Estimation of cardiac QTc intervals in people prescribed antipsychotics: a comparison of correction factors

Overcoming clozapine's adverse events: a narrative review of systematic reviews and meta-analyses

INTRODUCTION

Clozapine is the gold standard treatment for treatment resistant schizophrenia, however adverse events remain a clinical challenge.

AREAS COVERED

This review presents a narrative synthesis of systematic reviews and meta-analyses that have reported the onset, incidence, prevalence, and management of clozapine's adverse events. We conducted a systematic literature search using PubMed, Embase, PsycINFO, OvidMEDLINE, CINAHL, and the Cochrane Database of Systematic Reviews from inception to April 2024.

EXPERT OPINION

Effective management of clozapine's adverse events necessitates multi-faceted, individualized, and shared-decision strategies. Despite a lack of high-quality systematic evidence, expert inter-disciplinary solutions are provided to help address a critical need for clinical guidance. This 35-year update offers an evidence-based framework to assist clinicians, patients, and caregivers navigate the adverse events associated with clozapine therapy.

QTc intervals at rest and during exercise assessed by group correction formulas in survivors of childhood acute lymphoblastic leukemia

INTRODUCTION

Early signs of subclinical cardiac damage must be identified before they turn into clinical manifestations. Tailoring a formula is relevant for precise QTc evaluation in childhood acute lymphoblastic leukemia (ALL) survivors considering they are at risk of long-term cardiac problems. Therefore, we aim to develop group heart rate correction formulas for QT intervals in childhood ALL survivors at rest and during exercise, and to assess the applicability of these methods across a variety of risk groups exposed to diverse chemotherapy dosages.

METHODS

Two hundred and fifty childhood ALL survivors in the PETALE study were classified into 3 groups depending on their prognostic risk group. ECG measurements (QT and RR intervals) were made at rest and during a cardiopulmonary exercise test. QT correction for heart rate was applied using 5 different formulas, which included 2 previously published formulas and 3 group-specific formulas for each sex.

RESULTS

The QT/RR relation showed 2 different curves between rest and during exercise, which was worse for females. Group-specific QTc formulas allowed adequate heart rate-corrected QT interval, independently of the cumulative dose of doxorubicin received during treatment. Group-specific formulas showed significantly shorter QTc intervals than QTc from Bazett's formula. QTc (Bazett's formula) values surpassed the established clinical norm in 22 males (11%) and 22 females (11%), with a majority occurring during exercise, affecting 15 males (7.5%) and 10 females (5%).

CONCLUSION

This study shows the applicability of personalized group correction of QT/RR data in childhood ALL survivors. Our comprehensive assessments (spanning rest, exercise, and recovery) is an effective approach for risk stratification of cardiac complications in childhood ALL survivors.

Investigation of carotid intima-media thickness in patients with schizophrenia

BACKGROUND

Patients with schizophrenia (SCZ) have a higher risk of cardiovascular diseases than the average population. Early diagnosis of SCZ patients with subclinical atherosclerosis is great importance in reducing cardiovascular morbidity and mortality. The aim of this study was to investigate some clinical risk factors for atherosclerosis in patients with SCZ.

METHODS

Fifty-one SCZ patients (20 females, 31 males) and 55 healthy controls (HCs) (25 females, 30 males) were included in the study. Electrocardiography (ECG), lipid parameters, hemogram, and biochemistry values of the participants were taken. Low-density lipoprotein (LDL), high-density lipoprotein (HDL), fasting triglycerides, and total cholesterol were measured. The arrhythmogenic index of plasma (AIP) was analyzed. The recorded right and left carotid intima-media thickness (CIMT) measurements by carotid ultrasonography were scanned.

RESULTS

QT interval (p = 0.035), CIMT-left (p = 0.008), CIMT-right (p = 0.002), fasting triglyceride (p = 0.005), AIP (p = 0.005) in the SCZ group compared to HCs (< 0.001) was statistically higher, while HDL (p = 0.003) was statistically lower. Smoking rates, QT interval (p = 0.035), CIMT-left (p = 0.008), and CIMT-right (p = 0.002) were significantly higher in the the SCZ group than in the HCs. According to odds ratios, individuals with SCZ have a 6.3-fold higher smoking rate. According to Pearson correlation analysis, CIMT-left was positively correlated with age and QT interval (r = 0.568, p < 0.001 and r = 0.589, p < 0.001, respectively). CIMT-right value was also positively correlated with age and QT interval (r = 0.533, p < 0.001 and r = 0.555, p < 0.001, respectively). QT interval positively and significantly predicted CIMT-left and CIMT-right (p < 0.001, β = 0.549 and p = 0.001 and β = 0.506 accordingly).

CONCLUSION

In this study, a close relationship was found between the QT interval and CIMT in SCZ patients. This finding could be valuable for using an easy-to-calculate data such as QT in place of a laborious test such as CIMT.

Risk Stratification of QTc Prolongation in Critically Ill Patients Receiving Antipsychotics for the Management of Delirium Symptoms

BACKGROUND

Patients experiencing significant agitation or perceptual disturbances related to delirium in an intensive care setting may benefit from short-term treatment with an antipsychotic medication. Some antipsychotic medications may prolong the QTc interval, which increases the risk of potentially fatal ventricular arrhythmias. In this targeted review, we describe the evidence regarding the relationships between antipsychotic medications and QTc prolongation and practical methods for monitoring the QTc interval and mitigating arrhythmia risk.

METHODS

Searches of PubMed and Cochrane Library were performed to identify studies, published before February 2023, investigating the relationships between antipsychotic medications and QTc prolongation or arrhythmias.

RESULTS

Most antipsychotic medications commonly used for the management of delirium symptoms (eg, intravenous haloperidol, olanzapine, quetiapine) cause a moderate degree of QTc prolongation. Among other antipsychotics, those most likely to cause QTc prolongation are iloperidone and ziprasidone, while aripiprazole and lurasidone appear to have minimal risk for QTc prolongation. Genetic vulnerabilities, female sex, older age, pre-existing cardiovascular disease, electrolyte abnormalities, and non-psychiatric medications also increase the risk of QTc prolongation. For individuals at risk of QTc prolongation, it is essential to measure the QTc interval accurately and consistently and consider medication adjustments if needed.

CONCLUSIONS

Antipsychotic medications are one of many risk factors for QTc prolongation. When managing agitation related to delirium, it is imperative to assess an individual patient's risk for QTc prolongation and to choose a medication and monitoring strategy commensurate to the risks. In intensive care settings, we recommend regular ECG monitoring, using a linear regression formula to correct for heart rate. If substantial QTc prolongation (eg, QTc > 500 msec) is present, a change in pharmacologic treatment can be considered, though a particular medication may still be warranted if the risks of discontinuation (eg, extreme agitation, removal of invasive monitoring devices) outweigh the risks of arrhythmias.

AIMS

This review aims to summarize the current literature on relationships between antipsychotic medications and QTc prolongation and to make practical clinical recommendations towards the approach of antipsychotic medication use for the management of delirium-related agitation and perceptual disturbances in intensive care settings.