Prevention of torsade de pointes in hospital settings: a scientific statement from the American Heart Association and the American College of Cardiology Foundation

Psychotropic Polypharmacy and QT Prolonging Medications in Hospitalized Patients

It is common for patients with mental illnesses to be prescribed multiple psychotropic medications to effectively manage their conditions. Psychotropic polypharmacy has been shown to potentiate and increase the risks of several adverse effects, including QT prolongation. This study aimed to investigate the prescribing trends of and differences in prescribing of QT-prolonging medications (QTPMs) at admission and discharge in hospitalized patients. This retrospective observational study utilized inpatient data from three public hospitals between January and December 2019. QTPMs were classified according to the AZCERT classification. QTPMs doses were evaluated by calculating the ratio of prescribed daily dose (PDD) to the defined daily dose (DDD). Subgroup analyses showed significant differences between patient groups on admission and discharge (all p < 0.001). Mean QTPMs decreased significantly between the two time points only in patients admitted to acute medical and geriatric units (p < 0.001). PDD/DDD ratio for conditional risk QTPMs in acute mental health unit (AMHU) patients was increased at discharge (p = 0.038). Patients admitted to acute medical and geriatric units were four and eight times more likely to be discharged with one QTPM with known risk in combination with more QTPMs with conditional risk. Logistic regression showed significant relationships with age and total number of regular medicines at admission for those prescribed high-dose QTPMs at discharge. The findings underscore the necessity for enhanced monitoring of QTPMs in hospitalized patients, particularly for those at higher risk.

Loperamide-induced severe cardiotoxicity: a toxicokinetic and toxicodynamic analysis derived from a case series and the published literature

INTRODUCTION

Chronic loperamide overdose is associated with cardiotoxicity. We describe the toxicokinetics of loperamide and N-desmethyl loperamide, and their concentration-response relationship on cardiotoxicity in newly described and published cases.

MATERIALS AND METHODS

We obtained serial loperamide and N-desmethyl loperamide concentrations, and corresponding electrocardiographic intervals in three episodes (two patients) of loperamide-related cardiotoxicity. A toxicokinetic and toxicodynamic analysis was undertaken that included data from previous publications to explore the relationship between these variables.

RESULTS

Patients presented with dizziness, bradycardia, loss of consciousness, and jerking or ventricular tachycardia after taking loperamide 320-400 mg/day for weeks or years. In one patient, ventricular tachycardia occurred on days two and three post-admission. Prolonged electrocardiographic intervals resolved after approximately five days. Admission loperamide concentrations were 5.37-288 μg/L and the terminal elimination half-lives were 21.3-38.7 h. Admission N-desmethyl loperamide concentrations were 87.67-256.34 μg/L and the terminal elimination half-life was 31.9-88.9 h. Overall, there were 42 loperamide and 35 N-desmethyl loperamide concentrations with paired electrocardiographic data, and the concentration-response relationship was derived using a maximum effect (Emax) model. Lower loperamide concentrations were associated with electrocardiographic abnormalities, compared to N-desmethyl loperamide concentrations. The total relative loperamide concentration, which combines both concentrations into a single value using in vitro inhibitory potencies at cardiac ion channels, out-performed either parent or metabolite concentrations alone for predicting cardiotoxicity on receiver operating characteristic curves.

DISCUSSION

Loperamide and N-desmethyl loperamide have long elimination half-lives causing prolonged cardiotoxicity. Higher loperamide and N-desmethyl loperamide concentrations are associated with prolonged electrocardiographic intervals.

CONCLUSIONS

Patients with chronic loperamide overdose are at risk of cardiotoxicity that persists for days due to persistent loperamide and N-desmethyl loperamide concentrations. We believe patients with loperamide overdose need an admission electrocardiograph and continuous monitoring until electrocardiographic changes resolve.

Risk Factors Associated with Unsuccessful Dofetilide Initiation Due to Excessive QT Interval Prolongation: A Retrospective Study

Dofetilide is a class III anti-arrhythmic medication approved for patients with atrial fibrillation to maintain sinus rhythm. Excessive QTc interval prolongation, a potential side effect of dofetilide, increases the risk of torsades de pointes. This risk is mitigated by closely monitoring the QTc interval during an inpatient initiation protocol for the first five doses. Prior studies have demonstrated that dofetilide can be safely used in patients with heart failure after completing the initiation protocol. However, no studies have investigated risk factors associated with dofetilide-induced excessive QTc interval prolongation, resulting in discontinuation of the medicine. This single-center retrospective cohort study analyzed the association between dofetilide-associated excessive QTc prolongation during medication initiation and pertinent medical comorbidities as well as various echocardiographic values of interest. Risk factors found to be significantly associated with excessive QTc prolongation during dofetilide initiation included a clinical history of heart failure, reduced left ventricular ejection fraction, increased left ventricular end-diastolic diameter, increased left atrial diameter, and reduced right ventricular systolic function. Although some studies have demonstrated the safety of dofetilide use in patients with heart failure, our findings suggest that these patients are less likely to tolerate initiation of the medication due to excessive QTc prolongation.

Cardiovascular toxicity of anaplastic lymphoma kinase inhibitors for patients with non-small cell lung cancer: a network meta-analysis

Aim: We conducted network meta-analysis to assess cardiovascular toxicity of anaplastic lymphoma kinase-tyrosine kinase inhibitors (ALK-TKIs).Materials & methods: Eleven articles involving 2855 patients and six interventions including crizotinib, alectinib, ceritinib, lorlatinib, brigatinib and chemotherapy were analyzed.Results: No significant difference was observed in overall cardiovascular risk among ALK-TKIs. Subgroup analysis showed that for cardiac toxicity, crizotinib and alectinib were more likely to cause myocardial rhythm abnormalities. Crizotinib and ceritinib had a higher risk of Q-T prolongation than chemotherapy. For vascular toxicity, crizotinib and ceritinib had a higher risk of thrombotic events than brigatinib. Crizotinib and lorlatinib were more likely to cause blood pressure abnormalities.Conclusion: Clinicians should carefully monitoring cardiovascular events when ALK-TKIs used in NSCLCs patients with baseline cardiovascular diseases.

Advanced QT interval analysis in long-term electrocardiography using shape-based clustering and template matching: A novel approach for Holter monitoring

Introduction

The QT interval, a critical parameter in electrocardiography (ECG), is challenging to analyze accurately because of variations in T-wave morphology, especially in long-term ECG recordings, such as Holter monitoring. Current methods, which are often manual or semi-automated, lack consistency and efficiency, underscoring the need for a more reliable and automated approach.

Methods

We developed a novel QT interval analysis algorithm that integrates K-shape clustering with Dynamic Time Warping under Limited Warping Path Length for template matching. This method automatically categorizes ECG waveforms into clusters based on shape similarity, and then selects representative template waveforms for each cluster. This approach aimed to standardize and automate the process of identifying and analyzing QT intervals across varying waveform patterns.

Results

Validation of the algorithm using the QT Database, which encompasses a broad spectrum of ECG waveform patterns, confirmed its ability to accurately identify and analyze the QT interval across diverse T-wave morphologies, in close agreement with expert human analysis. The reliability of the algorithm was quantified using the Intraclass Correlation Coefficient. For the QT interval, the Intraclass Correlation Coefficient (2,1) was 0.9 [95 % CI: 0.89, 0.91], and for the QTcB interval, it was 0.82 [95 % CI: 0.80, 0.84], both reflecting high reliability. The reliability of the algorithm was also evaluated by comparing it with DSC5500 from Nihon Kohden analysis program for long-time ECGs, a commercial software program that uses the tangential method. For the QT interval calculated by the developed algorithm, the Intraclass Correlation Coefficient (2,1) was 0.95 [95 % CI: 0.92, 0.97], and for the QT interval calculated by the DSC 5500, it was 0.70 [95 % CI: 0.54, 0.81]. For all waves, the mean and standard deviation of the difference between the algorithm and the expert analysis was 0.5 (±16), and that of the difference between the DSC5500 and the expert analysis was -16.4 (±42.8). For biphasic T-wave, the mean and standard deviation of the difference between the algorithm and the expert analysis was -0.3 (±15.9), and that of the difference between the DSC5500 and the expert analysis was -79.3 (±60.6). The results showed that the developed algorithm performed better than the DSC5500 for all shapes, especially for biphasic T-wave. The algorithm also demonstrated enhanced time efficiency and streamlined QT interval analysis in clinical settings.

Discussion

The new algorithm enhanced automated QT interval analysis, especially for long-term ECG recordings. Its effectiveness in processing different T-wave morphologies with accuracy and efficiency makes it a promising tool for clinical use and improving QT interval analysis in patient care and diagnostics.

Computerized QT and QTc Measurements From Bedside ICU Monitors Are Similar to Those Derived From a Standard 12-Lead ECG

QT/QTc prolongation is associated with an increased risk for torsade de pointes. In at-risk hospitalized patients, it is common to obtain a standard 12-lead electrocardiogram (ECG) for this assessment, but this interrupts patient care. Our hospital recently introduced bedside monitors in the intensive care unit (ICU) with continuous QT/QTc software. However, only four of the seven available ECG leads are used.

PURPOSE

Evaluate the agreement between computerized QT/QTc measurements from the bedside monitor (four leads) and a time-matched standard 12-lead ECG.

DESIGN

Prospective observational study in three adult ICUs.

METHODS

QT/QTc measurements were obtained from a convenience sample, and the two ECG types were ≤ 30 min apart. Agreement was evaluated using Bland-Altman analysis.

RESULTS

A total of 120 patients were evaluated for inclusion, and 60 (50%) had a 12-lead ECG for comparison. The mean bias difference for QT measurements was not statistically different (β = -2.47, 95% CI = 5.50 to -11.05; p = 0.44; limits of agreement (LOA) = -64.37 to 59.44). Similar non-statistical differences were observed for QTc (β = -3.20, 95% CI = 5.50 to -11.05; p = 0.44; LOA = -67.43 to 61.03).

CONCLUSION

There was good agreement for both QT and QTc measurements between the two methods. These pilot data are promising and suggest QT/QTc measurements from bedside monitors (four leads) may be an acceptable alternative to obtaining additional standard 12-lead ECGs. Given that half of the ICU patients screened did not have a 12-lead ECG recorded, bedside monitor QT/QTc's could identify at-risk patients. However, an evaluation in a larger sample and non-ICU patients is warranted.

Evaluation of ventricular repolarization in dermatomyositis and relationship with inflammation and autoimmunity

Dermatomyositis (DM) is a chronic multi-systemic inflammatory disorder of autoimmune origin, which has been associated with cardiovascular complications, including ventricular arrhythmias and sudden cardiac death. The Tp-e interval and Tp-e/QT ratio have been accepted as new markers for the assessment of myocardial repolarization and ventricular arrhythmogenesis. The aim of this study was to evaluate ventricular repolarization by using Tp-e interval and Tp-e/QT ratio in patients with DM, and to assess the relation with inflammation and autoimmunity. This study included 281 DM patients (180 females, 101 males; mean age 52.73 ± 15.80 years) and 281 control subjects (180 females, 101 males; mean age 53.38 ± 15.72 years). QTc, Tp-e interval and Tp-e/QT ratio were measured from the 12-lead ECG. The plasma level of blood routine test, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR) was measured. These parameters were compared between groups. No statistically significant difference was found between two groups in terms of basic characteristics. In electrocardiographic parameters analysis, QTc, Tp-e interval and Tp-e/QT ratio were significantly increased in DM patients compared to the control group (441.44 ± 26.62 ms vs 422.72 ± 11.7 ms, 104.16 ± 24.34 ms vs 77.23 ± 16.25 ms and 0.27 ± 0.06 ms vs 0.20 ± 0.04 ms, all P value < 0.01). QTc, Tp-e interval and Tp-e/QT were positively correlated with NLR, CRP, and ESR (all P values < 0.01), and were increased in anti-Ro/SSA-52kD positive patients compared to those negative (452.33 ± 24.89 ms vs 438.55 ± 26.37 ms, 114.05 ± 22.68 ms vs 101.53 ± 24.13 ms, and 0.29 ± 0.06 ms vs 0.27 ± 0.05 ms, all P value < 0.01). Our study demonstrated that QTc, Tp-e interval, and Tp-e/QT ratio were increased in DM patients and were associated with inflammatory markers and anti-Ro/SSA-52kD positivity.

QTc Interval: A frequently unrecognized electrocardiographic interval

The QT interval, an electrocardiographic temporal representation of the ventricular depolarization and repolarization, is an integral parameter that must be carefully evaluated to gather critical information regarding electrical instability that may cause malignant ventricular dysrhythmias or sudden cardiac death. The QT interval is affected by several inheritable and acquired factors, such as genetic mutations, electrolyte disturbances, and medication interactions. We strongly believe that prompt and accurate recognition of any QT interval abnormalities is critical in many clinical settings. This concise review article highlights the importance of accurate measurement of the QT interval, enhances understanding of the most prevalent factors yielding abnormalities within the QT interval and the prognostic value of the QT interval, as well as provides several key practical reminders for healthcare professionals to strengthen our clinical practice.

Intraoperative QTc interval interpretation: Effects of anaesthesia, ECG, correction formulae, sex, and current limits: A Prospective Observational Study

BACKGROUND

Severe QT interval prolongation requires monitoring QTc intervals during anaesthesia with recommended therapeutic interventions at a threshold of 500 ms. The need for 12-lead ECG and lack of standardisation limit such monitoring. We determined whether automated continuous intraoperative QTc monitoring with 5-lead ECG measures QTc intervals comparable to 12-lead ECG and whether the interpretation of QTc intervals depends on the correction formulae and the patient's sex. We compared intraoperative QTc times to QTc times from resting ECGs of a population from the same region, to substantiate the hypothesis that patients under general anaesthesia may need specific treatment thresholds.

METHODS

In this prospective observational study, intraoperative QT/QTc intervals were automatically recorded using 12 and 5-lead ECG in 100 patients (44% males). QTc values were analysed for sex and formula-specific aspects after correction for heart rate according to Bazett, Fridericia, Hodges, Framingham, Charbit and QTcRAS, and compared to a regional community-based cohort. The level of significance was set to α = 0.05.

RESULTS

QT interval duration was not significantly different between 12-lead and 5-lead ECG (difference - 0.09 ms ± 8.5 ms, p = 0.793). The QTc interval duration significantly differed between the correction formulae (p < 0.001) and between sexes (p < 0.001). Mean intraoperative QTc duration was higher than in resting ECGs from a large community-based population with the same regional background (438 vs. 417 ms). The incidence of prolonged values >500 ms significantly depended on the correction formula (p < 0.001) and was up to tenfold higher in women versus men.

CONCLUSION

Intraoperative QTc interval measurement using a 5-lead ECG is valid. Correction formulae and gender influence the intraoperative QTc interval duration and the incidence of pathologically prolonged values according to current limits. The consideration and definition of sex-specific normal limits for QTc times under general anaesthesia, therefore, warrant further investigation.

Assessing the Risk of QT Prolongation in a Psychiatric Inpatient Cohort: A Retrospective Cross-Sectional Study

BACKGROUND

QT prolongation is a potential serious adverse drug reaction, and assessing the risk of QT-prolonging drugs is routinely included in psychotropic medication reviews. However, the actual clinical benefits of such assessments are unknown. We investigate whether QT prolongation (QTc value > 480 ms) manifests in psychiatric inpatients at risk of QT prolongation as identified by assessing drug regimens. Secondly, we test the predictive value of well-known risk factors for QT prolongation.

RESULTS

The median patient age was 49 years (IQR 34-64) for patients treated with a median of nine drugs (IQR 6-12) and a median QT-prolonging drug sum of three daily defined dosages (IQR 1.88-4.76). We extracted 290 ECGs for patients where pharmacist-led-medication reviews (PMRs) identified an increased risk of QT prolongation and 190 ECGs for patients with no such risk, identifying 33 cases of verified QT prolongation equally distributed between groups. Unadjusted regression analysis revealed that advanced age (OR 3.27 CI 95% 1.60-6.84) and cardiovascular comorbidity (OR 3.53 CI 95% 1.71-7.29) were associated with manifest QT prolongation, while the QT-prolonging drug load was not.

METHODS

We reviewed electronic health records (EHRs) of 799 psychiatric inpatients exposed to PMRs made from 1 September 2016 to 31 December 2018 in Region Zealand Denmark.

CONCLUSIONS

Patients at risk of QT prolongation as identified by drug reviews rarely manifests with actual QT prolongation. Non-pharmacological risk factors seem to be better predictors for identifying patients with QT prolongation.

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.

Association of anxiolytic drugs with Torsade de Pointes: a pharmacovigilance study of the Food and Drug Administration Adverse Event Reporting System

Background

This study aimed to determine the association of Torsade de Pointes (TdP) with anxiolytic drugs and present a detailed overview of anxiolytic-induced cases of TdP reported to the Food and Drug Administration Adverse Event Reporting System (FAERS).

Methods

All cases of anxiolytic-induced TdP (n = 260) between 1990 and 2020 were retrieved from the FAERS database using the Preferred Term 'Torsade de Pointes, code: 10044066' from the Medical Dictionary for Regulatory Activities (MedDRA version 22). Four data-mining algorithms were used for disproportionality analysis: Reporting Odds Ratio (ROR), Proportional Reporting Ratio (PRR), Empirical Bayes Geometric Mean (EBGM), and Information Content (IC). Anxiolytics with ≥3 TdP cases were included.

Results

Of a total of eight drugs, this study identified seven signals of TdP, of which six signals were new, namely for alprazolam, bromazepam, lorazepam, meprobamate, midazolam, and oxazepam. Based on disproportionality analysis, among new signals, the highest risk of TdP was observed with bromazepam and midazolam. Alprazolam showed the lowest risk for TdP, while diazepam did not reach significant disproportionality.

Conclusions

This study identified six new signals of TdP among anxiolytic drugs, so warranting stringent clinical studies to ascertain the actual risk of TdP and ensure patient safety.

Clinical Trial Registration

This study is registered at ClinicalTrials.gov (NCT.gov ID: NCT04293432).

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.

Obesity Arrhythmias: Role of IL-6 Trans-Signaling

Obesity is a chronic disease that is rapidly increasing in prevalence and affects more than 600 million adults worldwide, and this figure is estimated to increase by at least double by 2030. In the United States, more than one-third of the adult population is either overweight or obese. The global obesity epidemic is a major risk factor for the development of life-threatening arrhythmias occurring in patients with long QT, particularly in conditions where multiple heart-rate-corrected QT-interval-prolonging mechanisms are simultaneously present. In obesity, excess dietary fat in adipose tissue stimulates the release of immunomodulatory cytokines such as interleukin (IL)-6, leading to a state of chronic inflammation in patients. Over the last decade, increasing evidence has been found to support IL-6 signaling as a powerful predictor of the severity of heart diseases and increased risk for ventricular arrhythmias. IL-6's pro-inflammatory effects are mediated via trans-signaling and may represent a novel arrhythmogenic risk factor in obese hearts. The first selective inhibitor of IL-6 trans-signaling, olamkicept, has shown encouraging results in phase II clinical studies for inflammatory bowel disease. Nevertheless, the connection between IL-6 trans-signaling and obesity-linked ventricular arrhythmias remains unexplored. Therefore, understanding how IL-6 trans-signaling elicits a cellular pro-arrhythmic phenotype and its use as an anti-arrhythmic target in a model of obesity remain unmet clinical needs.

Proarrhythmic major adverse cardiac events with donepezil: A systematic review with meta-analysis

BACKGROUND

Cholinesterase inhibitors (ChEIs) are regularly used in Alzheimer's disease. Of the three ChEIs approved for dementia, donepezil is among the most prescribed drugs in the United States with nearly 6 million prescriptions in 2020; however, it is classified as a "known risk" QT interval-prolonging medication (QTPmed). Given this claim is derived from observational data including single case reports, we aimed to evaluate high-quality literature on the frequency and nature of proarrhythmic major adverse cardiac events (MACE) associated with donepezil.

METHODS

We searched Medline, Embase, International Pharmaceutical Abstracts, and Cochrane Central from 1996 onwards for randomized controlled trials (RCTs) involving patients age ≥18 years comparing donepezil to placebo. The MACE composite included mortality, sudden cardiac death, non-fatal cardiac arrest, Torsades de pointes, ventricular tachyarrhythmia, seizure or syncope. Random-effects meta-analyses were performed with a treatment-arm continuity correction for single and double zero event studies.

RESULTS

Sixty RCTs (n = 12,463) were included. Twenty-five of 60 trials (n = 5886) investigated participants with Alzheimer's disease and 33 trials monitored electrocardiogram data. The mean follow-up duration was 31 weeks (SD = 36). Mortality was the most commonly reported MACE (252/331, 75.8% events), the remainder were syncope or seizures, with no arrhythmia events. There was no increased risk of MACE with exposure to donepezil compared to placebo (risk ratio [RR] 1.08, 95% CI 0.88-1.33, I2 = 0%) and this was consistent in the subgroup analysis of trials including participants with cardiovascular morbidities (RR 1.14, 95% CI 0.88-1.47). Subgroup analysis suggested a trend toward more events with donepezil with follow-up ≥52 weeks (RR: 1.32, 0.98-1.79).

CONCLUSIONS

This systematic review with meta-analysis found donepezil may not be arrhythmogenic. Donepezil was not associated with mortality, ventricular arrhythmias, seizure or syncope, although longer durations of therapy need more study. Further research to clarify actual clinical outcomes related to QTPmed is important to inform prescribing practices.

Prevalence of prolonged QTc interval among HIV infected patients on highly active antiretroviral therapy (HAART) and its relationship with CD4 cells count and viral load at a tertiary hospital in North Eastern Nigeria

Background

Patients living with HIV infection remain at increased risk of cardiovascular diseases and sudden cardiac death. Various prevalence of electrocardiographic (ECG) abnormalities among HIV-infected patients were reported: Attamah et al reported the prevalence of electrocardiographic abnormalities among HIV-infected patients as 34.5%, while Orunta et al reported a prevalence of 42.9%, and Njoku et al reported a prevalence of 93.0%. Human immunodeficiency virus-infected patients are at increased risk of developing prolonged QT interval. Sani et al reported the prevalence of prolonged corrected QT interval among HIV-infected patients as 45.0%. Innocent et al reported a prevalence of48.0%, while Ajala et al reported a prevalence of 18%. Prolonged QTc interval increases the risk of premature ventricular contraction which can degenerate into ventricular tachycardia and or ventricular that can result in sudden cardiac death.

Methodology

The study was a cross-sectional conducted among HIV-infected patients receiving HAART at the Federal Medical Centre Nguru, Yobe State, North Eastern Nigeria.

Results

One hundred and seven (107) subjects were recruited into the study comprising thirty-three (37.0%) males and 70(65.4%) females. The mean CD4 cell count, and viral load of the studied patients were 612.64±34.75 cells/μL and4646.30±58.68 copies/mL respectively. Twenty (18.7%) patients had prolonged QTc interval, this gave us the prevalence of prolonged QTc in this study as 18.7%. The commonest cardiac rhythm was sinus rhythm (69.2%), followed by sinus tachycardia (26.2%) and atrial fibrillation 5(4.7%). Other electrocardiographic findings include First-degree atrioventricular block was seen in seven (6.5%) patients, Premature ventricular contractions were found in16.8%, RBBB was observed in 2.8%, 3.7% of patients had LBBB and 4.7% had left posterior hemiblock. The distribution of QTc interval according to CD4 cells count and viral revealed a statistically significant difference across the groups. All the patients with prolonged QTc interval had lower CD4 cells count and higher viral load suggesting that HIV disease severity is associated with prolonged QTc interval.

Conclusion

In conclusion, the study revealed that the prevalence of prolonged QTc interval among HIV infected patients on highly active antiretroviral therapy was found to be 18.7%, and that HIV disease severity increases the risk of developing prolonged QTc interval.

QTc prolongation after aneurysmal subarachnoid hemorrhage might be associated with worse neurologic outcome in patients receiving microsurgical clipping or embolization of the intracranial aneurysms: a retrospective observational study

PURPOSE

QT interval prolongation is one of the most common electrocardiographic (ECG) abnormalities in patients with aneurysmal subarachnoid hemorrhage (aSAH). Whether corrected QT interval (QTc) prolongation is associated with perioperative cardiac events and dismal neurological outcome in mid to long-term follow-up in patients after aSAH is insufficiently studied and remains controversial.

METHODS

We retrospectively studied the adult (≥ 18 years) patients admitted to our institution between Jan 2018 and Dec 2020 for aSAH who underwent intracranial aneurysm clipping or embolization. The patients were divided into 2 groups (normal and QTc prolongation groups) according to their QTc. To minimize the confounding bias, a propensity score matching (PSM) analysis was performed to compare the neurologic outcomes between patients with normal QTc and QTc prolongation.

RESULTS

After screening, 908 patients were finally included. The patients were divided into 2 groups: normal QTc groups (n = 714) and long QTc group (n = 194). Female sex, hypokalemia, posterior circulation aneurysm, and higher Hunt-Hess grade were associated with QTc prolongation. In multiple regression analysis, older age, higher hemoglobin level, posterior circulation aneurysm, and higher Hunt-Hess grade were identified to be associated with worse outcome during 1-year follow-up. Before PSM, patients with QTc prolongation had higher rate of perioperative cardiac arrest or ventricular arrhythmias. After PSM, there was no statistical difference between normal and QTc prolongation groups in perioperative cardiac events. However, patients in the QTc prolongation group still had worse neurologic outcome during 1-year follow-up.

CONCLUSIONS

QTc prolongation is associated with worse outcome in patients following SAH, which is independent of perioperative cardiac events.

QTNet: Predicting Drug-Induced QT Prolongation With Artificial Intelligence-Enabled Electrocardiograms

BACKGROUND

Prediction of drug-induced long QT syndrome (diLQTS) is of critical importance given its association with torsades de pointes. There is no reliable method for the outpatient prediction of diLQTS.

OBJECTIVES

This study sought to evaluate the use of a convolutional neural network (CNN) applied to electrocardiograms (ECGs) to predict diLQTS in an outpatient population.

METHODS

We identified all adult outpatients newly prescribed a QT-prolonging medication between January 1, 2003, and March 31, 2022, who had a 12-lead sinus ECG in the preceding 6 months. Using risk factor data and the ECG signal as inputs, the CNN QTNet was implemented in TensorFlow to predict diLQTS.

RESULTS

Models were evaluated in a held-out test dataset of 44,386 patients (57% female) with a median age of 62 years. Compared with 3 other models relying on risk factors or ECG signal or baseline QTc alone, QTNet achieved the best (P < 0.001) performance with a mean area under the curve of 0.802 (95% CI: 0.786-0.818). In a survival analysis, QTNet also had the highest inverse probability of censorship-weighted area under the receiver-operating characteristic curve at day 2 (0.875; 95% CI: 0.848-0.904) and up to 6 months. In a subgroup analysis, QTNet performed best among males and patients ≤50 years or with baseline QTc <450 ms. In an external validation cohort of solely suburban outpatient practices, QTNet similarly maintained the highest predictive performance.

CONCLUSIONS

An ECG-based CNN can accurately predict diLQTS in the outpatient setting while maintaining its predictive performance over time. In the outpatient setting, our model could identify higher-risk individuals who would benefit from closer monitoring.

Evaluating the prescribing and monitoring of medications associated with QTc-prolongation in the ambulatory care setting

RATIONALE

Little is known about the prescribing of medications with potential to cause QTc-prolongation in the ambulatory care settings. Understanding real-world prescribing of QTc-prolonging medications and actions taken to mitigate this risk will help guide strategies to optimize safety and appropriate prescribing among ambulatory patients.

OBJECTIVE

To evaluate the frequency of clinician action taken to monitor and mitigate modifiable risk factors for QTc-prolongation when indicated.

METHODS

This retrospective, cross-sectional study evaluated clinician action at the time of prescribing prespecified medications with potential to prolong QTc in adult patients in primary care. The index date was defined as the date the medication was ordered. Electronic health record (EHR) data were evaluated to assess patient, clinician and visit characteristics. Clinician action was determined if baseline or follow-up monitoring was ordered or if action was taken to mitigate modifiable risk factors (laboratory abnormalities or electrocardiogram [ECG] monitoring) within 48 h of prescribing a medication with QTc-prolonging risk. Descriptive statistics were used to describe current practice.

RESULTS

A total of 399 prescriptions were prescribed to 386 patients, with a mean age of 51 ± 18 years, during March 2021 from a single-centre, multisite health system. Of these, 17 (4%) patients had a known history of QTc-prolongation, 170 (44%) did not have a documented history of QTc-prolongation and 199 (52%) had an unknown history (no ECG documented). Thirty-nine patients (10%) had at least one laboratory-related risk factor at the time of prescribing, specifically hypokalemia (16 patients), hypomagnesemia (8 patients) or hypocalcemia (19 patients). Of these 39 patients with laboratory risk factors, only 6 patients (15%) had their risk acknowledged or addressed by a clinician. Additionally, eight patients' most recent QTc was ≥500 ms and none had an ECG checked at the time the prescription was ordered.

CONCLUSION

Despite national recommendations, medication monitoring and risk mitigation is infrequent when prescribing QTc-prolonging medications in the ambulatory care setting. These findings call for additional research to better understand this gap, including reasons for the gap and consequences on patient outcomes.

Predictors for prolonged qt intervals in acute antipsychotic poisoned patients

Background

Acute antipsychotic poisoning is correlated to a high prevalence of qt interval prolongation.

Aim

This study aimed to evaluate early qt interval prolongation predictors in acute antipsychotic-poisoned patients.

Methodology

This prospective cohort study enrolled 70 symptomatic patients with acute antipsychotic poisoning. Sociodemographic data, toxicological, clinical, investigation, and outcomes were collected and analyzed. The estimation of the corrected qt interval (QTc) was performed using Bazett's method. Primary outcome was normal or abnormal length of QTc interval. Secondary outcomes included duration of hospital stay, complete recovery and mortality. The corrected qt interval was analyzed by univariate and multivariate logistic regression analysis.

Results

Patients were divided into groups A (normal QTc interval up to 440 msec; 58.6% of cases) and B (prolonged QTc interval ≥ 440 msec; 41.4% of cases). Patients in group B had significantly high incidences of quetiapine intake, bradycardia, hypotension, hypokalemia, and long duration of hospital stay. By multivariate analysis, quetiapine [Odd's ratio (OR): 39.674; Confidence Interval (C.I:3.426-459.476)], bradycardia [OR: 22.664; C.I (2.534-202.690)], and hypotension [OR: 16.263; (C.I: 2.168-122.009)] were significantly correlated with prolonged QTc interval.

Conclusion

In acute antipsychotic poisoning, quetiapine, bradycardia, and hypotension are early clinical predictors for prolonged QTc interval.

Mechanisms of torsades de pointes: an update

Torsades de Pointes (TdP) refers to a polymorphic ventricular tachycardia (VT) with undulating QRS axis that occurs in long QT syndrome (LQTS), although the term has been used to describe polymorphic ventricular tachyarrhythmias in which QT intervals are not prolonged, such as short-coupled variant of TdP currently known as short-coupled ventricular fibrillation (VF) and Brugada syndrome. Extensive works on LQTS-related TdP over more than 50 years since it was first recognized by Dessertennes who coined the French term meaning "twisting of the points", have led to current understanding of the electrophysiological mechanism that TdP is initiated by triggered activity due to early afterdepolarization (EAD) and maintained by reentry within a substrate of inhomogeneous repolarization. While a recently emerging notion that steep voltage gradients rather than EADs are crucial to generate premature ventricular contractions provides additions to the initiation mode, the research to elucidate the maintenance mechanism hasn't made much progress. The reentrant activity that produces the specific form of VT is not well characterized. We have conducted optical mapping in a rabbit model of electrical storm by electrical remodeling (QT prolongation) due to chronic complete atrioventricular block and demonstrated that a tissue-island with prolonged refractoriness due to enhanced late Na+ current (INa-L) contributes to the generation of drifting rotors in a unique manner, which may explain the ECG characteristic of TdP. Moreover, we have proposed that the neural Na+ channel NaV1.8-mediated INa-L may be a new player to form the substrate for TdP. Here we discuss TdP mechanisms by comparing the findings in electrical storm rabbits with recently published studies by others in simulation models and human and animal models of LQTS.

Novel application of convolutional neural networks for artificial intelligence-enabled modified moving average analysis of P-, R-, and T-wave alternans for detection of risk for atrial and ventricular arrhythmias

BACKGROUND

T-wave alternans (TWA) analysis was shown in >14,000 individuals studied worldwide over the past two decades to be a useful tool to assess risk for cardiovascular mortality and sudden arrhythmic death. TWA analysis by the modified moving average (MMA) method is FDA-cleared and CMS-reimbursed (CAG-00293R2).

OBJECTIVE

Because the MMA technique is inherently suitable for dynamic tracking of alternans levels, it was selected for development of artificial intelligence (AI)-enabled algorithms using convolutional neural networks (CNN) to achieve rapid, efficient, and accurate assessment of P-wave alternans (PWA), R-wave alternans (RWA), and TWA.

METHODS

The novel application of CNN algorithms to enhance MMA analysis generated efficient and powerful pattern-recognition algorithms for highly accurate alternans quantification. Algorithm reliability and accuracy were verified using simulated ECGs achieving R2 ≥ 0.99 (p < 0.01) in response to noise inputs and artifacts that emulate real-life conditions.

RESULTS

Accuracy of the new AI-MMA algorithms in TWA analysis (n = 5) was significantly improved over unsupervised, automated MMA output (p = 0.036) and did not differ from conventional MMA analysis with expert overreading (p = 0.21). Accuracy of AI-MMA in PWA analysis (n = 45) was significantly improved over unsupervised, automated MMA output (p < 0.005) and did not differ from conventional MMA analysis with expert overreading (p = 0.89). TWA and PWA by AI-MMA were correlated with conventional MMA output over-read by an expert reader (R2 = 0.7765, R2 = 0.9504, respectively).

CONCLUSION

This novel technique for AI-MMA analysis could be suitable for use in diverse in-hospital and out-of-hospital monitoring systems, including cardiac implantable electronic devices and smartwatches, for tracking atrial and ventricular arrhythmia risk.

Incidences, risk factors, and clinical correlates of severe QT prolongation after the use of quetiapine or haloperidol

BACKGROUND

Case reports suggest that quetiapine or haloperidol use is associated with severe QT prolongation (SQTP) and torsades de pointes.

OBJECTIVE

The purpose of this study was to examine the incidences, risk factors, and outcomes of SQTP in quetiapine and haloperidol users.

METHODS

This study accessed electronic medical records from a multicenter health-care hospital system in Taiwan and included patients who received quetiapine or haloperidol therapy and had both baseline and follow-up electrocardiograms. SQTP was defined as a posttreatment corrected QT (QTc) interval exceeding 500 ms or an increase in QTc interval of >60 ms compared with the baseline value. We analyzed the risk factors and outcomes of SQTP using multivariate logistic regression.

RESULTS

Mean increases in QTc interval were +8.3 ± 51.8 and +8.9 ± 44.0 ms after the administration of quetiapine (n = 8832) and haloperidol (n = 2341). Among these users, 1149 (13.0%) and 333 (14.2%) developed SQTP, respectively. Common risk factors for SQTP included old age, heart failure, hypokalemia, amiodarone use, and baseline QTc interval. SQTP in quetiapine users was significantly associated with ventricular arrhythmias (odds ratio 2.84; 95% confidence interval 1.95-4.13) and sudden cardiac death (odds ratio 2.29; 95% confidence interval 1.44-3.66).

CONCLUSION

More than 10% of patients receiving quetiapine or haloperidol therapy developed SQTP, and many of them were exposed to risk factors for SQTP. SQTP in quetiapine users was significantly associated with increased risks of ventricular arrhythmias and sudden cardiac death. Clinicians should be vigilant for ventricular arrhythmias in quetiapine users who have risk factors for SQTP.

Characterization of cardiovascular profile of anti-influenza drug peramivir: A reverse-translational study using the isoflurane-anesthetized dog

An injectable anti-influenza drug peramivir has been reported to induce QT-interval prolongation in some phase III studies, although its thorough QT/QTc study was negative. We investigated the discrepancy among those clinical studies using isoflurane-anesthetized beagle dogs (n = 4). Peramivir in doses of 1 mg/kg/10 min (sub-therapeutic dose) followed by 10 mg/kg/10 min (clinically-relevant dose) was intravenously administered. Peramivir prolonged QT interval/QTcV and Tpeak-Tend, and tended to delay ventricular repolarization in a reverse-frequency dependent manner, indicating IKr inhibition in vivo. Meanwhile, peramivir did not alter P-wave duration, PR interval or QRS width, indicating a lack of impact on cardiac conduction via Na+ or Ca2+ channel inhibition in vivo. Peramivir prolonged Tpeak-Tend and tended to prolong terminal repolarization period, which would develop substrates for initiating and maintaining spiral reentry, respectively. Meanwhile, peramivir did not prolong J-Tpeakc, which could not induce early afterdepolarization, a trigger inducing torsade de pointes. Thus, our results support that clinical dose exposure of peramivir can delay the ventricular repolarization in influenza patients. Peramivir has only a small potential to induce torsade de pointes in patients with the intact hearts, but caution should be paid on its use for patients formerly having the trigger for torsade de pointes.

A quality improvement study of the implementation and initial results of a pragmatic clinical decision support system in the community pharmacy setting

BACKGROUND

A six year collaboration between academics, community pharmacists and informaticians, led to the development of nine guidelines for a clinical decision support system, enhancing community pharmacists' ability to address drug-related problems and improve care.

AIM

The objective of this study was to assess the effectiveness of clinical decision support system rules in enhancing medication management within the community pharmacy setting. This was achieved through retrospective monitoring of real-world usage and measuring the pharmacotherapeutic impact of the rules.

METHOD

In 2019, a retrospective observational evaluation appraised the acceptance rate of the clinical decision support system components in 490 Belgian pharmacies. Among these, 51 pharmacies underwent a longitudinal analysis involving (i) co-prescription of methotrexate and folic acid, (ii) gastroprotection with non-steroidal anti-inflammatory drugs, and (iii) drug combinations causing QT prolongation. The study period spanned one year pre-launch, one year post-launch, and two years post-launch.

RESULTS

Of the targeted pharmacies, 80% used 7 of the 9 rules. After four years, methotrexate-folic acid co-prescription increased 4%, reaching 79.8%. Gastroprotection improved by 3% among older patients and 7.47% in younger individuals (< 70 year) with multiple risk factors. The QT prolongation rules faced implementation difficulties.

CONCLUSION

Pharmacists' acceptance of the developed rules was high and coincided with a decline in drug-related problems, holding potential public health impact. This real-world data can inform the future implementation of such systems, as it demonstrated the need for more detailed data-gathering and more intensive training of pharmacists in the handling of more complex problems such as QT prolongation.

Genetic risk factors for drug-induced long QT syndrome: findings from a large real-world case-control study

Aim: Drug-induced long QT syndrome (diLQTS), an adverse effect of many drugs, can lead to sudden cardiac death. Candidate genetic variants in cardiac ion channels have been associated with diLQTS, but several limitations of previous studies hamper clinical utility. Materials & methods: Thus, the purpose of this study was to assess the associations of KCNE1-D85N, KCNE2-I57T and SCN5A-G615E with diLQTS in a large observational case-control study (6,083 self-reported white patients treated with 27 different high-risk QT-prolonging medications; 12.0% with diLQTS). Results: KCNE1-D85N significantly associated with diLQTS (adjusted odds ratio: 2.24 [95% CI: 1.35-3.58]; p = 0.001). Given low minor allele frequencies, the study had insufficient power to analyze KCNE2-I57T and SCN5A-G615E. Conclusion: KCNE1-D85N is a risk factor for diLQTS that should be considered in future clinical practice guidelines.

Prevalence of QT-Prolonging Drug-Drug Interactions in Psychiatry: A Systematic Review and Meta Analysis

Background: Drug-drug interactions (DDIs) are considered an emerging threat to the patients if undetected. DDIs can prolong QT interval, leading to fatal ventricular arrhythmia. Antipsychotics and antidepressants prescribed commonly to psychiatric patients have the propensity to prolong QT interval and can precipitate Torsades de pointes (TdP). This review aimed to summarize the prevalence of QT interval prolonging DDIs in psychiatric patients. Methods: This meta-analysis was carried out following the MOOSE (Meta-analysis of Observational Studies in Epidemiology) statement. Databases like Pubmed/MEDLINE, Google Scholar and Research gate were scanned for English language papers. Indexed terms from Medical Subject (MeSH) and other search terms for "QT prolongation", "Drug interactions", and "Psychiatry" were used to identify the articles. All published articles available until the day of the collection were considered. Outcome measures were analyzed with meta package in R language. Results: A total of 5 studies were eligible for inclusion. From the included studies, QT-prolonging DDIs were found in 14806 patients out of 30122 patients. The prevalence of QT-prolonging DDIs in psychiatric patients was found to be 42% (95% confidence interval: 21%, 66%). The factors associated with potential drug-drug interactions were related to patient characteristics such as polypharmacy, age and comorbid disease. Conclusion: This review concluded that psychiatric patients were prescribed the drugs/drug combinations which can prolong QT interval and can cause adverse effects on the cardiovascular system. Hence, it is important to implement precautionary safety interventions, be vigilant and prevent QT prolongation and adverse cardiac effects in clinical practice.

Complete Heart Block Induced Torsades de Pointes

High-degree atrioventricular node block is a known cause of bradycardia. Heart rate and QT interval have an inverse relation. Therefore, bradycardia can lead to prolonged QT interval, which can predispose patients to Torsades de Pointes, a life-threatening arrhythmia. Correcting the underlying etiology can often reverse the arrhythmia and prevent recurrence. For this reason, recognizing the etiology of this arrhythmia plays an essential role in management.

Repotrectinib in a Patient With NTRK Fusion-Positive Pancreatic Carcinoma and Congenital Long QT Syndrome

Repotrectinib in a patient with NTRK fusion-positive pancreatic carcinoma and congenital long QT syndrome.

Management of Arrhythmias in the Cardiovascular Intensive Care Unit

Arrhythmias in the cardiovascular intensive care unit (CVICU) can be difficult to manage because of the complex hemodynamic and respiratory states of critically ill patients. Treating physicians must be educated to prevent, diagnose, and treat a multitude of tachyarrhythmias and bradyarrhythmias. In this review article, the authors outline a pragmatic approach to patient assessment, arrhythmia diagnosis, and management of the most common arrhythmias seen in the CVICU.

Clinical and Laboratory Correlates of QTc Duration in Adult and Pediatric Sickle Cell Disease

Background

Sickle cell disease, a common genetic disorder in African Americans, manifests an increased risk of sudden death, the basis of which is incompletely understood. Prolongation of heart rate-corrected QT (QTc) interval on the electrocardiogram, a standard clinical measure of cardiac repolarization, may contribute to sudden death by predisposing to torsades de pointes ventricular tachycardia.

Methods

We established a cohort study of 293 adult and 121 pediatric sickle cell disease patients drawn from the same geographic region as the Jackson Heart Study (JHS) cohort, in which significant correlates of QT duration have been characterized and quantitatively modeled. Herein, we establish clinical and laboratory correlates of QTc duration in our cohort using stepwise multivariate linear regression analysis. We then compared our adult sickle cell disease data to effect-size predictions from the published JHS statistical model of QT interval duration.

Results

In adult sickle cell disease, gender, diuretic use, QRS duration, serum ALT levels, anion gap, and diastolic blood pressure show positive correlation; hemoglobin levels show inverse correlation; in pediatric sickle cell disease, age, hemoglobin levels, and serum bicarbonate and creatinine levels show inverse correlation. The mean QTc in our adult sickle cell disease cohort is 7.8 milliseconds longer than in the JHS cohort, even though the JHS statistical model predicts that the mean QTc in our cohort should be > 11 milliseconds shorter than in the much older JHS cohort, a differential of > 18 milliseconds.

Conclusion

Sickle cell disease patients have substantial QTc prolongation relative to their age, driven by factors some overlapping, in adult and pediatric sickle cell disease, and distinct from those that have been defined in the general African American community.

Navigating the pharmacologic complexities of QTc prolongation: assessing the cumulative burden in individuals with serious mental illness

The scientific progress made in the pharmacologic management of serious mental illness (SMI) has been significant. However, the benefits of medication management must continually be weighed against the risks of adverse effects of the agents prescribed. While many medications pose increased danger of QTc prolongation, which may result in malignant arrhythmia and sudden cardiac death, the combination of medications contributing QTc risk can result in an impact of unpredictable pharmacodynamic magnitude. Pharmacists play a key role in communicating QTc risks to prescribers, however little if any clinical guidance informs clinicians of specific actions to take when initiating or continuing a clinically necessary combination that poses risk. This study is a cross-sectional view of Med Safety Scan (MSS) QT prolongation risk scores, generated from the ranking tool available from the CredibleMeds website, intended to provide greater understanding of overall risk of QT burden to assist in the prescribing of medications to patients with SMI in a psychiatric hospital.

Corrected QT Interval (QTc) Diagnostic App for the Oncological Routine: Development Study

BACKGROUND

Numerous antineoplastic drugs such as chemotherapeutics have cardiotoxic side effects and can lead to long QT syndrome (LQTS). When diagnosed and treated in time, the potentially fatal outcomes of LQTS can be prevented. Therefore, regular electrocardiogram (ECG) assessments are critical to ensure patient safety. However, these assessments are associated with patient discomfort and require timely support of the attending oncologist by a cardiologist.

OBJECTIVE

This study aimed to examine whether this approach can be made more efficient and comfortable by a smartphone app (QTc Tracker), supporting single-lead ECG records on site and transferring to a tele-cardiologist for an immediate diagnosis.

METHODS

To evaluate the QTc Tracker, it was implemented in 54 cancer centers in Germany. In total, 266 corrected QT interval (QTc) diagnoses of 122 patients were recorded. Moreover, a questionnaire on routine ECG workflow, turnaround time, and satisfaction (1=best, 6=worst) was answered by the centers before and after the implementation of the QTc Tracker.

RESULTS

Compared to the routine ECG workflow, the QTc Tracker enabled a substantial turnaround time reduction of 98% (mean 2.67, 95% CI 1.72-2.67 h) and even further time efficiency in combination with a cardiologic on-call service (mean 12.10, 95% CI 5.67-18.67 min). Additionally, nurses and patients reported higher satisfaction when using the QTc Tracker. In particular, patients' satisfaction sharply improved from 2.59 (95% CI 2.41-2.88) for the routine ECG workflow to 1.25 (95% CI 0.99-1.51) for the QTc Tracker workflow.

CONCLUSIONS

These results reveal a significant improvement regarding reduced turnaround time and increased user satisfaction. Best patient care might be guaranteed as the exposure of patients with an uncontrolled risk of QTc prolongations can be avoided by using the fast and easy QTc Tracker. In particular, as regular side-effect monitoring, the QTc Tracker app promises more convenience for patients and their physicians. Finally, future studies are needed to empirically test the usability and validity of such mobile ECG assessment methods.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04055493; https://classic.clinicaltrials.gov/ct2/show/NCT04055493.

Increased ventricular ectopy precedes Torsades de Pointes in patients with prolonged QT

OBJECTIVE

Torsades de Pointes (TdP) is a potentially lethal ventricular tachydysrhythmia. Prolonged heartrate corrected QT interval (QTc) predicts TdP; however, with poor specificity. We performed this study to identify other predictors of TdP among patients with prolonged QTc.

METHODS

We performed a retrospective case control study with 2:1 matching at an urban academic hospital. We searched our hospital electrocardiogram (ECG) database for tracings with heartrate ≤ 60, QTc ≥ 500, and QRS < 120, followed by a natural language search for electronic records with "Torsades," "polymorphic VT," or similar to identify TdP cases from 2005 to 19. We identified controls from a similar ECG database search matching for QTc, heartrate, age, and sex. We compared cardiologic and historical factors, medications, laboratory values, and ECG measurements including ectopy using univariate statistics. For those cases with saved telemetry strips that included preceding beats or TdP onset, we compared ectopy and TdP onset characteristics between the ECG and telemetry strips using mixed linear modeling.

RESULTS

Seventy-five cases including 50 with telemetry strips and 150 controls were included. Historical, pharmacologic, laboratory, and cardiologic testing results were similar between cases and controls. The proportion of telemetry tracings with premature ventricular contractions (PVC's) preceding TdP was 0.78 compared to 0.16 for case ECG's (difference 0.62(95%CI 0.44-0.75)) and 0.10 for control ECGs (difference 0.68(95%CI 0.56-0.80)). Average telemetry heartrate was 72 and QTc 549 immediately preceding TdP, similar to the ECG values.

CONCLUSIONS

Clinical factors don't differentiate patients with long QTc who develop TdP, however, an increase in PVC's in patients with prolonged QTc may usefully predict imminent TdP.

Association of systemic immune inflammation index and system inflammation response index with clinical risk of acute myocardial infarction

Background

Systemic immune inflammatory index (SII) and systemic inflammatory response index (SIRI) are combinations of non-specific inflammatory and adaptive immune response impairments associated with cardiovascular disease. Yet little analysis has been done on SII, SIRI and acute myocardial infarction (AMI) prognosis. The purpose of this study was to investigate the correlation of SII and SIRI with clinical risk factors such as GRACE, Gensini, and QTc after acute myocardial infarction.

Methods

This study enrolled 310 patients with AMI from February 1, 2018, to December 31, 2022, at our institution. Routine blood items calculated SII and SIRI. Two groups were divided according to whether MACE occurred: the MACE group (81 cases) and the NMACE group (229 cases); each group was divided into three groups according to the SII and SIRI tertiles. The relationship between SII, SIRI and MACE was analyzed using multifactorial logistic regression analysis after adjusting for confounders; ROC curves were plotted to examine the predictive value of SII and SIRI for MACE. The correlation between SII and SIRI and potential risk factors such as Gensini, QTc and GRACE was further analyzed.

Results

The study enrolled 310 patients, comprising 248 men (80%, mean age 60.73 ± 13.695 years) and 62 women (20%, mean age 69.79 ± 11.555 years). In the regression model completely adjusted for confounders, the risk of MACE was higher in AMI patients with SII > 11.00 [OR = 1.061,95% CI (1.018,1.105)] than in SII < 5.98; the risk of MACE was 115.3% higher in AMI patients with SIRI (1.72-3.68) [OR = 2.153, 95% CI (1.251, 3.705)] was 115.3% higher in AMI patients with SIRI < 1.72 and the risk of MACE was 25.1% higher in AMI patients with SIRI > 3.68 [OR = 1.251, 95% CI (1.123, 1.394)] than in AMI patients with SIRI < 1.72. In addition, SII, SIRI, and potential post-infarction risk factors (Gensini, QTc, and GRACE) were also associated.

Conclusion

SII and SIRI have been significantly associated with post-myocardial infarction MACE and the predictive potential clinically integrated risk factors in AMI patients, for which more attention should be paid to targeted anti-inflammatory therapy in AMI patients to further reduce the incidence of prognostic MACE in AMI patients.

Effects of Bedaquiline Combined with Fluoroquinolone and/or Clofazimine on QT Interval in Patients with Multidrug-Resistant Tuberculosis: a Retrospective Study

With the application of bedaquiline (Bdq), the success rate of multidrug-resistant tuberculosis (MDR-TB) treatment has been significantly improved; however, the cardiac safety of the patients during treatment cannot be ignored. Hence, this study compared the effects of bedaquiline alone and bedaquiline combined with fluoroquinolones (FQs) and/or clofazimine (CFZ) on the QT interval. This single-center retrospective cohort study analyzed the clinical data of MDR-TB patients treated with bedaquiline for 24 weeks from January 2020 to May 2021 in Xi'an Chest Hospital and compared the changes in QTcF between the two groups. Eighty-five patients were included in the study and grouped by types of anti-TB drugs affecting the QT interval they used. Group A included bedaquiline (n = 33), and group B included bedaquiline in combination with fluoroquinolones and/or clofazimine (n = 52). Out of patients with available corrected QT interval by Fridericia's formula (QTcF) data, 2.4% (2/85) experienced a postbaseline QTcF of ≥500 ms, and 24.7% (21/85) had at least one change of QTcF of ≥60 ms from baseline. In group A, 9.1% (3/33) had at least one ΔQTcF of >60 ms, as did 34.6% (18/52) of group B. Multivariate Cox regression analysis showed that the adjusted risk of QT prolongation was 4.82 times higher in group B (95% confidence interval [CI], 1.406 to 16.488). Bedaquiline combined with other anti-TB drugs affecting QT interval significantly increased the incidence of grade 3 or 4 QT prolongation; however, no serious ventricular arrhythmia and permanent drug withdrawal occurred. The use of bedaquiline combined with fluoroquinolone and/or clofazimine is an independent risk factor affecting QT interval. IMPORTANCE Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis. The emergence of MDR-TB is caused by an organism that is resistant to at least isoniazid and rifampin and is currently considered the major challenge for the global control of TB. Bedaquiline is the first new TB drug in 50 years with a unique mechanism of action, strong anti-M. tuberculosis activity. Yet unexplained excess deaths in the bedaquiline arms have been found in some phase II clinical trials; thus, the FDA has issued a "boxed warning." However, the cardiac safety of the patients during treatment cannot be ignored. Accordingly, further investigations are needed to establish whether bedaquiline combined with clofazimine, fluoroquinolones, or anti-TB drugs affecting the QT interval in a long-course or short-course treatment increases the risk of QT prolongation.

Management of Atrial Arrhythmias After Lung Transplant

The overall survival in patients undergoing lung transplantation is poor. Although postsurgical atrial arrhythmias seem to play a major role in the morbidity and mortality of this population, data regarding the clinical and interventional management of this complication are still controversial. Through a review of the literature in the field, we observed that not only the surgical technique is clearly arrhythmogenic, but the new administration of peri-procedure beta-blockers and amiodarone for arrhythmia prevention and treatment, respectively, seems harmful in these postsurgical patients. However, low-dose beta-blockers administered after surgery seem feasible in arrhythmia prevention in specific patient subgroups, and, aside from amiodarone, alternative antiarrhythmic agents can be safely and effectively used to treat symptomatic patients on top of adequate rate control. Finally, as to complex atrial arrhythmias occurring late after lung transplant surgery, radiofrequency catheter ablation seems a feasible treatment option. In light of this evidence and considering the absence of clear recommendations in the field, we suggest a practical approach that may help the clinician in the management of this postsurgical complication. However, as most of these considerations are drawn from small-sized and retrospective studies, more evidence is needed in the future to clarify which medical and interventional strategies may best treat these postsurgical arrhythmias and thus potentially improve the outcome of these frail patients.

Unraveling Structural Alerts in Marketed Drugs for Improving Adverse Outcome Pathway Framework of Drug-Induced QT Prolongation

In pharmaceutical treatment, many non-cardiac drugs carry the risk of prolonging the QT interval, which can lead to fatal cardiac complications such as torsades de points (TdP). Although the unexpected blockade of ion channels has been widely considered to be one of the main reasons for affecting the repolarization phase of the cardiac action potential and leading to QT interval prolongation, the lack of knowledge regarding chemical structures in drugs that may induce the prolongation of the QT interval remains a barrier to further understanding the underlying mechanism and developing an effective prediction strategy. In this study, we thoroughly investigated the differences in chemical structures between QT-prolonging drugs and drugs with no drug-induced QT prolongation (DIQT) concerns, based on the Drug-Induced QT Prolongation Atlas (DIQTA) dataset. Three categories of structural alerts (SAs), namely amines, ethers, and aromatic compounds, appeared in large quantities in QT-prolonging drugs, but rarely in drugs with no DIQT concerns, indicating a close association between SAs and the risk of DIQT. Moreover, using the molecular descriptors associated with these three categories of SAs as features, the structure–activity relationship (SAR) model for predicting the high risk of inducing QT interval prolongation of marketed drugs achieved recall rates of 72.5% and 80.0% for the DIQTA dataset and the FDA Adverse Event Reporting System (FAERS) dataset, respectively. Our findings may promote a better understanding of the mechanism of DIQT and facilitate research on cardiac adverse drug reactions in drug development.

Torsades De Pointes in a 71-Year-Old Female With Normal Qt Interval After Azithromycin Use

A 71-year-old female visiting from Colombia presented to the emergency room with a productive cough, subjective fever, and chills for the past three days. Baseline EKG demonstrated a QT interval of 385 milliseconds with left ventricular hypertrophy and T wave inversions in leads V4, V5, and V6. Azithromycin was administered, and she was subsequently found to have torsades de pointes (TdP) on telemetry. In high-risk individuals, medications with reduced effects on cardiac conduction should be considered to avoid potentially lethal reactions. This case highlights the importance of clinical history prior to the administration of medications that have a propensity to cause abnormalities in cardiac conduction. Our patient had a grossly normal QT interval prior to the administration of azithromycin; however, she subsequently developed torsades de pointes. The patient was on telemetry monitoring, and cardiopulmonary resuscitation was quickly initiated as she was in a hospitalized setting; however, in an outpatient community setting, she likely would not have survived. By examining all the elements which contribute to QT prolongation, clinicians can have a deeper understanding of the complexities, particularly in individuals with multiple co-morbid conditions prior to the administration of medications that have a propensity to affect the QT interval.

Perspective on Antiarrhythmic Drug Combinations

Physicians use multiple drugs in combination to treat hypertension, heart failure, diabetes mellitus, angina, hyperlipidemia, and many other cardiovascular conditions and risk factors. However, administering antiarrhythmic drugs (AAD) in combination is rarely discussed. Yet, the possibility of increasing efficacy and/or tolerance and/or safety of AADs (by adding mechanisms, offsetting adverse mechanisms, and/or using lower doses) exists. Unfortunately, this topic has not been reviewed in any contemporary cardiac literature of which we are aware, although information regarding AAD combinations has been published. In conclusion, and accordingly, this review discusses the possibility of using AAD combinations for both ventricular arrhythmias and atrial fibrillation, in which the rationale for such combinations, considerations for such combinations, and supporting literature are covered.

The Effects of Moxifloxacin and Gemifloxacin on the ECG Morphology in Healthy Volunteers: A Phase 1 Randomized Clinical Trial

Moxifloxacin and gemifloxacin are the two newer broad-spectrum 8-methoxy-quinolone derivatives that are used to treat various bacterial infections in cardiac patients. In this research study, we assessed the impact of moxifloxacin and gemifloxacin on the QT intervals of electrocardiograms in normal adult doses and draw a comparison, in a controlled environment, on healthy volunteers. Additionally, the effect of both test drugs on the QRS complex was checked. Sixty healthy volunteers were randomly assigned to two groups via R-software, and each respectively received moxifloxacin and gemifloxacin for five days. The research ethics committee approved the research, and it was registered for clinical trial under NCT04692623. The participants' electrocardiograms were obtained before the start of the dose (baseline) and on the fifth day. Significant prolongation of QT interval was noted in moxifloxacin (p < 0.0001) as compared to gemifloxacin treated groups. There were no cases of QTc prolongation over the usual limits (450-470 ms) in the gemifloxacin-treated group, however, QTc prolongations at the rate of 30 and 60 ms from the baseline were noted, interpreted as per the EMEA guidelines. These findings indicate that moxifloxacin caused significant (p < 0.0001) QT interval prolongation (QTIP) as compared to gemifloxacin. In contrast to the previously reported literature, the prominent effect of moxifloxacin on the widening of the QRS-complex was noted with no such effect on QRS-widening in the gemifloxacin-treated group. It is concluded that both drugs have the potential for considerable QT interval prolongation (QTIP) effects, which is one of the risk factors for developing torsade de pointes (TdPs) in cardiac patients. Thus, clinicians should exercise caution when prescribing moxifloxacin and gemifloxacin to cardiac patients and should consider alternate treatment options.

Association between pre-operative prolonged corrected QT interval and all-cause mortality after non-cardiac surgery

BACKGROUND

Prolonged corrected QT interval (QTc) has been linked to risk of arrhythmias and mortality in the general population. Pre-operative electrocardiography is often obtained for patient-and procedural cardiovascular risk assessment. The aim of this study was to investigate the association of pre-operative QTc and all-cause mortality in a non-cardiac surgical cohort.

METHODS

A retrospective study of all patients over 18 years undergoing non-cardiac surgery at Landspitali-the National University Hospital in Iceland between 2 January 2005 to 31 December 2015, with follow-up through 20 May 2016. Patients were separated into five categories according to their pre-operative QTc interval ≤ 379, 380-439 (reference group), 440-479, 480-519 and ≥520 ms. Primary outcome was long-term mortality and secondary outcome was 30-day mortality.

RESULTS

A total of 10,209 surgeries for 10,209 individuals were included. The median follow-up for mortality was 2691 days (interquartile range [IQR] 1620-3705 days). Patients with longer QTc interval had a higher comorbidity burden, were more likely to undergo emergency surgery and were often prescribed cardiac medications. After adjustment for confounding variables, the hazard ratio (HR) for long-term mortality compared with reference (QTc 380-439 ms) was 0.85 [CI: 0.66-1.09] for QTc ≤379, 1.08 [CI: 0.99-1.17] for QTc 440-479 ms, 1.26 [CI: 1.10-1.43] for QTc between 480 and 519 ms and 0.97 [CI: 0.78-1.21] for QTc ≥520 ms. When compared with reference, only patients with QTc interval between 480 and 519 ms had higher odds ratio for 30-day mortality as odds ratio for other groups were following; 1.12 [CI: 0.18-3.8] for ≤379 ms, 1.03 [CI: 0.70-1.51] for QTc 440-479 ms, 1.64 [CI: 1.02-2.60] for QTc 480-519 ms and 0.98 [0.44-2.06] for QTc ≥520 ms.

CONCLUSION

Pre-operative QTc between 480 and 519 ms is associated with both higher long-term and 30-day mortality after non-cardiac surgery. The results suggest that this could reflect an underlying cardiovascular risk.

Relationship between a risk score for QT interval prolongation and mortality across rural and urban inpatient facilities

OBJECTIVES

To evaluate the relationship between a modified Tisdale QTc-risk score (QTc-RS) and inpatient mortality and length of stay in a broad inpatient population with an order for a medication with a known risk of torsades de pointes (TdP).

BACKGROUND

Managing the risk of TdP is challenging due to the number of medications with known risk of TdP and the complexity of precipitating factors. A model to predict risk of mortality may be useful to guide treatment decisions.

METHODS

This was a retrospective observational study using inpatient data from 28 healthcare facilities in the western United States. This risk score ranges from zero to 23 with weights applied to each risk factor based on a previous validation study. Logistic regression and a generalized linear model were performed to assess the relationship between QTc-RS and mortality and length of stay.

RESULTS

Between April and December 2020, a QTc-RS was calculated for 92,383 hospitalized patients. Common risk factors were female (55.0%); age > 67 years (32.1%); and receiving a medication with known risk of TdP (24.5%). A total of 2770 (3%) patients died during their hospitalization. Relative to patients with QTc-RS < 7, the odds ratio for mortality was 4.80 (95%CI:4.42-5.21) for patients with QTc-RS = 7-10 and 11.51 (95%CI:10.23-12.94) for those with QTc-RS ≥ 11. Length of hospital stay increased by 0.7 day for every unit increase in the risk score (p < 0.0001).

CONCLUSION

There is a strong relationship between increased mortality as well as longer duration of hospitalization with an increasing QTc-RS.

CYP2D6 Substrate Dispensing Among Patients Dispensed Mirabegron: An Administrative Claims Analysis

BACKGROUND

Overactive bladder (OAB) is characterized by the presence of bothersome urinary symptoms. Pharmacologic treatment options for OAB include anticholinergics and β3-adrenergic agonists. Use of β3-adrenergic agonists may result in similar treatment efficacy with a decreased side effect profile compared with anticholinergics because high anticholinergic burden is associated with cardiovascular and neurologic side effects. However, the β3-adrenergic agonist mirabegron, one of two approved drugs within this class, is a moderate cytochrome P450 (CYP) 2D6 inhibitor, and coadministration of drugs that are CYP2D6 substrates with mirabegron may lead to adverse drug effects.

OBJECTIVE

The aim of this study was to quantify how often CYP2D6 substrates were dispensed in patients receiving mirabegron among adults of any age and among those ≥ 65 years of age.

METHODS

In this retrospective descriptive analysis, a deidentified administrative claims database in the United States, IQVIA PharMetrics® Plus, was used to identify dispensing claims for CYP2D6 substrates and mirabegron from November 2012 to September 2019. Prevalence of CYP2D6 substrate dispensing was assessed in patients dispensed mirabegron among all adults ≥ 18 years old and additionally among a cohort of those ≥ 65 years old. Patient baseline profiles at the time of mirabegron and CYP2D6 substrate codispensing and at the time of mirabegron dispensing were compared. CYP2D6 substrates were categorized as those with the potential for increased risk of QT prolongation, with anticholinergic properties, with narrow therapeutic index (NTI), contraindicated or having a black box warning when used with CYP2D6 inhibitors, or used for depression or other psychiatric disease. Dispensing data and patient profiles were summarized descriptively.

RESULTS

Overall, 68.5% of adults ≥ 18 years old dispensed mirabegron had overlapping dispensings for one or more CYP2D6 substrate; 60.6% and 53.6% had overlapping dispensings for CYP2D6 substrates with anticholinergic properties or risk of QT prolongation, respectively. CYP2D6 substrates with NTI, contraindicated with CYP2D6 inhibitors, or for psychiatric use were codispensed in 17.7%, 16.6%, and 38.0% of adult mirabegron users, respectively. Mirabegron users receiving one or more concurrent CYP2D6 substrate were more likely to be older, have more comorbidities and baseline polypharmacy, and have increased healthcare resource utilization compared with those without concurrent CYP2D6 substrates. Commonly codispensed CYP2D6 substrates included hydrocodone, oxycodone, tramadol, metoprolol, and tamsulosin. Findings were similar for patients in the older cohort (≥ 65 years old), with 72.1% receiving overlapping CYP2D6 substrates.

CONCLUSIONS

Codispensing of CYP2D6 substrates, especially those with anticholinergic properties or risk of QT prolongation, was common among adults and older adults receiving mirabegron. Results highlight the need for improved awareness of CYP2D6 substrate prescribing among patients receiving pharmacologic treatment for OAB that inhibits the CYP2D6 pathway.

Temporal change in repolarization parameters after surgical correction of valvular heart diseases

BACKGROUND

Ventricular tachyarrhythmia is a potentially fatal outcome of cardiac surgery. Abrupt changes in the hemodynamics after surgical correction of valvular heart disease (VHD) can lead to alterations in ventricular repolarization. We compared the difference between temporal changes in repolarization parameters after correction of left-sided VHD.

METHODS

We retrospectively analyzed the electrograms of patients who underwent surgical correction of isolated VHD between 2006 and 2015 at Asan Medical Center, including mitral stenosis (MS), mitral regurgitation (MR), aortic stenosis (AS), and aortic regurgitation (AR). Ventricular repolarization parameters were measured at pre-specified time intervals after index surgery using a custom-made ECG analysis program. We compared repolarization parameters, including QT and corrected QT intervals, T peak-to-end interval, and corrected T peak-to-end interval.

RESULTS

Analysis of 8265 ECGs from 2110 patients (266 MS, 1059 MR, 421 AS, and 364 AR) was performed. Patients with AS were characterized by older age and more comorbidities than other VHDs. The corrected QT interval showed a peak value immediately after surgery and decreased thereafter in the AS groups. However, a gradual increase over 1 month after surgery in AR, MS, and MR groups was observed. The corrected T peak-to-end interval increased in the MS and MR groups and was unchanged in the AS and AR groups.

CONCLUSIONS

The repolarization parameters of surgery changed dynamically after left-sided valvular surgery. Understanding differential temporal change of repolarization parameters according to the type of VHD would help clinicians avoid fatal arrhythmias related to the repolarization changes.

High-Throughput Assessment of Real-World Medication Effects on QT Interval Prolongation: Observational Study

BACKGROUND

Drug-induced prolongation of the corrected QT interval (QTc) increases the risk for Torsades de Pointes (TdP) and sudden cardiac death. Medication effects on the QTc have been studied in controlled settings but may not be well evaluated in real-world settings where medication effects may be modulated by patient demographics and comorbidities as well as the usage of other concomitant medications.

OBJECTIVE

We demonstrate a new, high-throughput method leveraging electronic health records (EHRs) and the Surescripts pharmacy database to monitor real-world QTc-prolonging medication and potential interacting effects from demographics and comorbidities.

METHODS

We included all outpatient electrocardiograms (ECGs) from September 2008 to December 2019 at a large academic medical system, which were in sinus rhythm with a heart rate of 40-100 beats per minute, QRS duration of <120 milliseconds, and QTc of 300-700 milliseconds, determined using the Bazett formula. We used prescription information from the Surescripts pharmacy database and EHR medication lists to classify whether a patient was on a medication during an ECG. Negative control ECGs were obtained from patients not currently on the medication but who had been or would be on that medication within 1 year. We calculated the difference in mean QTc between ECGs of patients who are on and those who are off a medication and made comparisons to known medication TdP risks per the CredibleMeds.org database. Using linear regression analysis, we studied the interaction of patient-level demographics or comorbidities on medication-related QTc prolongation.

RESULTS

We analyzed the effects of 272 medications on 310,335 ECGs from 159,397 individuals. Medications associated with the greatest QTc prolongation were dofetilide (mean QTc difference 21.52, 95% CI 10.58-32.70 milliseconds), mexiletine (mean QTc difference 18.56, 95% CI 7.70-29.27 milliseconds), amiodarone (mean QTc difference 14.96, 95% CI 13.52-16.33 milliseconds), rifaximin (mean QTc difference 14.50, 95% CI 12.12-17.13 milliseconds), and sotalol (mean QTc difference 10.73, 95% CI 7.09-14.37 milliseconds). Several top QT prolonging medications such as rifaximin, lactulose, cinacalcet, and lenalidomide were not previously known but have plausible mechanistic explanations. Significant interactions were observed between demographics or comorbidities and QTc prolongation with many medications, such as coronary disease and amiodarone.

CONCLUSIONS

We demonstrate a new, high-throughput technique for monitoring real-world effects of QTc-prolonging medications from readily accessible clinical data. Using this approach, we confirmed known medications for QTc prolongation and identified potential new associations and demographic or comorbidity interactions that could supplement findings in curated databases. Our single-center results would benefit from additional verification in future multisite studies that incorporate larger numbers of patients and ECGs along with more precise medication adherence and comorbidity data.