiomers of sotalol. Molecular dynamics (MD) simulations predicted comparable hERG channel binding affinities for d- and l-sotalol, which were validated with electrophysiology experiments. MD derived thermodynamic and kinetic parameters were used to build multi-scale functional computational models of cardiac electrophysiology at the cell and tissue scales. Functional models were used to predict inactivated state binding affinities to recapitulate electrocardiogram (ECG) QT interval prolongation observed in clinical data. Our study demonstrates how modeling and simulation can be applied to predict drug effects from the atom to the rhythm for dl-sotalol and also increased proarrhythmia proclivity of d- vs. l-sotalol when accounting for stereospecific beta-adrenergic receptor blocking.

Background Epileptic seizures can be difficult to distinguish from other etiologies that cause cerebral hypoxia, especially cardiac diseases. Long QT syndrome (LQTS), especially LQTS type 2 (LQT2), frequently masquerades as seizures because of the transient cerebral hypoxia caused by ventricular arrhythmia. The high rate of sudden death in LQTS highlights the importance of accurate and early diagnosis; correct diagnosis of LQTS also prevents inappropriate treatment with anti-epileptic drugs (AEDs). Case presentation We report a case of congenital LQT2 with potassium voltage-gated channel subfamily H member 2 gene (KCNH2) mutation misdiagnosed as refractory epilepsy and treated with various AEDs for 22 years. The possibility of cardiac arrhythmia was suspected after the patient presented to the emergency room and the electrocardiograph (ECG) monitor showed paroxysmal ventricular tachycardia during attacks. Atypical seizure like attacks with prodromal uncomfortable chest sensation and palpitation, triggered by auditory stimulation, and typical ventricular tachycardia monitored by ECG raised suspicion for LQT2, which was confirmed by exome sequencing and epileptic seizure was ruled out by 24-h EEG monitoring. Although the patient rejected implantation of an implantable cardioverter defibrillator, β blocker was given and the syncope only attacked 1–2 per year when there was an incentive during the 5 years follow up. Conclusions Our case illustrates how long LQTS can masquerade convincingly as epilepsy and can be treated wrongly with AEDs, putting the patient at high risk of sudden cardiac death. Careful ECG evaluation is recommend for both patients with first seizure and those with refractory epilepsy.

Methadone, a widely-prescribed medication for chronic pain and opioid addiction, is associated with respiratory depression and increased predisposition for torsades de pointes, a potentially fatal arrhythmia. Most methadone-related deaths occur during sleep. The objective of this study was to determine whether methadone’s arrhythmogenic effects increase during sleep, with a focus on cardiac repolarization instability using QT variability index (QTVI), a measure shown to predict arrhythmias and mortality. Sleep study data of 24 patients on chronic methadone therapy referred to a tertiary clinic for overnight polysomnography were compared with two matched groups not on methadone: 24 patients referred for overnight polysomnography to the same clinic (Clinic group), and 24 volunteers who had overnight polysomnography at home (Community group). Despite similar values for heart rate, heart rate variability, corrected QT interval, QTVI and oxygen saturation (SpO(2)) when awake, patients on methadone had larger QTVI (p=0.015 vs Clinic, p1000 premature beats per median sleep period), a precursor for torsades de pointes, was uncommon but more frequent in patients on methadone (p=0.039). This study demonstrates that chronic methadone use is associated with increased cardiac repolarization instability. Methadone’s pro-arrhythmic impact may be mediated by sleep-related hypoxemia which could explain the increased nocturnal mortality associated with this opioid.

The management of atrial fibrillation (AF) in the outpatient setting has become more complex with the utilization of antiarrhythmic drugs (AADs) and increasing complexity of comorbid conditions. The primary care clinician is critically involved in the pharmacologic management of AF, whether it be direct prescription of AADs or managing potential drug-drug interactions with other medications. In this review, we provide instructive, high-yield clinical scenarios and quick clinical references to increase familiarity and comfort with the use of AADs.

Background Antiarrhythmic drugs are often used in the management of patients with atrial fibrillation (AF). Sotalol is conventionally initiated in the inpatient setting for monitoring efficacy and adverse effects, including QTc interval prolongation and torsades de pointes (TdP) proarrhythmia. Objective We aimed to evaluate the efficacy and safety of outpatient initiation of sotalol for the treatment of AF in a select group of patients with cardiac implantable electronic devices (CIEDs): permanent pacemakers (PPMs), implantable cardioverter defibrillators (ICDs), and implantable loop recorders (ILRs) capable of continuous rhythm monitoring remotely. Methods We conducted our clinical study in a real-world practice setting with longitudinal follow-up of the study cohort. We included adult patients with symptomatic paroxysmal and persistent AF eligible for sotalol for rhythm control strategy and who had CIEDs in our study. Patients with a known contraindication to sotalol were excluded. After making a shared management decision with patients, sotalol was initiated as an outpatient, with regular clinical encounters with patients to assess the efficacy and safety of treatment, and monitoring cardiac rhythm and QTc intervals with CIEDs utilizing their remote monitoring platforms. Results The study cohort comprised 105 patients; 38 (36%) females, mean age ± standard deviation (SD) 73.9 ± 10.36 years, and with a CHA2DS2-VASc score of 3.26 ± 1.37 and left ventricular ejection fraction of 60.16 ± 9.10%. Twenty-six (24.8%) patients were implanted with PPMs, 10 (9.5%) with dual-chamber ICDs, and 69 (65.7%) with ILRs. Over a follow-up period of 23 ± 15 months, sotalol was continued at a steady median dose of 80 mg twice daily, 105 ± 42 mg (mean ± SD) in 77 (73%) patients who maintained sinus rhythm, and discontinued in 28 (27%) patients because of inefficacy or development of adverse effects. No adverse effects relating to QTc prolongation and TdP or mortality were observed during the study period. Conclusions Effective and safe outpatient initiation and maintenance of sotalol therapy is possible in select patients who have CIEDs for continuous remote monitoring and surveillance capabilities.

A 2001 U.S. Government Accountability Office (GAO) report indicated 8 of 10 drugs withdrawn from the U.S. market between 1997 and 2000 posed greater risk to women than men. We examined drugs withdrawn from the market for safety-related reasons from January 1, 2001, to January 1, 2018. To be included, drugs must be listed as discontinued on Drugs@FDA and either listed in the Federal Register or cited in literature as being withdrawn for safety-related reasons. Biologics, over-the-counter products, and medical devices were excluded. During the 17-year time span, 19 drugs were withdrawn from the market for safety-related reasons, fewer drugs per year compared to the 3-year period examined in the GAO report. Food and Drug Administration (FDA) has not recommended the market removal of any drug approved since 2005 due to the time from the start of the Q wave to the end of the T wave (QT) interval prolongation resulting in torsades de pointes (TdP) or other abnormal heart rhythms. Furthermore, no drugs approved after the implementation of FDA's 2009 guidance on drug-induced liver injury (DILI) have been withdrawn because of hepatoxicity. All, but one of the drugs discontinued from the market for safety-related reasons during the period examined were approved between 1957 and 2002. TdP and DILI are two relevant examples of drug-induced adverse events posing greater risk to women than men. FDA has made measurable progress incorporating consideration of sex and gender differences into drug trial development and FDA review of these data, supporting inclusion of women in clinical trials, providing a comprehensive drug safety review, and advancing postmarket surveillance and risk assessment, thus strengthening FDA's ability to protect public health.

Drug-induced long QT syndrome can be a very dangerous side effect of existing and developmental drugs. In this work, a model proposed two decades ago addressing the ion specificity of potassium channels is extended to the human ether-à-gogo gene (hERG). hERG encodes the protein that assembles into the potassium channel responsible for the delayed rectifier current in ventricular cardiac myocytes that is often targeted by drugs associated with QT prolongation. The predictive value of this model can guide a rational drug design decision early in the drug development process and enhance NCE (New Chemical Entity) retention. Small molecule drugs containing a nitrogen that can be protonated to afford a formal +1 charge can interact with hERG to prevent the repolarization of outward rectifier currents. Low-level ab initio calculations are employed to generate electronic features of the drug molecules that are known to interact with hERG. These calculations were employed to generate structure–activity relationships (SAR) that predict whether a small molecule drug containing a protonated nitrogen has the potential to interact with and inhibit the activity of the hERG potassium channels of the heart. The model of the mechanism underlying the ion specificity of potassium channels offers predictive value toward optimizing drug design and, therefore, minimizes the effort and expense invested in compounds with the potential for life-threatening inhibitory activity of the hERG potassium channel.

Torsade de pointes (TdP)/QT prolongation is a fatal adverse event (AE) when using antifungal triazoles. We aimed to compare the AE signals of TdP/QT prolongation and onset time among different drugs of this kind comprehensively.This retrospective research was to analyze the U.S. FDA Adverse Event Reporting System (FAERS) database containing 71 quarters of reports through online retrieval. We calculated the strength of signals of TdP/QT prolongation related to 4 drugs of triazoles by using the following indicators: reporting odds ratio (ROR), proportional reporting ratio (PRR), information component (IC), and empirical Bayesian geometric mean (EBGM). The onset time to the AE of TdP/QT prolongation among different antifungal triazoles were compared by using nonparametric tests. Management and visualization of the data were performed by employing MySQL Workbench and R software. The data information including clinical features, AE onset time, and outcomes were extracted for analysis as well.After filtering the FAERS database, 448 reports were identified that were associated with TdP/QT prolongation when 4 triazoles played the primary suspected role. The AE signals of TdP/QT prolongation for any involved antifungal triazoles were detected by using the 4 detection indicators, and the signals of fluconazole are the strongest. This AE mostly occurred within 0-14 days after triazoles therapy.The AE signals of TdP/QT prolongation associated with antifungal triazoles were very intense. Attention must be paid to the TdP/QT prolongation of various triazoles, particularly at the early stages of antifungal triazoles treatment.

Torsades de pointes (TdP) is an irregular heart rhythm characterized by faster beat rates and potentially could lead to sudden cardiac death. Much effort has been invested in understanding the drug-induced TdP in preclinical studies. However, a comprehensive statistical learning framework that can accurately predict the drug-induced TdP risk from preclinical data is still lacking. We proposed ordinal logistic regression and ordinal random forest models to predict low-, intermediate-, and high-risk drugs based on datasets generated from two experimental protocols. Leave-one-drug-out cross-validation, stratified bootstrap, and permutation predictor importance were applied to estimate and interpret the model performance under uncertainty. The potential outlier drugs identified by our models are consistent with their descriptions in the literature. Our method is accurate, interpretable, and thus useable as supplemental evidence in the drug safety assessment.

OBJECTIVE To study the relationship between hydroxychloroquine (HCQ) use and new-onset atrial fibrillation in patients with systemic lupus erythematosus (SLE). METHODS A retrospective cohort of adult patients with SLE was constructed from December 1, 2014 to May 30, 2017. Patients were categorized as either HCQ users or nonusers. The primary outcome was incident atrial fibrillation. Secondary outcomes included incident ventricular arrhythmias (composite of ventricular tachycardia, ventricular fibrillation, or torsades de pointes). Outcomes were adjudicated by review of the electronic health record. Statistical analyses included simple and multivariable logistic regression tests to estimate the association between HCQ use and incident atrial fibrillation after adjusting for relevant confounders. Propensity score matching analysis was completed. RESULTS Our study included 1,647 patients with SLE, of which 917 were HCQ users and 730 were nonusers. A total of 23 atrial fibrillation events occurred, including 3 in HCQ users and 20 in nonusers. Logistic regression analysis showed an odds ratio (OR) of 0.12 (95% confidence interval [95% CI] 0.034-0.39, P = 0.0005) for incident atrial fibrillation and 2.39 (95% CI 0.25-23.0, P = 0.45) for ventricular arrhythmias. Results remained significant in the fully adjusted and propensity score-matched models. CONCLUSION In this exploratory study, HCQ use was associated with an 88% decrease in the risk of incident atrial fibrillation in patients with SLE. Considering the increased cardiovascular risk in SLE, incorporation of HCQ into the regimen may be beneficial for both disease manifestations and reducing the risk of atrial fibrillation. Further studies would be needed to confirm the antifibrillatory benefit of this relatively safe and low-cost medication.

Nausea is one of the most common and debilitating symptoms Palliative Care patients experience. This can be caused by the life-limiting illness itself, its complications, or its treatments. While there are many options for management, including anti-emetics and motility agents, patients may develop refractory nausea or even intolerance to these treatments. Drug interactions, sedation, extrapyramidal effects, serotonin syndrome, and prolonged QT intervals with risk factors for Torsades de Pointes may all preclude use of these medications. Olfactory distraction using alcohol swabs has supporting literature in the emergency care setting as a means of alleviating nausea in a safe and effective way. We present a case series of 3 patients admitted to a Northwell facility who were referred to the Palliative Care consult service for severe nausea. The patients had nausea of varying etiology and were successfully managed with inhalation of alcohol swabs. This is the first case series that looks into applying this intervention to the Palliative Care population as an easy-to-use, readily-available, and safe method to manage nausea.

Study objective Methadone is associated with QT interval prolongation and torsades de pointes. Expert panel recommendations advocate a pre-methadone electrocardiogram (ECG) and another ECG at 30 days of therapy in patients with risk factors. Some guidelines recommend a pre-methadone ECG and routine ECG monitoring in all methadone patients, but this is controversial due to the resources required. Availability of a convenient, less resource-intensive method of ECG monitoring for patients taking methadone is desirable. The objective of this study was to assess the accuracy of a handheld smartphone ECG (iECG) for QT measurement in patients on maintenance methadone therapy in an urban opioid treatment program. Design Prospective study. Setting Urban opioid treatment program. Patients n = 115 patients in normal sinus rhythm who were on steady-state maintenance methadone therapy INTERVENTION: Patients (n = 115) underwent a simultaneous 12-lead ECG and a single-lead iECG. Measurements and main results The first three QT and RR intervals from lead II of the 12-lead ECG and simulated lead I from the iECG were compared using the Bland-Altman analysis of measurement agreement. Mean [± standard deviation) age was 34 ± 11 years; 71% were female, 75% were white. Compared to the 12-lead ECG, the iECG was associated with a QTc bias of - 0.14 ms (SD = 12 ms, 95% CI = -2.4 to 2.1 ms). The absolute mean difference in QTc between the two methods was 9.5 ± 7.1 ms. For identification of patients with methadone-associated QTc prolongation, the iECG performed moderately well [c-statistic 0.97 (95% CI 0.91-0.99); sensitivity and specificity 75% (95% CI 43-95%) and 99% (95% CI 94-99%), respectively]. The positive and negative likelihood ratios of the iECG for identifying patients with methadone-associated QTc prolongation were 77.25 (95% CI 10.69 to 558.18) and 0.25 (95% CI 0.09 to 0.67), respectively, while the positive and negative predictive values were 90% (95% CI 56-99%) and 97% (95% CI 92-99%), respectively. The accuracy of the iECG for identifying patients with QTc prolongation was 97% (95% CI 91-99%). Conclusion A handheld smartphone ECG is accurate for QT interval measurement in patients taking maintenance methadone therapy, and its performance is moderately good for identifying patients with methadone-associated QTc prolongation.