Cardiovascular Safety of Hydroxychloroquine-Azithromycin in 424 COVID-19 Patients.

Background and Objectives: Hydroxychloroquine (HCQ) combined with azithromycin (AZM) has been widely administered to patients with COVID-19 despite scientific controversies. In particular, the potential of prolong cardiac repolarization when using this combination has been discussed. Materials and Methods: We report a pragmatic and simple safety approach which we implemented among the first patients treated for COVID-19 in our center in early 2020. Treatment contraindications were the presence of severe structural or electrical heart disease, baseline corrected QT interval (QTc) > 500 ms, hypokalemia, or other drugs prolonging QTc that could not be interrupted. Electrocardiogram and QTc was evaluated at admission and re-evaluated after 48 h of the initial prescription. Results: Among the 424 consecutive adult patients (mean age 46.3 ± 16.1 years; 216 women), 21.5% patients were followed in conventional wards and 78.5% in a day-care unit. A total of 11 patients (2.6%) had contraindications to the HCQ-AZ combination. In the remaining 413 treated patients, there were no arrhythmic events in any patient during the 10-day treatment regimen. QTc was slightly but statistically significantly prolonged by 3.75 ± 25.4 ms after 2 days of treatment (p = 0.003). QTc prolongation was particularly observed in female outpatients <65 years old without cardiovascular disease. Ten patients (2.4%) developed QTc prolongation > 60 ms, and none had QTc > 500 ms. Conclusions: This report does not aim to contribute to knowledge of the efficacy of treating COVID-19 with HCQ-AZ. However, it shows that a simple initial assessment of patient medical history, electrocardiogram (ECG), and kalemia identifies contraindicated patients and enables the safe treatment of COVID-19 patients with HCQ-AZ. QT-prolonging anti-infective drugs can be used safely in acute life-threatening infections, provided that a strict protocol and close collaboration between infectious disease specialists and rhythmologists are applied.

An electrophysiological substrate of COVID-19.

SARS-CoV-2 infection is associated with an increased risk of late cardiovascular (CV) outcomes. However, more data is needed to describe the electrophysiologic (EP) manifestation of post-acute CV sequelae of COVID-19. We compared two cohorts of adult patients with SARS-CoV-2 polymerase chain reaction (PCR) test and an electrocardiogram (ECG) performed between March 1, 2020, and September 13, 2020, in a retrospective double-cohort study, "Cardiovascular Risk Stratification in Covid-19" (CaVaR-Co19; NCT04555187). Patients with positive PCR comprised a COVID-19(+) cohort (n = 41; 61% women; 80% symptomatic), whereas patients with negative tests formed the COVID-19(-) cohort (n = 155; 56% women). In longitudinal analysis, comparing 3 ECGs recorded before, during, and on average 40 days after index COVID-19 episode, after adjustment for demographic and socioeconomic characteristics, baseline CV risk factors and comorbidities, use of prescription medications (including QT-prolonging drugs) before and during index COVID-19 episode, and the longitudinal changes in RR' intervals, heart rhythm, and ventricular conduction type, only in the COVID-19(+) cohort QTc increased by +30.2(95% confidence interval [CI] 0.1-60.3) ms and the spatial ventricular gradient (SVG) elevation increased by +13.5(95%CI 1.2-25.9)°. In contrast, much smaller, statistically nonsignificant changes were observed in the COVID-19(-) cohort. In conclusion, post-acute CV sequelae of SARS-CoV-2 infection manifested on ECG by QTc prolongation and rotation of the SVG vector upward.

Remdesivir (VEKLURY) for Treating COVID-19: Guinea Pig Ex Vivo and In Vivo Cardiac Electrophysiological Effects.

ABSTRACT: Bradycardia and QTc interval prolongation on the ECG have been reported with remdesivir (Veklury), an antiviral drug recently approved for treating severely ill patients with COVID-19. The objective was to evaluate the effects of remdesivir on cardiac electrophysiology ex vivo and in vivo. Ex vivo: Langendorff retroperfusion experiments were performed on isolated hearts from male Hartley guinea pigs (n = 23, total) exposed to either remdesivir 3, 10, or 30 µmol/L to assess drug-induced prolongation of the monophasic action potential duration measured at 90% repolarization (MAPD 90 ). In vivo: ECG recordings using wireless cardiac telemetry were performed in guinea pigs (n = 6) treated with daily i.p. doses of remdesivir 5 mg/kg on day 1 and 2.5 mg/kg on days 2-10. Ex vivo remdesivir (3, 10, and 30 µmol/L) had no statistically significant effect on MAPD 90 , while pacing the hearts at basic stimulation cycle lengths of 200 or 250 milliseconds, or when the hearts were not paced and beating at their intrinsic heart rate. In a second set of similar ex vivo experiments, remdesivir 10 µmol/L did not potentiate the MAPD 90 -prolonging effects of dofetilide 20 nmol/L (n = 4) hearts. In vivo remdesivir caused small but statistically significant prolongations of the RR and QTc F intervals at day 1 (5 mg/kg) and at day 10 (2.5 mg/kg). No ventricular arrhythmias were ever observed under the effect of remdesivir. Remdesivir causes bradycardia, and mild QTc prolongation, which nonetheless, could be of clinical relevance in many hospitalized patients with COVID-19 concomitantly treated with multiple drugs.

An observational, retrospective, comprehensive pharmacovigilance analysis of hydroxychloroquine-associated cardiovascular adverse events in patients with and without COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a global pandemic. Hydroxychloroquine (HCQ)-associated cardiovascular adverse events (CVAEs) have been increasingly reported. AIM: This study aimed to present an observational, retrospective, and comprehensive pharmacovigilance analysis of CVAE associated with HCQ in patients with and without COVID-19 using the US Food and Drug Administration Adverse Events Reporting System (FAERS) data from January 2020 to December 2020. METHOD: We identified 3302 adverse event reports from the FAERS database in the year 2020 and divided them into COVID-19 and non-COVID-19 groups, respectively. Then we analyzed whether there were differences in CVAEs between the two groups. RESULTS: We found that CVAE was higher in cases with COVID-19 compared to those without COVID-19, odds ratio (OR) of 1.26 and a 95% confidence interval (95% CI) of 1.02-1.54. Cases with COVID-19 treated with HCQ exhibited relatively higher proportions of torsade de points (TdP) and QT prolongation (OR 3.10, 95% CI 2.24-4.30), shock-associated TdP (OR 2.93, 95% CI 2.13-4.04), cardiac arrhythmias (OR 2.07, 95% CI 1.60-2.69), cardiac arrhythmia terms (including bradyarrhythmias and tachyarrhythmias) (OR 2.15, 95% CI 1.65-2.80), bradyarrhythmias (including conduction defects and disorders of sinus node function) (OR 2.56, 95% CI 1.86-3.54), and conduction defects (OR 2.56, 95% CI 1.86-3.54). CONCLUSION: Our retrospective observational analysis suggested that the proportion of CVAE associated with HCQ, especially TdP and QT prolongation, was higher in patients with COVID-19. Understanding the effects of COVID-19 on the cardiovascular system is essential to providing comprehensive medical care to patients receiving HCQ treatment.

Revisiting QT prolongation in acute rheumatic fever - Relevance for hydroxychloroquine treatment.

In-vitro evidence suggests hydroxychloroquine could be a potential immunomodulator for the inflammatory carditis of acute rheumatic fever (ARF). Hydroxychloroquine used as an anti-inflammatory agent has a low side effect profile but its use in the Covid-19 pandemic raised concerns about QTc interval prolongation and cardiac arrhythmias. The prolongation of QTc in ARF appears benign but has not been widely studied. We aim to report QTc intervals in a contemporary ARF population and consider implications for hydroxychloroquine use in ARF. The study cohort was 197 children <15 years of age with a clinical diagnosis of ARF. The QTc mean (SD) was 445 msec (28), range 370-545 msec. Eighteen percent of the cohort had a QTc > 99th percentile for normal by age and 8 patients (4%) had a QTc over 500 msec. There was no difference of QTc by age or gender. Inter-observer repeatability for QTc (n = 33) was 35 msec. The QTc is often prolonged in the early phase of ARF, meaning that QT prolonging medications should be used with caution in this setting. Serial ECG monitoring of the QT interval is recommended if hydroxycholoroquine is used in ARF.

Safety profile of hydroxychloroquine used off-label for the treatment of patients with COVID-19: A descriptive study based on EudraVigilance data.

At the beginning of the COVID-19 pandemic, worldwide attempts were made to identify potential drugs effective against the COVID-19. Hydroxychloroquine was among the first receiving attention. However, following its use in therapy, it has been shown that hydroxychloroquine was not only ineffective but probably, due to its known side effects, even responsible of increased mortality of patients. The objective of this study was to review the safety profile of hydroxychloroquine used off-label for the treatment of COVID-19. We analyze the reports of suspected adverse drug reactions (ADRs) collected in EudraVigilance, the European database of ADR reports. We collected 2266 reports for 2019 and 6525 for 2020. The most reported ADRs during 2020 were those relating to cardiac, hepatic, renal toxicity such as QT prolongation with 400 cases in 2020 (of which, 345 cases-9.97%-with COVID-19 as a therapeutic indication) versus 1 case only in 2019 (0.01%), long QT syndrome: 38 cases in 2020 (36 as COVID-19 treatment) versus 0 in 2019, hepatitis: 13 cases in 2019 (0.11%) and 132 in 2020, and 32 cases (24, 0.69%) of acute kidney injury in 2020 and only 3 cases in 2019. Moreover, some important vision-related ADRs also increased significantly during 2020, such as retinal toxicity with 92 cases in 2020 versus 7 in 2019. Even though with its intrinsic limitations, our results may be added to the most recent scientific evidence to confirm the unfavorable risk profile of hydroxychloroquine in its off-label use in the treatment of COVID-19 disease.

Acquired long QT syndrome due to antiemetics, COVID-19 and Blastocystis hominis induced exacerbation of congenital chloride losing diarrhoea.

Congenital chloride losing diarrhoea (CCLD) is a rare disease caused by mutations in an intestinal chloride/bicarbonate ion exchange channel. Few reports describe CCLD in adults and none has described the impact of a parasitic infection on CCLD. Severe diarrhoea may result in hypokalaemia with QT interval prolongation. Treatment with antiemetics may further increase the QT interval. To raise awareness of this preventable complication, we describe the course of a woman in her 20s with CCLD who developed COVID-19 and a Blastocystis hominis infestation. Treatment with antiemetics and hypokalaemia resulted in prolongation of the QT interval to 640 ms. While, the QT interval normalised with discontinuation of antiemetics and electrolyte replacement, patients with CCLD must take precautions to prevent gastrointestinal infections. Regardless, whenever patients with CCLD present to hospital, the authors recommend monitoring the QT interval and avoiding medications that predispose to torsade de pointes.

Hydroxychloroquine cardiotoxicity: a case-control study comparing patients with COVID-19 and patients with systemic lupus erythematosus.

OBJECTIVES: Antimalarials have been associated with QT prolongation in COVID-19 patients but are generally safe in systemic lupus erythematosus (SLE).We compared the prevalence of QTc prolongation between COVID-19 and SLE patients treated with hydroxychloroquine (HCQ). METHODS: We included patients with SARS-CoV-2 infection confirmed by nasopharyngeal swab and patients taking HCQ for SLE. A prolonged QTc was defined as an increase in QTc intervals >60 ms (compared with baseline) or as a QTc of ≥500 ms. We performed the univariate and multivariate logistic regression to investigate the risk factors for QTc prolongation in COVID-19 patients. RESULTS: We enrolled 58 COVID-19 patients (median age 70.5 years, IQR 25), grouped into group A (patients with HCQ) group B (patients with HCQ + azithromycin) and group C (not received either drug). Fifty (26%) COVID-19 patients presented a QTc prolongation (12 QTc≥500 ms, 3 patients ΔQTc>60 ms). We did not find any differences in QTc prolongation among the three treatment groups. Baseline QTc (OR 111.5) and D-dimer (OR 78.3) were independently associated to QTc prolongation. Compared to the 50 SLE patients (median age 38.5 years, IQR 22), chronically treated with HCQ, COVID-19 patients showed significantly longer QTc (p<0.001). CONCLUSIONS: This is the first study demonstrating that, unlike COVID-19 patients, patients with SLE are not susceptible to HCQ-induced long QT syndrome and arrhythmia. The combined arrhythmogenic effect of SARS-CoV-2 infection and HCQ could account for the excess of QTc prolongation and fatal arrhythmias described in patients with COVID-19.

QTc interval prolongation in patients infected with SARS-CoV-2 and treated with antiviral drugs.

INTRODUCTION: Many antiviral agents, such as hydroxychloroquine, have been used to treat COVID-19, without being broadly accepted. QTc prolongation is a worrisome adverse effect, scarcely studied in pediatrics. PATIENTS AND METHODS: Paediatric patients affected from COVID-19 who received antivirals were matched (1:2) with controls not infected nor exposed. Electrocardiograms were prospectively analyzed at baseline, during the first 72 h of treatment and after 72 h. RESULTS: Eleven (22.9%) out of 48 patients admitted due to COVID-19 (March-July 2020) received antiviral therapy. All had underlying diseases: congenital heart disease (4/11; 36.4%) and immunosuppression (3/11; 27.3%) stand out. 5/11 (45.5%) received treatment at baseline with a potential effect on QTc. There where no differences observed in the baseline QTc between cases and controls: 414.8 ms (49.2) vs 416.5 ms (29.4), (P = .716). Baseline long QT was observed in 2/11 cases and 2/22. Among cases, 10/11 (90.9%) received hydroxychloroquine, mainly associated with azithromycin (8/11; 72.7%), 3 received lopinavir/ritonavir and one remdesivir. The median increase in QTc after 72 h under treatment was 28.9 ms [IQR 48.7] (P = .062). 4/11 (36.4%) patients had a long QTc at 72 h, resulting in 3 patients ≥500 ms; treatment was stopped in one (QTc 510 ms) but ventricular arrhythmias were not documented. CONCLUSIONS: The use of antivirals caused an increase on the QTc interval after 72 h of treatment, being the QTc long in 36.3% of the patients, although no arrhythmic events were observed. The use of hydroxychloroquine and antivirals requires active QTc monitoring and it is recommended to discontinue treatment if QTc > 500 ms.

Transient Hypogonadism Is Associated With Heart Rate-Corrected QT Prolongation and Torsades de Pointes Risk During Active Systemic Inflammation in Men.

Background Systemic inflammation and male hypogonadism are 2 increasingly recognized "nonconventional" risk factors for long-QT syndrome and torsades de pointes (TdP). Specifically, inflammatory cytokines prolong, while testosterone shortens the heart rate-corrected QT interval (QTc) via direct electrophysiological effects on cardiomyocytes. Moreover, several studies demonstrated important interplays between inflammation and reduced gonad function in men. We hypothesized that, during inflammatory activation in men, testosterone levels decrease and that this enhances TdP risk by contributing to the overall prolonging effect of inflammation on QTc. Methods and Results We investigated (1) the levels of sex hormones and their relationship with inflammatory markers and QTc in male patients with different types of inflammatory diseases, during active phase and recovery; and (2) the association between inflammatory markers and sex hormones in a cohort of male patients who developed extreme QTc prolongation and TdP, consecutively collected over 10 years. In men with active inflammatory diseases, testosterone levels were significantly reduced, but promptly normalized in association with the decrease in C-reactive protein and interleukin-6 levels. Reduction of testosterone levels, which also inversely correlated with 17-ß estradiol over time, significantly contributed to inflammation-induced QTc prolongation. In men with TdP, both active systemic inflammation and hypogonadism were frequently present, with significant correlations between C-reactive protein, testosterone, and 17-ß estradiol levels; in these patients, increased C-reactive protein and reduced testosterone were associated with a worse short-term outcome of the arrhythmia. Conclusions During systemic inflammatory activation, interleukin-6 elevation is associated with reduced testosterone levels in males, possibly deriving from an enhanced androgen-to-estrogen conversion. While transient, inflammatory hypotestosteronemia is significantly associated with an increased long-QT syndrome/TdP risk in men.

Comparative study of the adverse event profile of hydroxychloroquine before and during the Sars-CoV2 pandemic.

AIMS: At the beginning of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, there were no clinically-tested medications for the effective treatment of coronavirus disease. In this context, on 5 March 2020, the French Public Health Council issued several recommendations for the therapeutic management of this new disease, including the use of hydroxychloroquine (HCQ). An unexpected cardiovascular safety signal was quickly identified as being more frequent than expected thanks to the reports of adverse drug reactions (ADRs) submitted to French regional pharmacovigilance centres (RPVC). The objective of this study was to compare all ADRs reported with HCQ used in its usual indication, collected before the pandemic period (1985 to 31 December, 2019) with those reported with the coronavirus disease 2019 (COVID-19) indication (1 January to 21 July, 2020). METHODS: For this purpose, reports were extracted from the French pharmacovigilance database and analysed for these two periods. RESULTS: Our study showed a different safety profile in COVID-19 patients with more cardiac disorders (57% of ADRs versus 5% before the pandemic period), especially QT interval prolongation, resulting from an interaction with azithromycin in more than 20% of cases. Hepatobiliary disorders were also significantly more frequent. CONCLUSIONS: These observations could be associated with the effect of the virus itself on the various organs, the profile of the patients treated, and concomitant drug treatments.

Off-Label Use of Hydroxychloroquine in COVID-19: Analysis of Reports of Suspected Adverse Reactions From the Italian National Network of Pharmacovigilance.

This study aimed to characterize adverse drug reactions (ADRs) to hydroxychloroquine in the setting of COVID-19, occurring in Italy in the period March to May 2020. The analysis of the combination therapy with azithromycin or/and lopinavir/ritonavir as well as a comparison with ADRs reported throughout 2019 was performed. ADRs collected by the Italian National Network of Pharmacovigilance were analyzed for their incidence, seriousness, outcome, coadministered drugs, and Medical Dictionary for Regulatory Activities classification. A total of 306 reports were gathered for the quarter of 2020: 54% nonserious and 46% serious, and half of the latter required either the hospitalization or its prolongation. However, most of them were either completely recovered (26%) or in the process of recovery (45%), except for 9 fatal cases. Throughout 2019, 38 reports were collected, 53% nonserious and 47% serious, but no deaths had been reported. Diarrhea, prolonged QT interval, and hypertransaminasemia were the most frequently ADRs reported in 2020, significantly higher than 2019 and specific for COVID-19 subjects treated with hydroxychloroquine. The logistic regression analyses demonstrated that the likelihood of serious ADRs, QT prolongation, and diarrhea significantly increased with hydroxychloroquine dosage. Coadministration of lopinavir/ritonavir and hydroxychloroquine showed a positive correlation with diarrhea and hypertransaminasemia and a negative relationship with the ADR seriousness. The combination therapy with azithromycin was another independent predictor of a serious ADR. Off-label use of hydroxychloroquine for COVID-19, alone or in combination regimens, was associated with increased incidence and/or seriousness of specific ADRs in patients with additional risk factors caused by the infection.

Effects of hydroxychloroquine and its metabolites in patients with connective tissue diseases.

Hydroxychloroquine has attracted attention in the treatment of COVID-19. Many conflicting findings have been reported regarding the efficacy and safety of this drug, which has been used safely in the rheumatological diseases for years. However, these studies lacked measurement methods that allow accurate assessment of hydroxychloroquine and its metabolite levels. The aim of this study was to measure hydroxychloroquine and its metabolite levels in whole blood samples of patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjogren's syndrome (SS) and scleroderma (Scl) by a robust, simple and accurate validated tandem mass spectrometric method, and to investigate the relationship between these levels with drug-related adverse effects and disease activity scores. The validated LC-MS/MS method was applied to measure blood hydroxychloroquine and its metabolite levels of patients with RA, SLE, SS, Scl. Various haematological and biochemical parameters were measured with Beckman-Coulter AU 5800 and Beckman Coulter LH 780 analyzers, respectively. QTc intervals were calculated with Bazett's formula, and the patients were followed up by clinicians in terms of clinical findings and adverse effects. Hydroxychloroquine levels of patients were similar to previous studies. There was a negative correlation between disease activity scores and hydroxychloroquine levels, while the highest correlation was between QTc interval, creatinine and GFR levels with desethylchloroquine. Bidetylchloroquine had the highest correlation with RBC count and liver function tests. Our findings showed that hydroxychloroquine and its metabolite levels were associated with disease activity scores, renal, hepatic function, QTc prolongation, and hematological parameters.

A short focus, azithromycin in the treatment of respiratory viral infection COVID-19: efficacy or inefficacy?

Azithromycin is a macrolide antibiotic. Recent evidence has demonstrated in vitro activity against a wide variety of respiratory tract viruses, including SARS-CoV-2 responsible for the current global pandemic COVID-19. A mechanism of action acting on different phases of the viral cycle is assumed. In addition to its in vitro antiviral properties, some evidence also suggests immunomodulatory and antifibrotic activity. These properties of azithromycin could be useful in the treatment of viral respiratory tract infections such as COVID-19. However, clinical data on the antiviral efficacy of azithromycin in the treatment of respiratory tract infections are inconsistent, both when used as monotherapy and in polypharmacological combination. In addition, cases of azithromycin-induced QT long and malignant arrhythmias are reported. In this short review, we attempt to determine the role of azithromycin in the treatment of viral respiratory tract infections such as COVID-19, therapeutic efficacy, or inefficacy?

Corrected QT interval in hospitalized patients with coronavirus disease 2019: Focus on drugs therapy.

ABSTRACT: Corrected QT (QTc) interval prolongation has been associated with poor patient prognosis. In this study, we assessed the effects of different drugs and cardiac injury on QTc interval prolongation in patients with coronavirus disease 2019 (COVID-19).The study cohort consisted of 395 confirmed COVID-19 cases from the Wuhan Union Hospital West Campus. All hospitalized patients were treated with chloroquine/hydroxychloroquine (CQ/HCQ), lopinavir/ritonavir (LPV/r), quinolones, interferon, Arbidol, or Qingfei Paidu decoction (QPD) and received at least 1 electrocardiogram after drug administration.Fifty one (12.9%) patients exhibited QTc prolongation (QTc ≥ 470 ms). QTc interval prolongation was associated with COVID-19 severity and mortality (both P < .001). Administration of CQ/HCQ (odds ratio [OR], 2.759; 95% confidence interval [CI], 1.318-5.775; P = .007), LPV/r (OR, 2.342; 95% CI, 1.152-4.760; P = .019), and quinolones (OR, 2.268; 95% CI, 1.171-4.392; P = .015) increased the risk of QTc prolongation. In contrast, the administration of Arbidol, interferon, or QPD did not increase the risk of QTc prolongation. Notably, patients treated with QPD had a shorter QTc duration than those without QPD treatment (412.10 [384.39-433.77] vs 420.86 [388.19-459.58]; P = .042). The QTc interval was positively correlated with the levels of cardiac biomarkers (creatine kinase-MB fraction [rho = 0.14, P = .016], high-sensitivity troponin I [rho = .22, P < .001], and B-type natriuretic peptide [rho = 0.27, P < .001]).In conclusion, QTc prolongation was associated with COVID-19 severity and mortality. The risk of QTc prolongation was higher in patients receiving CQ/HCQ, LPV/r, and quinolones. QPD had less significant effects on QTc prolongation than other antiviral agents.

Arrhythmogenic Risk and Mechanisms of QT-Prolonging Drugs to Treat COVID-19.

While looking for a solution to treat COVID-19, the massive off-label use of several drugs in COVID-19 has generated concerns in the early phase of the pandemic because of possible arrhythmogenic effects in relation to QTc interval prolongation. Indeed, some of these drugs have been historically associated with QT prolongation and Torsade de Point, a potentially lethal ventricular arrhythmia, and their first-time use on a very large scale has raised several concerns in the scientific community. This work aims to summarize the underlying arrhythmogenic mechanisms related to the use of potentially QT-prolonging drugs used during the pandemic to treat COVID-19.

The cardiovascular effects of amodiaquine and structurally related antimalarials: An individual patient data meta-analysis.

BACKGROUND: Amodiaquine is a 4-aminoquinoline antimalarial similar to chloroquine that is used extensively for the treatment and prevention of malaria. Data on the cardiovascular effects of amodiaquine are scarce, although transient effects on cardiac electrophysiology (electrocardiographic QT interval prolongation and sinus bradycardia) have been observed. We conducted an individual patient data meta-analysis to characterise the cardiovascular effects of amodiaquine and thereby support development of risk minimisation measures to improve the safety of this important antimalarial. METHODS AND FINDINGS: Studies of amodiaquine for the treatment or prevention of malaria were identified from a systematic review. Heart rates and QT intervals with study-specific heart rate correction (QTcS) were compared within studies and individual patient data pooled for multivariable linear mixed effects regression. The meta-analysis included 2,681 patients from 4 randomised controlled trials evaluating artemisinin-based combination therapies (ACTs) containing amodiaquine (n = 725), lumefantrine (n = 499), piperaquine (n = 716), and pyronaridine (n = 566), as well as monotherapy with chloroquine (n = 175) for uncomplicated malaria. Amodiaquine prolonged QTcS (mean = 16.9 ms, 95% CI: 15.0 to 18.8) less than chloroquine (21.9 ms, 18.3 to 25.6, p = 0.0069) and piperaquine (19.2 ms, 15.8 to 20.5, p = 0.0495), but more than lumefantrine (5.6 ms, 2.9 to 8.2, p < 0.001) and pyronaridine (-1.2 ms, -3.6 to +1.3, p < 0.001). In individuals aged ≥12 years, amodiaquine reduced heart rate (mean reduction = 15.2 beats per minute [bpm], 95% CI: 13.4 to 17.0) more than piperaquine (10.5 bpm, 7.7 to 13.3, p = 0.0013), lumefantrine (9.3 bpm, 6.4 to 12.2, p < 0.001), pyronaridine (6.6 bpm, 4.0 to 9.3, p < 0.001), and chloroquine (5.9 bpm, 3.2 to 8.5, p < 0.001) and was associated with a higher risk of potentially symptomatic sinus bradycardia (≤50 bpm) than lumefantrine (risk difference: 14.8%, 95% CI: 5.4 to 24.3, p = 0.0021) and chloroquine (risk difference: 8.0%, 95% CI: 4.0 to 12.0, p < 0.001). The effect of amodiaquine on the heart rate of children aged <12 years compared with other antimalarials was not clinically significant. Study limitations include the unavailability of individual patient-level adverse event data for most included participants, but no serious complications were documented. CONCLUSIONS: While caution is advised in the use of amodiaquine in patients aged ≥12 years with concomitant use of heart rate-reducing medications, serious cardiac conduction disorders, or risk factors for torsade de pointes, there have been no serious cardiovascular events reported after amodiaquine in widespread use over 7 decades. Amodiaquine and structurally related antimalarials in the World Health Organization (WHO)-recommended dose regimens alone or in ACTs are safe for the treatment and prevention of malaria.