Serum Magnesium Levels and QTc Interval Prolongation As Prognostic Markers in Acute Myocardial Infarction: A Randomized Controlled Study.

Introduction Acute myocardial infarction (AMI) is frequently preceded by arrhythmias, which continue to be a prominent cause of abrupt fatality in AMI. Abnormal magnesium levels have been linked to the emergence of arrhythmia because it enhances myocardial metabolism and cardiac output and prevents calcium buildup and myocardial cell death by lowering arrhythmias. The objectives of this study were to evaluate serum magnesium levels and QTc interval as prognostic indicators in AMI patients during the initial 48 hours of hospital stay and to correlate these parameters with the Global Registry of Acute Coronary Events (GRACE) scoring. We studied AMI patients by dividing them into two groups: those with abnormal and those with normal serum magnesium levels. Methods After obtaining ethical approvals, patients were subjected to detailed history, which included sociodemographic details, drug history, clinical examination, and investigations such as creatine kinase myocardial band (CK-MB), CK-total, troponin-T, ECG (QTc interval), two-dimensional echocardiogram (2D-ECHO), serum creatinine and magnesium levels, heart rate, and blood pressure. We also calculated the GRACE score for all patients. Results We found that patients in the age group of 51-60 years were more prone to developing arrhythmias, and while AMI was more prevalent in males, the occurrence of arrhythmias was slightly higher in females with AMI. Anterior wall motion abnormality (AWMA) was the most predominant abnormality, and 12.3% of AWMA patients had arrhythmias. QTc interval was significantly longer in patients who developed arrhythmias. Interestingly, among patients with QTc prolongation, 35% patients had abnormal magnesium levels, while 65% had normal magnesium levels. In our study, of the 25 patients with hypermagnesemia, nine (36%) developed arrhythmias, while of the 75 patients with hypomagnesemia, 15 (20%) patients developed arrhythmias. Interestingly, we found that there was a positive correlation between GRACE score and serum magnesium as well as QTc interval prolongation. Lastly, among the six deaths reported, three (50%) patients had arrhythmias. Conclusion Overall, we conclude that serum magnesium levels play a pivotal role as a prognostic tool for arrhythmias and are a useful investigation during the initial 48 hours of admission in AMI patients.

Concentration-QTc analysis of soticlestat in healthy adults: An alternative to a thorough QT study.

AIM: This study aimed to examine the cardiac and overall safety and pharmacokinetic (PK) profiles of soticlestat (TAK-935), an oral, first-in-class selective cholesterol 24-hydroxylase inhibitor. METHODS: Data came from a randomised, phase 1 study of soticlestat in 33 healthy Japanese adults (NCT04461483); 24 adults in Part 1 (single-dose soticlestat 200-1200 mg or placebo) and 9 in Part 2 (soticlestat 100-300 mg twice daily or placebo for 21 days). PK sample collection was paired with 12-lead electrocardiogram data from continuous Holter recordings. The concentration-QTc relationship was analysed using a linear mixed-effects model. QTc prolongation safety margins were determined for two scenarios of calculated high clinical exposures: scenario 1 (NCT05064449) involved coadministration of single-dose soticlestat 300 mg with itraconazole or mefenamic acid and scenario 2 (NCT05098054) involved single-dose soticlestat 300 mg administration in participants with mild/moderate hepatic impairment (implementing a 3-fold dose reduction for moderate severity). RESULTS: Based on concentration-QTc analysis, placebo-corrected change-from-baseline QT values (90% confidence intervals), corrected for heart rate (Fridericia's method), were 0.94 ms (-2.35, 4.23) for soticlestat and 0.63 ms (-3.15, 4.41) for its N-oxide metabolite plasma concentrations at therapeutic doses (soticlestat 300 mg twice daily); safety margins were >2-fold for scenarios of calculated high clinical exposures. No (Part 1) and five (83.3%; Part 2) participants experienced treatment-emergent adverse events (all mild). CONCLUSION: There was no evidence for QT prolongation with soticlestat at therapeutic doses or in two scenarios of high clinical exposures, which resulted in regulatory agencies waiving requirements of a thorough QT study. Safety/PK findings aligned with previous soticlestat clinical studies.

Repolarization Injury and Occurrence of Torsades de Pointes During Acute Takotsubo Syndrome.

Background: During takotsubo syndrome (TS), QTc prolongation is common, reflecting repolarization injury and providing the substrate for torsades de pointes (TdP). TdP has been reported sporadically in TS, yet QTc prolongation and TdP risk are often overlooked during management. Objectives: In TS patients, we sought to document TdP incidence, characteristics of patients with TdP, and association of QTc with postdischarge survival. Methods: Among consecutive TS patients at a single institution, we documented admission and discharge QTc, TdP incidence, and postdischarge 1-year mortality from 2006 to 2019. For perspective regarding TdP-TS risk, we characterized all published TdP cases from 2003 to 2022. Results: Of 259 patients, median age was 68 (range: 59-77) years; 92% were female. The QTc interval was prolonged (≥460 ms) on admission in 129 (49.8%) patients and at discharge in 140 (54%) patients. QTc was ≥500 ms either on admission or at discharge in 98 (37.8%) patients. In-hospital TdP incidence was 0.8%. Postdischarge mortality was associated with admission but not discharge, QTc: <460 ms (1.6%); 460-499 ms (12.6%); ≥500 ms (8.8%); P = 0.0056. Among 38 published TdP-TS cases, 80% of TdP events were within 48 hours of hospitalization, 90% of events occurred with QTc ≥500 ms, and 47.5% of events occurred with QTc ≥600 ms. Conditions associated with TdP risk were present in fewer than one-third of patients. Conclusions: During TS, QTc ≥500 ms was frequent. TdP incidence was low, with unpredictable occurrence and observed almost entirely with QTc ≥500 ms. A normal admission QTc was associated with >98% survival at 1-year postdischarge.

Does IV fentanyl, frequently used in emergency departments, change QTC value? A prospective observational study.

BACKGROUND: Fentanyl is an opioid analgesic frequently used in the emergency department (ED) and is usually administered without knowing the QTC values of the patients or being monitored. However, the effect of fentanyl on QTC, prolongation or shortening, has not been elucidated. This study aimed to determine the effect of fentanyl on QTC. METHODS: This is a prospective observational study in the ED of a tertiary hospital on patients who received intravenous fentanyl for procedures other than intubation. ECG was performed before and at 1, 5, 15, 30, and 60 min after the initiation of fentanyl administration, and QTC value was calculated. Primary outcomes were QTC prolongation, defined as an increase in the QTC to ≥ 500 ms or any increase in QTC by ≥ 60 ms. RESULTS: The study included 109 patients. Of these, 60 patients were male, and the median age was 40. Compared with the baseline QTC value, statistically significant prolongation was detected at the 5th, 15th, 30th, and 60th minutes, with the maximum prolongation at 30 min, and the median was 13.08 ms. Most patients with QTC prolongation were female and over 40 years of age. Clinically, none of these patients developed malignant arrhythmias during the 60-minute monitored observation period. CONCLUSION: Fentanyl prolonged the QTC value statistically significantly. Although no patient developed malignant arrhythmia clinically, our results suggest that this QTC-prolonging effect should be considered when using fentanyl in patients at risk of torsades.

Congenital Long QT Syndrome Unmasked by Albuterol in an Adolescent with Asthma.

BACKGROUND: Patients with congenital long QT syndrome (LQTS) are prone to ventricular dysrhythmia but may be initially asymptomatic with a normal QTc interval on resting electrocardiogram (ECG). Albuterol is listed as a medication that poses a "special risk" to patients with congenital LQTS, but its effects have been rarely described. We present a case of previously unknown, asymptomatic congenital LQTS unmasked by albuterol in an adolescent with asthma. CASE REPORT: A 12-year-old girl with a history of asthma presented to the emergency department (ED) with shortness of breath, wheezing, and tachycardia for 24 h, consistent with acute asthma exacerbation. She received two doses of her home albuterol inhaler 2 h prior to presentation. Initial ECG demonstrated a QTc of 619 ms. Her remaining history, clinical examination, and laboratory workup, including electrolytes, were unremarkable. She was observed with cardiac monitoring before being discharged from the ED in stable condition for next-day outpatient pediatric cardiology follow-up. Resting office ECGs revealed QTcs from 440-470 ms. Exercise stress test revealed QTc prolongation of 520 ms and 500 ms at minute-2 and minute-4 of recovery, respectively. Genetic testing revealed heterozygous pathogenic variants in KCNQ1, consistent with type 1 LQTS. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Albuterol may be a cause of marked QTc prolongation in ED patients with underlying congenital LQTS, which can be a diagnostic clue in previously unidentified patients. Extreme QTc prolongation also serves as an indication in the ED for Cardiology consultation, laboratory evaluation for electrolyte imbalances, and observation with cardiac monitoring.

A Comparative Analysis of the Effects of Haloperidol and Dexmedetomidine on QTc Interval Prolongation during Delirium Treatment in Intensive Care Units.

Background: Haloperidol and dexmedetomidine are used to treat delirium in the intensive care unit (ICU). The effects of these drugs on the corrected QT (QTc) interval have not been compared before. It was aimed to compare the effects of haloperidol and dexmedetomidine treatment on QTc intervals in patients who developed delirium during ICU follow-up. Method: The study is single-center, randomized, and prospective. Half of the patients diagnosed with delirium in the ICU were treated with haloperidol and the other half with dexmedetomidine. The QTc interval was measured in the treatment groups before and after drug treatment. The study's primary endpoints were maximal QT and QTc interval changes after drug administration. Results: 90 patients were included in the study, the mean age was 75.2±12.9 years, and half were women. The mean time to delirium was 142+173.8 hours, and 53.3% of the patients died during their ICU follow-up. The most common reason for hospitalization in the ICU was sepsis (%37.8.). There was no significant change in QT and QTc interval after dexmedetomidine treatment (QT: 360.5±81.7, 352.0±67.0, p= 0.491; QTc: 409.4±63.1, 409.8±49.7, p=0.974). There was a significant increase in both QT and QTc interval after haloperidol treatment (QT: 363.2±51.1, 384.6±59.2, p=0.028; QTc: 409.4±50.9, 427.3±45.9, p=0.020). Conclusions: Based on the results obtained from the study, it can be concluded that the administration of haloperidol was associated with a significant increase in QT and QTc interval. In contrast, the administration of dexmedetomidine did not cause a significant change in QT and QTc interval.

QTc Interval Prolongation as an Adverse Event of Azole Antifungal Drugs: Case Report and Literature Review.

QTc prolongation and torsade de pointes (TdP) are significant adverse events linked to azole antifungals. Reports on QTc interval prolongation caused by these agents are limited. In this study, we report a case of a 77-year-old male with cardiovascular disease who experienced QTc prolongation and subsequent TdP while being treated with fluconazole for Candida albicans-induced knee arthritis. Additionally, a literature review was conducted on cases where QTc prolongation and TdP were triggered as adverse events of azole antifungal drugs. The case study detailed the patient's experience, whereas the literature review analyzed cases from May 1997 to February 2023, focusing on patient demographics, underlying diseases, antifungal regimens, concurrent medications, QTc changes, and outcomes. The review identified 16 cases, mainly in younger individuals (median age of 29) and women (75%). Fluconazole (63%) and voriconazole (37%) were the most common agents. Concurrent medications were present in 75% of cases, and TdP occurred in 81%. Management typically involved discontinuing or switching antifungals and correcting electrolytes, with all patients surviving. Risk assessment and concurrent medication review are essential before starting azole therapy. High-risk patients require careful electrocardiogram monitoring to prevent arrhythmias. Remote monitoring may enhance safety for patients with implanted devices. Further studies are needed to understand risk factors and management strategies.

Loperamide-Induced Torsades de Pointes.

Loperamide is a readily available, over-the-counter medication used to treat diarrhea. At therapeutic doses, loperamide exerts its effects mainly on the intestinal opioid receptors with minimal psychoactive effects; however, at supratherapeutic doses, it reaches central opioid receptors. With tighter regulations on opioid prescriptions, loperamide has emerged as a popular drug of abuse among opioid users. At supratherapeutic doses, loperamide can cause severe cardiac toxicity, resulting in wide QRS rhythms, severe bradycardia, prolonged QTc, polymorphic ventricular tachycardia, and cardiac arrest. We present the case of a 27-year-old female with a history of heroin abuse who suffered torsades de pointes resulting in cardiac arrest in the setting of a loperamide overdose.

An interesting case series of ticagrelor induced long QTc.

This case series explores three patients who underwent percutaneous coronary intervention (PCI) and experienced prolonged QT intervals under treatment with Ticagrelor. The first case was a female who presented with chest pain and received a Xience stent. The second case involved a male patient who received two Xience stents. The third case was that of a male patient with LAD stenosis. All three patients received Ticagrelor and exhibited prolonged QTc intervals on their electrocardiograms (ECGs), which was resolved after switching to Clopidogrel. Thus far, the potential impact of Ticagrelor on QT prolongation has not been adequately addressed in the literature. It is hypothesized that Ticagrelor can block adenosine uptake by red blood cells, which may explain QTc prolongation. The results of this case series indicate that Ticagrelor may prolong QTc intervals. Consequently, it is imperative that clinicians are aware of this previously unlisted side effect and that patients are closely monitored while seeking alternative medications to manage the condition.

No QTc prolongation with CDK 4/6 inhibitor FCN-437c: results of a concentration-QTc analysis from a dedicated study in adult healthy subjects.

Cardiotoxicity and QT interval prolongation have been a common cause of withdrawal of drugs from the market. FCN-437c is an oral, second-generation, potent, and selective CDK4/6 inhibitor for the treatment of patients with HR+/HER2- metastatic breast cancer. A single-center, double-blind, randomized, and placebo-controlled clinical study in healthy subjects was conducted to investigate the QTc prolongation potential of FCN-437c utilizing Concentration-QTc (C-QTc) modeling approach. FCN-437c was administered at doses of 300, and 400 mg with single oral administration, along with placebo, in 18 healthy subjects. Electrocardiograms (ECGs) through 24 h holter monitor and blood samples were collected. The Cmax of 400 mg single dose in healthy subjects is similar to that from therapeutic dose 200 mg QD at steady state in patients with cancer. The 90% CI upper limit of ΔΔQTcF at the Cmax geometric mean in both dose groups were <10 ms. It is concluded that FCN-437c has low risk of prolonging the QT interval at therapeutic dose. Systematic Review Registration: https://clinicaltrials.gov/study/NCT06290466?term=NCT06290466&rank=1, identifier [NCT06290466].

Prevalence, Outcomes, and Predictors of Prolonged Corrected QT Interval in Hydroxychloroquine-Naïve Hospitalized COVID-19 Patients.

The studies regarding prevalence, outcomes, and predictors of prolonged corrected QT (QTc) among COVID-19 patients not on QTc-prolonging medication are not available in the literature. In this retrospective cohort study, the QTc of 295 hospital-admitted COVID-19 patients was analyzed and its association with in-hospital mortality was determined. The QTc was prolonged in 14.6% (43/295) of the study population. Prolonged QTc was seen in patients with older age (P = 0.018), coronary artery disease (P = 0.001), congestive heart failure (P = 0.042), elevated N-terminal-pro-B-type natriuretic peptide (NT-ProBNP) (P < 0.0001), and on remdesivir (P = 0.046). No episode of torsades de pointes arrhythmia or any arrhythmic death was observed among patients with prolonged QTc. The mortality was significantly high in patients with prolonged QTc (P = 0.003). The multivariate logistic regression analysis showed coronary artery disease (odds ratio (OR): 4.153, 95% CI 1.37-14.86; P = 0.013), and NT-ProBNP (ng/L) (OR: 1.000, 95% CI 1.000-1.000; P = 0.007) as predictors of prolonged QTc. The prolonged QTc was associated with the worst in-hospital survival (p by log-rank 0.001). A significant independent association was observed between prolonged QTc and in-hospital mortality in multivariate cox-regression analysis (adjusted hazard ratio: 3.861; (95% CI 1.719-6.523), P < 0.0001). QTc was found to be a marker of underlying comorbidities among COVID-19 patients. Prolonged QTc in hospitalized COVID-19 patients was independently associated with in-hospital mortality.

Hydroxychloroquine-azithromycin, doubase C, and QTc prolongation in congolese patients with COVID-19: Myth or reality?

BACKGROUND: QTc interval prolongation with an increased risk of torsade de pointes (Tsd) has been described in coronavirus disease 2019 (COVID-19) patients treated with hydroxychloroquine (HCQ) and azithromycin (AZI) in Western countries. In the DR Congo, few studies have evaluated the safety of this association or proposed new molecules. AIM: To determine the incidence of QTc prolongation and Tsd in COVID-19 patients treated with HCQ-AZIs vs doubase C (new molecule). METHODS: In present randomized clinical trial, we have included patients with mild or moderate COVID-19 treated with either HCQ-AZI or doubase C. Electrocardiogram (ECG) changes on day 14 of randomization were determined based on pretreatment tracing. Prolonged QTc was defined as ≥ 500 ms on day 14 or an increase of ≥ 80 ms compared to pretreatment tracing. Patients with cardiac disease, those undergoing other treatments likely to prolong QTc, and those with disturbed ECG tracings were excluded from the study. RESULTS: The study included 258 patients (mean age 41 ± 15 years; 52% men; 3.4% diabetics, 11.1% hypertensive). Mild and moderate COVID-19 were found in 93.5% and 6.5% of patients, respectively. At baseline, all patients had normal sinus rhythm, a mean heart rate 78 ± 13/min, mean PR space 170 ± 28 ms, mean QRS 76 ± 13 ms, and mean QTc 405 ± 30 ms. No complaints suggesting cardiac involvement were reported during or after treatment. Only four patients (1.5%) experienced QTc interval prolongation beyond 500 ms. Similarly, only five patients (1.9%) had an increase in the QTc interval of more than 80 ms. QTc prolongation was more significant in younger patients, those with high viral load at baseline, and those receiving HCQ-AZI (P < 0.05). None of the patients developed Tsd. CONCLUSION: QTc prolongation without Tsd was observed at a lower frequency in patients treated with HCQ-AZI vs doubase C. The absence of comorbidities and concurrent use of other products that are likely to cause arrhythmia may explain our results.

Safety of outpatient commencement of sotalol.

Background: Inpatient monitoring is recommended for sotalol initiation. Objective: The purpose of this study was to assess the safety of outpatient sotalol commencement. Methods: This is a multicenter, retrospective, observational study of patients initiated on sotalol in an outpatient setting. Serial electrocardiogram monitoring at day 3, day 7, 1 month, and subsequently as clinically indicated was performed. Corrected QT (QTc) interval and clinical events were evaluated. Results: Between 2008 and 2023, 880 consecutive patients who were commenced on sotalol were evaluated. Indications were atrial fibrillation/flutter in 87.3% (n = 768), ventricular arrhythmias in 9.9% (n = 87), and other arrhythmias in 2.8% (n = 25). The daily dosage at initiation was 131.0 ± 53.2 mg/d. The QTc interval increased from baseline (431 ± 32 ms) to 444 ± 37 ms (day 3) and 440 ± 33 ms (day 7) after sotalol initiation (P < .001). Within the first week, QTc prolongation led to the discontinuation of sotalol in 4 and dose reduction in 1. No ventricular arrhythmia, syncope, or death was observed during the first week. Dose reduction due to asymptomatic bradycardia occurred in 3 and discontinuation due to dyspnea in 3 within the first week. Overall, 1.1% developed QTc prolongation (>500 ms/>25% from baseline); 4 within 3 days, 1 within 1 week, 4 within 60 days, and 1 after >3 years. Discontinuation of sotalol due to other adverse effects occurred in 41 patients within the first month of therapy. Conclusion: Sotalol initiation in an outpatient setting with protocolized follow-up is safe, with no recorded sotalol-related mortality, ventricular arrhythmias, or syncope. There was a low incidence of significant QTc prolongation necessitating discontinuation within the first month of treatment. Importantly, we observed a small incidence of late QT prolongation, highlighting the need for vigilant outpatient surveillance of individuals on sotalol.

Case report: Phosphoinositide 3-kinase inhibitor with fulvestrant in a patient with ER+/HER2- metastatic breast carcinoma induced fatal arrhythmias: a preventable event?

Phosphoinositide 3-kinase (PI3K) inhibitors have shown synergistic anticancer effects with endocrine therapy against ER+/PIK3CA-mutated breast cancer. PI3K inhibitors for cancer therapy are becoming more common. There is an increasing need to understand their cardiac adverse events. In this report, we describe the features of near-fatal mixed arrhythmias in a patient who was undergoing a phase Ib clinical study of PI3Kα inhibitor with fulvestrant. Subsequently, the patient survived by cardiopulmonary resuscitation and therefore did not die. This case highlights that PI3K inhibitors can induce QT/QTc prolongation and predispose patients to TdP. The combination of QT/QTc prolongation in combination with prolonged cardiac repolarization, such as an AV block during treatment with PI3Kα inhibitor, may aggravate the occurrence of TdP. It is likely to be a safer strategy to adjust the standard of discontinuing drugs and continuing drugs (QTc interval was <500 and <60 ms at baseline) or choose other types of alternative treatment options. This report provided some ideas for clinicians to identify early and prevent the occurrence of fatal arrhythmias during anticancer treatment.

Comparison of electrocardiogram and blood pressure recording methods in non-rodent toxicology studies: A retrospective analysis.

Our study retrospectively examines 51 non-rodent general toxicology studies conducted over the past 8 years to ascertain the influence of recording methodologies on baseline cardiovascular (CV) parameters and statistical sensitivity. Specifically, our work aims to evaluate the frequency of cardiovascular parameter recording categorized by therapeutic modality and study type, to assess the variability in these parameters based on measurement techniques, and to determine the sample sizes needed for detecting relevant changes in heart rate (HR), blood pressure (BP), and QTc interval in non-human primate (NHP) studies. Results indicate that electrocardiogram (ECG) measurements in dogs and NHP were recorded in 63% of studies, combined with BP recording in 18% of studies, while BP was never recorded alone. Trend analysis reveals a decline in the utilisation of restraint-based methods for ECG measurements post-2017, to the benefit of telemetry-based recordings, particularly Jacketed External Telemetry (JET). There was a marked difference in baseline values, with restraint-based methods showing significantly higher HR and QTc values compared to JET, likely linked to animal stress. Further analysis suggests an unrealistic and unethical sample size requirement in NHP studies for detecting biologically meaningful CV parameter changes using restraint-based methods, while JET methods necessitate significantly smaller sample sizes. This retrospective study indicates a notable shift from snapshots short-duration, restraint-based methods towards telemetry approaches over the recent years, especially with an increased usage of implanted telemetry. The transition contributes to potential consensus within industry or regulatory frameworks for optimal practices in assessing ECG, HR, and BP in general toxicology studies.

Early identification of severe immune checkpoint inhibitor associated myocarditis: From an electrocardiographic perspective.

OBJECTIVES: Immune checkpoint inhibitor (ICI)-associated myocarditis, particularly severe ICI-associated myocarditis, has a high mortality rate. However, the predictive value of electrocardiogram (ECG) remains unclear. The present study aimed to evaluate the predictive value of clinical and electrocardiographic parameters for severe myocarditis. METHODS: Clinical and electrocardiographic data of 73 cancer patients with ICI-associated myocarditis were retrospectively collected. The severity of ICI-associated myocarditis was graded using the NCCN guidelines for managing immunotherapy-related toxicities. Myocarditis grades 1-2 and grades 3-4 were classified as mild and severe myocarditis, respectively. Logistic regression analysis was performed to analyze the predictive value of each parameter in predicting severe myocarditis. RESULTS: Among the 73 patients with myocarditis, 20 (27.4%) patients had severe myocarditis. Compared with mild myocarditis group, sinus tachycardia (p = 0.001), QRS duration ≥110 ms (p = 0.001), prolonged QTc interval (p < 0.001), and bundle branch block (p = 0.007) at the time of myocarditis were more common in the severe myocarditis group. Logistic regression analysis revealed that sinus tachycardia (p = 0.028) and QTc interval prolongation (p = 0.007) were predictors of severe myocarditis. Whereas the predictive value of other electrocardiographic parameters was weak. Concurrent targeted therapy didn't increase the risk of severe myocarditis. A high NT-proBNP level was associated with severe myocarditis. CONCLUSIONS: ECG at the onset of myocarditis manifested as sinus tachycardia and prolonged QTc interval predicted a high risk of severe myocarditis. Early detection of ECG abnormalities may faciliate early detection of severe ICI-associated myocarditis.

Clofazimine serum concentration and safety/efficacy in nontuberculous mycobacterial pulmonary disease treatment.

BACKGROUND: Clofazimine (CFZ) has shown promising effects against Mycobacterium avium-intracellulare complex pulmonary disease (MAC-PD) and Mycobacterium abscessus species pulmonary disease (MABS-PD). However, the optimal CFZ dose remains unknown. We aimed to explore the relationship between steady-state CFZ concentration and its safety and efficacy in MAC-PD and MABS-PD. METHODS: This prospective observational study focused on patients with MAC-PD and MABS-PD treated with CFZ (UMIN 000041053). To understand the safety and efficacy profile of CFZ and elucidate its optimal concentration, we analyzed CFZ-induced pigmentation grade, QTc interval, and culture conversion outcomes in relation to serum CFZ concentration using Student's t-test, a concentration-QTc model, and multivariable logistic regression analysis, respectively. In total, 64 patients (34 with MAC-PD; 30 with MABS-PD) were included. RESULTS: The steady-state concentration of CFZ was higher in the moderate-to-severe pigmentation group than in the none-to-light pigmentation group (P < 0.001). At a CFZ concentration of 1 mg/L, the QTc interval was prolonged by 17.3 ms (95 % confidence interval [CI], 3.9-25.4) from baseline. Culture conversion was achieved in 33 (51.6 %) patients. The only significant predictor of culture conversion was surgery (adjusted odds ratio, 5.4; 95 % CI, 1.3-38.0). CFZ concentration and MIC of CFZ less than 0.25 mg/L were not associated with culture conversion in this study. CONCLUSION: CFZ-induced pigmentation and QT interval prolongation are associated with serum CFZ concentrations. CFZ dosage may be optimized by monitoring serum CFZ concentration.

QTc interval changes among patients on psychotropic medications: A prospective observational study.

Background: Psychotropic medications are commonly prescribed for the treatment of psychiatric disorders. Various studies have reported QT interval (QTc) prolongation with the use of psychotropics. However, some studies have found no significant risk of QTc changes with these medications. Aim: To assess the effect of psychotropics on QTc in drug-naive psychiatric patients. Materials and Methods: Our study was a prospective observational study, conducted at a tertiary care hospital. Patients aged 18-45 years, drug-naïve, with no medical comorbidity or substance use history, were recruited for the study. ECG to assess QTc was recorded at baseline, second and fourth week after the starting of psychotropic medications. Results: N=8 (4%) patients had QTc prolongation at baseline and were excluded. No clinically significant QTc prolongation was noticed, after 2 weeks and 4 weeks of treatment with any of the psychotropic medications. However, among patients on escitalopram, a significant effect on QTc was noted (P = 0.001) as compared to those on sertraline, risperidone, and olanzapine (P > 0.05). Conclusion: The short-term risk of QTc prolongation with the use of newer psychotropics at optimal doses appears low among young patients with normal baseline QTc and no significant medical or substance use comorbidity.

Determining QTc in acute care settings: What we (don't) know.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.