QTc variability in schizophrenia patients treated with antipsychotics and healthy controls

QT interval prolongation noted in one percent of 2553 Asian patients with schizophrenia: Findings from the REAP-AP survey

Although the association between antipsychotic use and corrected QT interval (QTc) prolongation has been repeatedly confirmed, the relationship has been rarely studied in a practical setting. Using data from the Research on Asian Psychotropic Prescription Patterns for Antipsychotics (REAP-AP) survey, our study aimed to investigate the prevalence and clinical correlates of QTc prolongation in 2553 Asian patients with schizophrenia. After adjusting for the potential effect of confounding factors, the baseline and clinical characteristics of the schizophrenia patients with and without QTc prolongation were compared using analyses of covariance and binary logistic analyses. In addition, a binary logistic analysis model with a forward selection method was used to identify the distinctive clinical correlates of QTc prolongation. QTc prolongation was noted in 1.1% of Asian patients with schizophrenia. Schizophrenia patients were characterized by lower proportions of disorganized speech and negative symptoms; higher use of amisulpride and clozapine; and higher proportions of rigidity, hypercholesterolemia, and sedation than those without QTc prolongation. Finally, a binary logistic mode showed that amisulpride, clozapine, rigidity, and hypercholesterolemia might be the distinctive clinical correlates of QTc prolongation in Asian patients with schizophrenia. These findings indicate the clinical implications that the uses of amisulpride and clozapine and the occurrences of rigidity and hypercholesterolemia may be potential risk factors for QTc prolongation of schizophrenia patients.

Twenty-Four-Hour Measures of Heart Rate-Corrected QT Interval, Peak-to-End of the T-Wave, and Peak-to-End of the T-Wave/Corrected QT Interval Ratio During Antipsychotic Treatment

PURPOSE/BACKGROUND

Prolonged ventricular repolarization, measured by heart rate-corrected QT interval (QTc) prolongation, might be a biomarker for risk of torsade de pointes (TdP) and sudden cardiac death. However, the predictive value of QTc has been challenged, and a component of QTc, peak-to-end of the T-wave (Tpe), and a high Tpe/QT ratio might be superior biomarkers because they better reflect increased transmural dispersion of ventricular myocyte repolarization, which can lead to TDP. The purpose of this pilot study was to provide the first measurements of heart rate, QTc, Tpe, Tpe/QTc, and their variability over 24 hours in medication-free patients with schizophrenia, during treatment with ziprasidone or other antipsychotic drugs, and healthy controls.

METHODS

Subjects included 12 patients treated with ziprasidone, 30 treated with other antipsychotic drugs, 3 unmedicated patients, and 15 normal controls. Subjects underwent 24-hour analog Holter recording, and the recordings were digitized. A cardiologist blind to treatment selected multiple 10-cycle segments throughout each recording and measured the electrocardiogram metrics.

RESULTS

Variability in QTc, Tpe, and Tpe/QTc over the 24 hours was present in all groups; 91.1% of patients and 100% of controls had 1 or more QTc values of 450 milliseconds or greater. Mean QTc length was significantly greater in the ziprasidone-treated than the non-ziprasidone-treated patients (P = 0.02). Mean Tpe was not elevated in the ziprasidone patients, whereas mean Tpe/QTc was lower (P < 0.01).

CONCLUSIONS

The large variability in QTc, Tpe, and Tpe/QTc observed supports the need for 24-hour electrocardiogram recordings to provide an accurate assessment of risk of TdP. Heart rate-corrected QT interval alone does not capture the risk of TdP.

QTc interval lengthening in first-episode schizophrenia (FES) patients in the earliest stages of antipsychotic treatment

Antipsychotic use is reported to be associated with a higher risk of sudden cardiac death and new users are especially susceptible to that risk. In this study, we focused on the ability of antipsychotics to prolong the QTc interval at the earliest stages of antipsychotic use. We employed a retrospective cohort study design in a naturalistic setting where having three ECG measurements over time (at baseline and after drug exposure) in antipsychotic-naïve, first-episode schizophrenia (FES) inpatients. The results revealed, in this relatively homogeneous, drug naïve FES patient sample, that QTc intervals were statistically significantly prolongated after a relatively short term (2-4weeks) of antipsychotic treatments, compared with baseline. After about 2 or 4weeks of antipsychotic use, the risk of abnormal QTc prolongation was higher than at baseline. These results reinforce the importance of monitoring risk factors and assessing QTc prolongation at the beginning and throughout treatment with antipsychotics.

[Antipsychotic Treatment of the Adult Patient in the Acute Phase of Schizophrenia]

OBJECTIVES

To determine the efficacy and safety of different antipsychotic drugs in the management of patients diagnosed with schizophrenia in the acute phase. To formulate evidence-based recommendations on the antipsychotic (AP) drug management strategies for the treatment of the adult diagnosed with schizophrenia in the acute phase.

METHOD

Clinical practice guidelines were prepared, using the guidelines of the Methodology Guide of the Ministry of Health and Social Protection, in order to identify, synthesise, and evaluate the evidence and formulate recommendations as regards the management and follow-up of adult patients diagnosed with schizophrenia. The evidence of the NICE 82 guideline was adopted and updated, which answered the question on the management of the acute phase of adults with a diagnosis of schizophrenia. The evidence and its level were presented to the Guideline Development Group (GDG) in order to formulate recommendations following the methodology proposed by the GRADE approach.

RESULTS

Clozapine, olanzapine, risperidone, ziprasidone, amisulpride, paliperidone, haloperidol, quetiapine, and aripiprazole were more effective than placebo for the majority of psychotic symptoms and the abandonment of treatment, but asenapine was not. Paliperidone, risperidone, quetiapine, clozapine, and olanzapine showed significant increases in weight compared to placebo. Haloperidol, risperidone, ziprasidone, and paliperidone had a higher risk of extrapyramidal symptoms than placebo. There was a significant risk of sedation or drowsiness with, risperidone, haloperidol, ziprasidone, quetiapine, olanzapine, and clozapine in the comparisons with placebo. Of the results of the comparisons between AP, it was shown that clozapine and paliperidone had a clinically significant effect compared to haloperidol and quetiapine, respectively. Olanzapine and risperidone had a lower risk of abandoning the treatment in general, and due to adverse reactions in two comparisons of each one, haloperidol was the drug with more risk of abandoning due to adverse effects, followed by clozapine. Amisulpride, haloperidol and ziprasidone had favourable results as regards weight increase in several comparisons. Aripiprazole and paliperidone obtained a higher number of favourable results as regards sedation, and all the atypical drugs (except paliperidone) had a lower risk than the use of anti-parkinsonian drugs. Of the evidence from observational studies, it was found that, in subjects with risk factors for diabetes, such as age, hypertension, and dyslipidaemia, the initial treatment and current treatment with olanzapine, as well as current treatment with clozapine, may promote the development of this disease.

CONCLUSION

Although it is imperative to prescribe an antipsychotic for treatment of the acute phase, the selection of the drug depends on the particular clinical condition of each patient and their collateral effects profile.

Clinical pharmacology of dopamine-modulating agents in Tourette's syndrome

Forty years of research and clinical practice have proved dopamine (DA) receptor antagonists to be effective agents in the treatment of Tourette's syndrome (TS), allowing a significant tic reduction of about 70%. Their main effect seems to be mediated by the blockade of the striatal DA-D2 receptors. Various typical and atypical agents are available and there is still discord between experts about which of them should be considered as first choice. In addition, there are suggestions to use DA receptor agonists such as pergolide or non-DA-modulating agents. The present chapter is focusing on the clinical pharmacology of DA-modulating agents in the treatment of TS. The introduction outlines their clinical relevance and touches on the hypotheses of the role of DA in the pathophysiology of TS. Subsequently, general information about the mechanisms of action and adverse effects are provided. The central part of the chapter forms a systematic review of all DA-modulating agents used in the treatment of TS, including an overview of studies on their effectiveness, and a critical discussion of their specific adverse effects. The present chapter closes with a summary of the body of evidence and a description of the resulting recommendations for the pharmacological treatment of TS.

Therapeutic drug monitoring of common antipsychotics

The aim of this review is to provide information for interpreting outcome results from monitoring of antipsychotics in biological samples. A brief overview of the working mechanisms, pharmacological effects, drug interactions, and analytical methods of classical and atypical antipsychotics is given. Nineteen antipsychotics were selected based on their importance in the worldwide market as follows: amisulpride, aripiprazole, asenapine, bromperidol, clozapine, flupenthixol, haloperidol, iloperidone, lurasidone, olanzapine, paliperidone, perphenazine, pimozide, pipamperone, quetiapine, risperidone, sertindole, sulpiride, and zuclopenthixol. A straightforward relationship between administered dose, plasma or serum concentration, clinical outcome, or adverse effects is often lacking. Nowadays, focus lies on therapeutic drug monitoring and individualized therapy to find adequate treatment, to explain treatment failure or nonresponse, and to check patient compliance. However, extensive research in this field is still mandatory.

QTc interval and its variability in patients with schizophrenia and healthy subjects: implications for a thorough QT study

We compared heart rate-corrected QT interval (QTc) and its within- and between-subject variability, in ECGs recorded several days apart for 207 patients with schizophrenia (age range 19-60 yr) with age- and gender-matched healthy controls. Patients had higher heart rates (mean±s.d.) than controls [75±15 beats per minute (bpm) vs. 63±10 bpm; p<0.0001]. QTc by Bazett's formula (QTcB) overestimated QTc interval at high heart rates; consequently QTcB was longer in patients (412±24 ms) than in controls (404±24 ms; p=0.0003). QTc by Fridericia's method (QTcF), which was not influenced by heart rate, was comparable (398±22 ms in patients vs. 401±19 ms in controls; p=0.17). Between-subject variability in QTcF was similar in patients (17 ms) and controls (16.2 ms) but within-subject variability was larger (13.1 ms vs. 10 ms, respectively). Thus, a larger sample size is required when thorough QTc studies with a cross-over design are performed in patients with schizophrenia than in healthy subjects; sample size is not increased for studies with a parallel design. Last, QTcF is preferred over QTcB in schizophrenia patients with higher heart rates.

Cardiovasular changes after placement of a classic endotracheal tube, double-lumen tube, and Laryngeal Mask Airway

STUDY OBJECTIVE

To compare hemodynamic responses, P wave dispersion (Pd), and QT dispersion (QTd) after placement of a classic endotracheal tube (ETT), double-lumen tube (DLT), or Laryngeal Mask Airway (LMA).

DESIGN

Prospective study.

SETTING

Outpatient surgery center.

PATIENTS

75 adult, ASA physical status 1 and 2 patients undergoing cystoscopy and thoracoscopic surgery.

INTERVENTIONS

Patients were randomized to undergo placement of an ETT (Group T; n = 25), DLT (Group D; n = 25), or LMA (Group L; n = 25). Anesthesia was induced by etomidate 0.3 mg/kg and fentanyl 1.0 μg/kg, and maintained with nitrous oxide, oxygen, 2% to 3% sevoflurane, and rocuronium 0.5 mg/kg.

MEASUREMENTS

Mean arterial pressure (MAP) and heart rate (HR) were recorded immediately before intubation and after intubation at one, 3, 5, 10,15, 20, 25, and 30 minutes after intubation/airway insertion.

RESULTS

QT dispersion after tube placement was significantly higher than before tube placement in Group D (P = 0.0001) and Group L (P = 0.03). Mean arterial pressure and HR in Group T were significantly higher than in Group L at the first minute after tube placement (P = 0.02). Heart rate and MAP at baseline were significantly higher than the other measurement times in Groups T and D (P < 0.01).

CONCLUSIONS

The LMA caused no change in Pd, HR, or MAP values during or after airway placement, but caused QTd after airway insertion. The ETT caused a sudden increase at the first minute after tube placement, without any Pd or QTd. In addition, DLT caused QTd without any serious change in hemodynamics.

Sex difference in QTc prolongation in chronic institutionalized patients with schizophrenia on long-term treatment with typical and atypical antipsychotics

OBJECTIVE

The rate-corrected electrocardiographic QT (QTc) interval may significantly increase in patients with schizophrenia taking antipsychotics. The objective of this naturalistic study was to assess the prevalence of prolonged QTc interval in a large population of inpatients with chronic schizophrenia and to explore QTc relationship with demographic variables and prescribed treatments.

MATERIALS AND METHODS

Electrocardiograms were obtained from age- and sex-matched 456 controls and 1,006 inpatients with schizophrenia (male/female = 689/317) taking antipsychotics. QTc prolongation was defined as a mean value of two standard deviations above the controls. The adjusted relative risk was calculated using logistic regression analysis.

RESULTS

QTc prolongation was present in 45 (4.5%) of 1,006 patients overall. Fewer men (3.2%, 22 of 689) than women (7.3%, 23 of 317) displayed QTc prolongation (p < 0.004). Moreover, QTc intervals were shorter in male (391 ± 31 ms) than female subjects (400 ± 37 ms) (p < 0.001). Clozapine was found to produce a longer QTc intervals compared to risperidone and typical antipsychotics. Furthermore, multiple regression analysis showed that significant predictors for QTc prolongation were comorbid cardiovascular disease, antipsychotic types, sex, and age (all p < 0.01).

CONCLUSION

Our present findings suggest that there are sex differences in the prevalence of QTc prolongation and QTc lengthening in schizophrenia. Antipsychotic types are risk factors for QTc prolongation, and risks are substantially higher for clozapine.

QTc interval in a sample of long-term schizophrenia inpatients

This naturalistic study attempted to determine the prevalence of prolonged QTc interval in a relatively large population of inpatients hospitalized with chronic schizophrenia, and to explore QTc relationship with demographic variables, metabolic parameters and prescribed treatments. All inpatients from a Spanish long-term psychiatric hospital were cross-sectionally investigated to determine the prevalence of QTc prolongation and metabolic syndrome. The sample with a DSM-IV diagnosis of schizophrenia included 171 Caucasian inpatients, all of Spanish origin. A prolonged QTc interval was defined as >450 ms in men and >470 ms in women. The relationships between QTc and other continuous variables were assessed using a linear regression model with QTc as the dependent variable. Only 10 patients (6%) had a prolonged QTc interval; one case was possibly explained by hypokalemia. Three patients (2%) had a QTc > 500 ms. Gender, old age (> or = 50 years old), current smoking, systolic blood pressure, HDL cholesterol and history of arrhythmia were found to have significant effects on QTc interval in a linear regression analysis. After controlling for significant variables, the mean QTc interval was not significantly influenced by antipsychotic dose, type of antipsychotic treatment, the use of depot antipsychotics, or the number of different antipsychotics prescribed. Our study focused on long-term schizophrenia inpatients with frequent antipsychotic polypharmacy and high antipsychotic doses, and suggested that after excluding the case with hypokalemia length of QTc was associated with history of arrhythmias and with metabolic factors, while the effects of antipsychotic compound or class were not so evident.

QTc dispersion in patients referred for electroconvulsive therapy

OBJECTIVE

To determine the presence of possible risk factors for arrhythmias during electroconvulsive therapy (ECT) by assessing QTc dispersion on the baseline electrocardiogram.

METHOD

The pre-ECT electrocardiogram on 105 patients was examined, and QTc dispersion was calculated. This was correlated with presence or absence of cardiac conditions and various psychotropic medications being used by the patients.

RESULTS

Neither age nor sex was associated with QTc dispersion. Presence of cardiac illness also was not associated with prolongation of QTc dispersion. None of the psychotropic medication classes, including atypical antipsychotics, were associated with prolongation of QTc dispersion either.

CONCLUSION

In patients referred for ECT, baseline QTc dispersion does not correlate with presence of cardiac illness or concomitant psychotropic usage.

Antipsychotic drugs and QTc prolongation: the potential role ofCYP2D6genetic polymorphism

Although the most common, and usually serious, side effects of first-generation (or typical) antipsychotic drugs, such as Parkinsonism, dystonias and tardive dyskinesia, were known from early times, their cardiovascular safety was not properly in the focus of treatment management. The growing evidence of these drug-related cardiac changes and the appearance of potentially fatal dysrhythmias have increased the interest on their safety profile. Thus, the introduction of the new second-generation (atypical) antipsychotic drugs put emphasis on the preregistration evaluation of the potential cardiac side effects and electrocardiogram predictors (QT interval lengthening). In spite of this, these drugs do not appear to be exempt from these potential risks. The present review summarizes up-to-date knowledge about the cardiac safety of antipsychotic drugs, and analyses the role of drug metabolic processes (CYP2D6 genetic polymorphism) in the complex pathophysiology of the phenomenon. In addition, some recommendations are formulated.