Ramen noodle neuropathy: an atypical case of partial paralysis from malnutrition.

INTRODUCTION: Due to a COVID-related job loss resulting in financial and food insecurity, a 28-year-old woman initiated a diet consisting solely of one cup of ramen noodles daily for twenty-two months, leading to 27 kg of weight loss. Ramen noodles are low in calories and lack key nutrients, including potassium, chloride, and vitamin B12. CASE DESCRIPTION: The patient presented to the emergency department with acute, worsening weakness and paresthesias in her left wrist and hand. Exam revealed no other abnormalities aside from a cachectic appearance. Labs revealed marked hypokalemia, hypochloremia, lactic acidosis, a mixed metabolic alkalosis with respiratory acidosis, and low levels of zinc and copper. An EKG revealed a prolonged QT interval. After a neurology and psychiatry consult, the patient was admitted for failure to thrive with malnutrition, peripheral neuropathy, hypokalemia, and an acid-base disorder. An MRI of the brain was unremarkable. Studies of other nutritional deficiencies, autoimmune conditions, and sexually transmitted infections were unremarkable. The patient received food and vitamin supplementation, was monitored for re-feeding syndrome, and had a significant recovery. DISCUSSION: After stroke, spinal injury, multiple sclerosis, and the most common focal mononeuropathies were ruled out, the clinical focus turned to nutritional deficiencies, the most significant of which was hypokalemia. Prior research has shown that severe hypokalemia can lead to weakness. It has also shown that chronically insufficient dietary intake is a common cause of hypokalemia. This case, with its partial paralysis of a unilateral upper extremity, may add to the known clinical manifestations of hypokalemia. We review the role of hypokalemia and hypochloremia in acid-base dynamics. Etiologies and clinical manifestations of cobalamin, thiamine, pyridoxine, and copper deficiencies, along with lead toxicity, are also discussed. Diagnostic clarity of mononeuropathies in the context of malnutrition and hypokalemia can be aided by urine potassium levels prior to repletion, neuroimaging that includes the cervical spine, and follow-up electromyography.

Changes in QT Interval in Maintenance Hemodialysis Patients: Pre-Dialysis, One Hour after Initiation of Dialysis, and Post-Dialysis.

INTRODUCTION: This study aimed to evaluate the effects of dialysis on change of QT interval in pre-dialysis, 1 h after dialysis initiation, and post-dialysis period in patients on maintenance dialysis (MHD). METHODS: An observational prospective study was conducted, including 61 patients, on thrice-weekly MHD ≥3 months, and without acute diseases, at the Nephrology-Dialysis Department of a tertiary hospital in Vietnam. The exclusive criteria were atrial fibrillation, atrial flutter, branch block, prolonged QT recorded in medical history, and taking antiarrhythmic drugs lengthening QT interval before entering the study. Twelve-lead electrocardiographs and blood chemistries were done simultaneously before, 1 h after initiation, and after the dialysis session. RESULTS: The proportion of patients with prolonged QT interval increased significantly from 44.3% in pre-dialysis to 77% 1 h after dialysis initiation and 86.9% in post-dialysis session. Immediately after dialysis, the QT and QTc intervals on all 12 leads were significantly longer. Post-dialysis levels of potassium, chloride, magnesium, and urea decreased significantly from 3.97 (0.7), 98.6 (4.7), 1.04 (0.2), and 21.4 (6.1) to 2.78 (0.4), 96.6 (2.5), 0.87 (0.2), and 6.33 (2.8) mmol/L, respectively, whereas the calcium increased significantly from 2.19 (0.2) to 2.57 (0.2) mmol/L. There were significant differences in the potassium level at the dialysis initiation and its speed of reduction between the group without and with prolonged QT interval. CONCLUSIONS: There was an increased risk of prolonged QT interval in MHD patients regardless of the absence of the previous abnormal QT interval. Notably, this risk increased rapidly 1 h after the initiation of dialysis.

Appropriate prescribing of azithromycin for community-acquired pneumonia.

Azithromycin is prescribed for atypical antimicrobial cover in severe community-acquired pneumonia. Inappropriate azithromycin administration incurs unnecessary financial costs, exacerbates antimicrobial resistance and risks QTc interval prolongation leading to cardiac arrhythmias. The present study demonstrated that a majority of patients were prescribed azithromycin without having electrocardiograms to assess the QTc interval and without meeting criteria for severe community-acquired pneumonia based on CURB-65 score.

Treatment of status epilepticus and prolonged QT after massive intentional bupropion overdose with lidocaine.

Bupropion is an atypical antidepressant often used in the treatment of depression, tobacco cessation, seasonal affective disorder, and off label for ADHD. Its primary mechanism of action is by blocking dopamine and norepinephrine reuptake and it is structurally similar to amphetamines. Toxic effects include, most notably and classically, seizures as well as tachycardia, agitation, nausea and vomiting, QT prolongation, QRS widening, hypertension/hypotension. It has a narrow therapeutic window with maximal daily dosing being 450 mg daily. We are reporting the case of a 14-year-old female who ingested 15 g of extended-release bupropion resulting in agitation, status epilepticus, prolonged QT devolving into pulseless Ventricular Tachycardia and briefly V Fib, requiring a total of 5 cardioversions and 1 defibrillation. The QT interval eventually narrowed after supportive care and lidocaine drip. The patient was able to be extubated just two days later with full cognitive function and echocardiogram without cardiac dysfunction. Seizure and cardiotoxicity (including prolonged QT) have been previously described with massive bupropion overdoses. To our knowledge, deterioration to Ventricular Tachycardia and Ventricular Fibrillation with successful treatment and shortening of QT interval with lidocaine bolus and drip has not been reported. Cardiotoxicity related to bupropion has previously been primarily supportive and avoidance of QT prolonging antiarrhythmics such as amiodarone, and at times requiring VA ECMO. Lidocaine has previously been used in tox cases to shorten QT intervals. The hope is for this information to be helpful to other EM and Critical Care providers when placed in similarly difficult circumstances.

Emergency medicine updates: Droperidol.

INTRODUCTION: 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. OBJECTIVE: This paper provides evidence-based updates concerning the use of droperidol for the emergency clinician. DISCUSSION: 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. CONCLUSIONS: Current evidence suggests that droperidol is a safe and effective medication for treating nausea and vomiting, headache, vertigo, and agitation in the ED setting.

Ventricular tachycardia as a consequence of triggered activity.

One of the less frequent underlying mechanisms of ventricular tachycardia (VT) is triggered activity. Triggered activity refers to an extrasystole due to a premature depolarization that occurs when the amplitude of an early or delayed afterdepolarization brings the cardiac membrane to its threshold potential. Hydrochlorothiazide and hydroxyzine can prolong repolarization and QT interval and are associated with early afterdepolarizations. Cyclic AMP-mediated, delayed afterdepolarizations can occur as a result of catecholaminergic surge. Delayed afterdepolarization is classically associated with outflow tract (OT) tachycardia, a type of VT that is uniquely defined by its termination with adenosine. We present a case of triggered OT tachycardia for which intravenous amiodarone through its antiadrenergic effect may have been effective. Infusions of magnesium and a cardioselective, ß-receptor antagonist that does not prolong repolarization may have been more appropriate given the concurrent, acquired prolonged QT syndrome. After initial stabilization, considering the underlying VT mechanism may prompt the clinician to select the most appropriate, further treatment.

A Case Report of Torsade de Pointes and Brugada Pattern Associated with Loperamide Misuse and Supratherapeutic Loperamide Concentrations.

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.

ELECTROCARDIOGRAPHIC CHANGES IN NEWBORNS FROM MOTHERS WITH METABOLIC SYNDROME.

OBJECTIVE: The aim: Analysis of electrocardiographic parameters in newborns from mothers with metabolic syndrome. PATIENTS AND METHODS: Materials and methods: We conducted a prospective cohort trial of 125 newborns, which included the study of their anthropometric, clinical and laboratory indicators and, in particular, ECG parameters. The main group consisted of 40 children, born from mothers with diagnosed metabolic syndrome, the comparison group included 2 subgroups: 28 term newborn and 57 preterm, from mothers without metabolic syndrome. RESULTS: Results: In newborns from mothers with metabolic syndrome on a fragmentary ECG we revealed abnormal depolarization, manifested by changes in the ventricular complex -QRS expansion (p<0.001), impaired conduction (p = 0.004), changes of T wave (p<0.001) and prolonged QT interval (p<0.001). There are such risk factors for QT prolongation in neonates: disease cardiovascular system and disorders of lipid metabolism in mother, asphyxia at birth and electrolyte disorders (hypernatremia OR 0.97), weight too high to gestational age at birth in newborn (OR 2.97), increased blood pressure in the neonatal period (OR 1.07), artificial feeding (OR 3.01). CONCLUSION: Conclusions: Metabolic syndrome in women during pregnancy has a pronounced effect on the cardiovascular system of the newborn. The detected signs of cardiac dysfunction on the ECG can serve as early integrated indicators of metabolic syndrome and cardiovascular disease in children.

A new ECG sign for sudden death: Transient prolonged QT interval following premature contraction. / 一种新的猝死预警心电图：期前收缩后短暂QT间期延长.

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.

Nausea and Vomiting: a Palliative Care Imperative.

PURPOSE OF REVIEW: This review was undertaken to survey recent literature for research reports and comprehensive clinical reviews addressing the pharmacologic management of nausea and vomiting (N&V) in advanced cancer. The goal was to integrate findings in a comprehensive article that incorporates palliative care concepts into antiemetic treatment. RECENT FINDINGS: There are few published studies of N&V in advanced cancer; such research may be limited by the multicausal nature of N&V and participant burden to patients with life-limiting disease. Most articles are written by oncologists who also specialize in palliative care, and those addressing adverse effects of drugs used as antiemetics are found in other literature. Articles addressing more novel therapies, like cannabinoids and medical marijuana, are uncommon in the oncology literature. N&V in patients with progressive or advanced cancer is often multicausal. Nausea is more common and persistent, and even mild nausea is bothersome and may cause anxiety or depression. The mechanisms of nausea and vomiting overlap, but different neural pathways constitute the final pathway for each-the brainstem for vomiting and higher brain regions for nausea. Common causes of N&V in advanced cancer include constipation, opioids, and malignant bowel obstruction. About 40% have undetermined causes and may be exacerbated by impaired gastric emptying, chemical imbalances, or other factors. Several drugs that have antiemetic effects and act at different receptors are used to palliate N&V. There is a paucity of research that supports palliative antiemetic choices, and other research is needed to define potential therapeutic strategies that capitalize on differences between nausea and vomiting.

Hypertension and QT interval prolongation associated with targeted systemic cancer therapies.

OBJECTIVE: To summarize the proposed mechanisms behind hypertension and QT interval prolongation associated with use of targeted systemic cancer therapies and provide recommendations for monitoring or managing these toxicities. SUMMARY: The cardiotoxic effects of targeted systemic cancer therapies represents a new paradigm of cancer treatment associated cardiovascular adverse events. National guidelines regarding optimal monitoring and management strategies for hypertension and QT interval prolongation associated with use of these therapies are lacking. While the pathophysiological drivers of hypertension due to targeted systemic cancer therapies differ by class of targeted therapy, general management strategies do not. Routine blood pressure monitoring throughout the duration of therapy is recommended for all agents. Patients who experience hypertension often can be treated with the addition or modification of antihypertensive therapies. Uncontrolled hypertension despite optimal medical management may require dose modifications or discontinuation of the targeted systemic cancer therapy. Electrocardiogram monitoring is recommended for patients who receive targeted therapies that may prolong the QT interval. Minimizing or managing drug interactions with other QT prolonging medications is recommended in addition to ensuring adequate electrolyte supplementation. Dose modifications or discontinuation of the targeted systemic therapy may be necessary for patients who experience QT interval prolongation. CONCLUSIONS: Appropriate cardiovascular monitoring and timely management of treatment-emergent toxicities can optimize therapy for patients receiving targeted systemic cancer therapies associated with a risk of drug-induced hypertension or QT interval prolongation.

Prolonged QT Interval in Patients Receiving Psychotropic Medications.

INTRODUCTION: Prolonged QT interval (PQTI) is a cardiac condition widely documented in the mental health literature and linked to psychotropic medication use. Medications notable for contributing to the condition are antipsychotics, antidepressants, and some mood stabilizers. Although additional medication classes and other contributing risk factors are often present, the prudent mental health provider benefits from having a basic understanding of this condition and how to prevent and manage it with safe prescribing practices. AIMS: This guide seeks to provide mental health prescribers with a basic understanding of the risk factors, pathophysiology, identification, and management of PQTI. METHOD: Relevant literature and practice guidelines were reviewed and summarized with a focus on practical interventions for the psychiatric mental health nurse practitioner (PMHNP). RESULTS: One of the primary contributing factors to PQTI development and complications is polypharmacy. Patients with co-occurring medical, mental health, and/or substance use disorders may receive medications from multiple providers. Anticancer drugs, antiarrhythmic medications, and even a number of common antibiotics can increase the QT interval, making it a challenge for even the most experienced mental health provider to monitor medication interactions and side effects that contribute to PQTI. Having a sound knowledge base of these factors can guide safe PMHNP practice. CONCLUSIONS: Decision-making trees grounded in evidence-based research were developed in order to direct thorough assessment and safe treatment of patients requiring psychotropic medications.

Mutational and phenotypic spectra of KCNE1 deficiency in Jervell and Lange-Nielsen Syndrome and Romano-Ward Syndrome.

KCNE1 encodes a regulatory subunit of the KCNQ1 potassium channel-complex. Both KCNE1 and KCNQ1 are necessary for normal hearing and cardiac ventricular repolarization. Recessive variants in these genes are associated with Jervell and Lange-Nielson syndrome (JLNS1 and JLNS2), a cardio-auditory syndrome characterized by congenital profound sensorineural deafness and a prolonged QT interval that can cause ventricular arrhythmias and sudden cardiac death. Some normal-hearing carriers of heterozygous missense variants of KCNE1 and KCNQ1 have prolonged QT intervals, a dominantly inherited phenotype designated Romano-Ward syndrome (RWS), which is also associated with arrhythmias and elevated risk of sudden death. Coassembly of certain mutant KCNE1 monomers with wild-type KCNQ1 subunits results in RWS by a dominant negative mechanism. This paper reviews variants of KCNE1 and their associated phenotypes, including biallelic truncating null variants of KCNE1 that have not been previously reported. We describe three homozygous nonsense mutations of KCNE1 segregating in families ascertained ostensibly for nonsyndromic deafness: c.50G>A (p.Trp17*), c.51G>A (p.Trp17*), and c.138C>A (p.Tyr46*). Some individuals carrying missense variants of KCNE1 have RWS. However, heterozygotes for loss-of-function variants of KCNE1 may have normal QT intervals while biallelic null alleles are associated with JLNS2, indicating a complex genotype-phenotype spectrum for KCNE1 variants.

Interictal cardiac repolarization abnormalities in people with epilepsy.

BACKGROUND AND OBJECTIVE: The occurrence of cardiac electrical abnormalities such as repolarization disorders in patients with epilepsy was previously documented and may, in part, clarify the mechanism of sudden unexpected death in those patients. The aim of this study was to investigate the frequency of cardiac repolarization disorders among patients with epilepsy and whether specific demographic- or disease-related features were associated with their occurrence. SUBJECTS AND METHODS: This cross-sectional study was carried out on 1000 subjects with epilepsy who were compared with age- and sex-matched 2500 subjects without epilepsy. Clinical assessment, which included careful history taking and examination, was carried out for all participants in addition to resting 12-lead electrocardiogram (ECG) recording. Electrocardiograms were reviewed by experienced cardiologists. Electrocardiogram intervals were measured, and morphological abnormalities were identified using standard guidelines. RESULTS: Repolarization abnormalities were found in 142 (14.2%) patients with epilepsy. A statistically significant elevation in percentage of corrected QT interval (QTc) prolongation (both severe and borderline) among patients with epilepsy compared with controls was documented (8.4% vs 2%, P<0.001). Epilepsy increased the likelihood of hosting prolonged QTc more than 4 times (95% confidence interval: 3.175-6.515; odds ratio: 4.548; P<0.001). Affected patients were significantly older (95% confidence interval: 1.012-1.044; odds ratio: 1.027; P=0.001), and the abnormality was significantly more prevalent among those with poor seizure control (95% confidence interval: 1.103-2.966; odds ratio: 1.809; P=0.019). On the other hand, early repolarization (ER) pattern and Brugada type ECG pattern (BP) were significantly more prevalent in subjects without epilepsy. CONCLUSIONS: Corrected QT interval prolongation (both severe and borderline) was more prevalent among patients with epilepsy, especially if uncontrolled or elderly. Electrocardiogram should be established as a part of the diagnostic workup of epilepsy in order to identify such electrocardiographic abnormality.

Evaluation of Prolonged QT Interval: Structural Heart Disease Mimicking Long QT Syndrome.

BACKGROUND: In about 20-25% of patients with congenital long QT syndrome (LQTS) a causative pathogenic mutation is not found. The aim of this study was to explore the prevalence of alternative cardiac diagnoses among patients exhibiting prolongation of QT interval with negative genetic testing for LQTS genes. METHODS: We conducted a retrospective analysis of 239 consecutive patients who were evaluated in the inherited arrhythmia clinic at the Toronto General Hospital between July 2013 and December 2015 for possible LQTS. A detailed review of the patients' charts, electrocardiograms, and imaging was carried out. RESULTS: The analysis included 56 gene-negative patients and 61 gene-positive patients. Of the gene-negative group, 25% had structural heart disease compared to only 1.6% of gene-positive patients (P < 0.001). Structural heart disease was more likely if only one abnormal QTc parameter was found in the course of the evaluation (35.2% vs 9.1%, P = 0.01). The most common structural cardiac pathology was bileaflet mitral valve prolapse (8.9%). No gene-positive patient had episodes of nonsustained ventricular tachycardia, compared to seven of the gene-negative patients (0% vs 12.5%, P = 0.005). CONCLUSIONS: Structural pathology was detected in a quarter of gene-negative patients evaluated for possible LQTS. Hence, cardiac imaging and Holter monitoring should be strongly encouraged to rule out structural heart disease in this population.

Providers' Response to Clinical Decision Support for QT Prolonging Drugs.

Commonly used drugs in hospital setting can cause QT prolongation and trigger life-threatening arrhythmias. We evaluate changes in prescribing behavior after the implementation of a clinical decision support system to prevent the use of QT prolonging medications in the hospital setting. We conducted a quasi-experimental study, before and after the implementation of a clinical decision support system integrated in the electronic medical record (QT-alert system). This system detects patients at risk of significant QT prolongation (QTc>500ms) and alerts providers ordering QT prolonging drugs. We reviewed the electronic health record to assess the provider's responses which were classified as "action taken" (QT drug avoided, QT drug changed, other QT drug(s) avoided, ECG monitoring, electrolytes monitoring, QT issue acknowledged, other actions) or "no action taken". Approximately, 15.5% (95/612) of the alerts were followed by a provider's action in the pre-intervention phase compared with 21% (228/1085) in the post-intervention phase (p=0.006). The most common type of actions taken during pre-intervention phase compared to post-intervention phase were ECG monitoring (8% vs. 13%, p=0.002) and QT issue acknowledgment (2.1% vs. 4.1%, p=0.03). Notably, there was no significant difference for other actions including QT drug avoided (p=0.8), QT drug changed (p=0.06) and other QT drug(s) avoided (p=0.3). Our study demonstrated that the QT alert system prompted a higher proportion of providers to take action on patients at risk of complications. However, the overall impact was modest underscoring the need for educating providers and optimizing clinical decision support to further reduce drug-induced QT prolongation.

Quinine and the ABCs of Long QT: A Patient's Misfortune with Arthritis, (Alcoholic) Beverages, and Cramps.

A 91-year-old woman presented to the emergency department by ambulance after her family found her minimally responsive. Telemetry monitoring demonstrated episodes of non-sustained polymorphic ventricular tachycardia (PMVT) associated with significantly prolonged repolarization. Her medical history revealed that she was taking quinine or a derivative in three different forms: hydroxychloroquine, quinine sulfate (for leg cramps), and her gin mixed with tonic water (containing quinine). The present case is illustrative of classic etiologies and findings of acquired long QT syndrome, and serves as an important reminder for providers to take a complete medication history, including use of duplicative and alternative medicines and type of alcohol consumption.

A neonatal prolonged QT syndrome due to maternal use of oral tricyclic antidepressants.

UNLABELLED: It is known that tricyclic antidepressants induce long QT intervals associated with forms of life-threatening arrhythmia such as torsades de pointes (TdP), and these adverse effects may also occur in neonates whose mothers take tricyclic antidepressants. We report a neonatal case of prolonged QT interval and TdP caused by clomipramine that was transferred transplacentally from the mother. Administration of magnesium sulfate was effective to abolish TdP. CONCLUSION: When mothers take tricyclic antidepressants during pregnancy, their newborns should be watched carefully for drug-induced long QT syndrome and TdP. WHAT IS KNOWN: •Tricyclic antidepressant can prolong the QT interval. It may be used for depression in pregnancy. What is New: •This is the first neonatal case report of prolonged QT interval and TdP caused by clomipramine transferred transplacentally from the mother.

Risk for prolonged QT interval and associated outcomes in children with early restrictive eating patterns.

UNLABELLED: Aim This study aimed to describe the frequency of QTc prolongation in children with restrictive eating disorders early in the course of disease admitted for inpatient therapy, to determine the frequency of associated ventricular arrhythmia, and to evaluate the relationship between QTc interval and concomitant electrolyte abnormalities and rate of weight loss. METHODS: This was a retrospective cohort study of patients aged 11-25 years with early restrictive eating disorders. RESULTS: In all, 82 patients met the inclusion criteria (84% female). In total, 9.8% had prolonged QTc interval during hospitalisation. Patients with prolonged QTc had significantly higher resting heart rates (p=0.006), but there was no association with hypokalaemia (p=0.31), hypomagnesaemia (p=0.43), hypophosphataemia (p=1), or rate of weight loss (p=1). CONCLUSION: Mild QTc prolongation in patients with restrictive eating disorders is not related to electrolyte abnormalities or rate of weight loss in this population, suggesting that investigation about other potential risk factors of prolonged QTc interval may be warranted.

Metoprolol and diltiazem ameliorate ziprasidone-induced prolonged corrected QT interval in rats.

Ziprasidone, an atypical antipsychotic agent, has been shown to increase the corrected QT (QTc) interval in some patients. The aim of this study was to reveal the effects of metoprolol and diltiazem on ziprasidone drug-induced prolonged QTc interval. A total of 24 rats were equally divided into the following four groups: the first group was used as the control and received 1 mL/kg saline; 3 mg/kg ziprasidone and saline were administered to the second group; 3 mg/kg ziprasidone and 1 mg/kg metoprolol were administered to the third group and 3 mg/kg ziprasidone and 2 mg/kg diltiazem were administered to the fourth group. Two hours following application of the drugs, the QTc was calculated by performing electrocardiography in derivation (D)I. The duration of QTc interval was compared among the four groups. The mean QTc intervals were significantly increased in the third and fourth groups compared with the second group (p < 0.0005 and p < 0.0001, respectively). The study demonstrated the effectiveness of metoprolol and diltiazem in the prevention of ziprasidone-induced elongation in the QTc interval. Both metoprolol and diltiazem may be considered in the prophylactic therapy of high-risk patients who are using ziprasidone.