The risk of QTc-interval prolongation in COVID-19 patients treated with chloroquine

Affinity binding of COVID-19 drug candidates (chloroquine/hydroxychloroquine) and serum albumin: Based on photochemistry and molecular docking

Chloroquine (CQ) and hydroxychloroquine (HCQ) show good efficacy in the treatment of SARS-CoV-2 in the early stage, while they are no longer recommended due to their side effects. As an important drug delivery carrier, serum albumin (SA) is closely related to the efficacy of drugs. Here, the affinity behaviour of chloroquine and hydroxychloroquine with two SA were investigated through the multispectral method of biochemistry and computer simulation. The results showed that the intrinsic emission of both SA was quenched by CQ and HCQ in a spontaneous exothermic entropy reduction static process, which relied mainly on hydrogen bonding and van der Waals forces. The lower binding constants suggested weak binding between the two drugs and SA, which might lead to differences in efficacy and possibly even to varying side effects. Binding site recognition demonstrated that CQ preferred to bind to the two sites of both SA, while HCQ tended to bind to site I of SA. The results of conformational studies demonstrated that CQ and HCQ could affect the structure of both SA by slightly increasing the α-helix content of SA. Finally, we combine the results from experimental start with molecular simulations to suggest drug modifications to guide the design of drugs. This work has important implications for guiding drug design improvements to select CQ derivatives with fewer side effects for the treatment of COVID-19.

ESC guidance for the diagnosis and management of cardiovascular disease during the COVID-19 pandemic: part 2-care pathways, treatment, and follow-up

AIMS

Since its emergence in early 2020, the novel severe acute respiratory syndrome coronavirus 2 causing coronavirus disease 2019 (COVID-19) has reached pandemic levels, and there have been repeated outbreaks across the globe. The aim of this two part series is to provide practical knowledge and guidance to aid clinicians in the diagnosis and management of cardiovascular (CV) disease in association with COVID-19.

METHODS AND RESULTS

A narrative literature review of the available evidence has been performed, and the resulting information has been organized into two parts. The first, which was reported previously, focused on the epidemiology, pathophysiology, and diagnosis of CV conditions that may be manifest in patients with COVID-19. This second part addresses the topics of: care pathways and triage systems and management and treatment pathways, both of the most commonly encountered CV conditions and of COVID-19; and information that may be considered useful to help patients with CV disease (CVD) to avoid exposure to COVID-19.

CONCLUSION

This comprehensive review is not a formal guideline but rather a document that provides a summary of current knowledge and guidance to practicing clinicians managing patients with CVD and COVID-19. The recommendations are mainly the result of observations and personal experience from healthcare providers. Therefore, the information provided here may be subject to change with increasing knowledge, evidence from prospective studies, and changes in the pandemic. Likewise, the guidance provided in the document should not interfere with recommendations provided by local and national healthcare authorities.

ESC guidance for the diagnosis and management of cardiovascular disease during the COVID-19 pandemic: part 2-care pathways, treatment, and follow-up

AIMS

Since its emergence in early 2020, the novel severe acute respiratory syndrome coronavirus 2 causing coronavirus disease 2019 (COVID-19) has reached pandemic levels, and there have been repeated outbreaks across the globe. The aim of this two part series is to provide practical knowledge and guidance to aid clinicians in the diagnosis and management of cardiovascular (CV) disease in association with COVID-19.

METHODS AND RESULTS

A narrative literature review of the available evidence has been performed, and the resulting information has been organized into two parts. The first, which was reported previously, focused on the epidemiology, pathophysiology, and diagnosis of CV conditions that may be manifest in patients with COVID-19. This second part addresses the topics of: care pathways and triage systems and management and treatment pathways, both of the most commonly encountered CV conditions and of COVID-19; and information that may be considered useful to help patients with CV disease (CVD) to avoid exposure to COVID-19.

CONCLUSION

This comprehensive review is not a formal guideline but rather a document that provides a summary of current knowledge and guidance to practicing clinicians managing patients with CVD and COVID-19. The recommendations are mainly the result of observations and personal experience from healthcare providers. Therefore, the information provided here may be subject to change with increasing knowledge, evidence from prospective studies, and changes in the pandemic. Likewise, the guidance provided in the document should not interfere with recommendations provided by local and national healthcare authorities.

Hydroxychloroquine alone or in combination with azithromycin and corrected QT prolongation in COVID-19 patients: A systematic review

BACKGROUND

Despite the controversies about the effectiveness of the current drug regimens for coronavirus disease 2019 (COVID-19), these drugs are still the only options available. Moreover, the safety of these drugs is yet to be confirmed. A serious concern is the occurrence of various cardiac arrhythmias, particularly QT prolongation.

AIM

To summarize the incidence and estimate the risk of QT interval prolongation in patients scheduling for conventional treatment (hydroxychloroquine alone or in combination with azithromycin) for COVID-19.

METHODS

We comprehensively searched Medline, Web of Knowledge, Google Scholar, Scopus, and Cochrane Central Register of Controlled Trials databases until October 31, 2020 for all eligible studies under the considered keywords COVID-19, arrhythmia, QT interval, therapy, azithromycin, and hydroxychloroquine until. The study protocols were established in compliance with PRISMA-P guidelines (Preferred Reporting Items for Systematic Review and Meta-Analysis – Protocols), and a nine-star Newcastle-Ottawa Scale scoring system was used to assess the methodological quality of all eligible studies. Outcome measures were corrected QT (QTc) prolongation, cardiac arrhythmias, or sudden cardiac death.

RESULTS

Fifteen studies enrolling 8298 patients with targeted COVID-19 therapeutic regimes were included. The eligible studies found a significant increase in the mean QTc interval following treatment with the described medications compared to baseline QTc with weighted standard differences in means of 0.766. The pooled prevalence rate of QTc prolongation was estimated to be 9.2% (95% confidence interval: 4.5% to 18.1%).

CONCLUSION

Hydroxychloroquine ± azithromycin regimen can significantly increase the risk of developing QTc prolongation.

Prolonged corrected QT interval in hospitalized patients with coronavirus disease 2019 in Dubai, United Arab Emirates: a single-center, retrospective study

OBJECTIVE

To evaluate the association of a prolonged corrected QT (QTc) interval in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and its association with in-patient mortality.

METHODS

A cohort of 745 patients were recruited from a single center between 1 March 2020 and 31 May 2020. We analyzed the factors associated with a prolonged QTc and mortality.

RESULTS

A prolonged QTc interval >450 ms was found in 27% of patients admitted with SARS-CoV-2 infection. These patients were predominantly older, on a ventilator, and had hypertension, diabetes mellitus, or ischemic heart disease. They also had high troponin and D-dimer concentrations. A prolonged QTc interval had a significant association with the requirement of ventilator support and was associated with an increased odds of mortality. Patients who died were older than 55 years, and had high troponin, D-dimer, creatinine, procalcitonin, and ferritin concentrations, a high white blood cell count, and abnormal potassium concentrations (hypo- or hyperkalemia).

CONCLUSIONS

A prolonged QTc interval is common in patients with SARS-CoV-2 infection and it is associated with worse outcomes. Older individuals and those with comorbidities should have an electrocardiogram performed, which is noninvasive and easily available, on admission to hospital to identify high-risk patients.

Electrocardiographic Manifestations in Patients with COVID-19: Daegu in South Korea

As COVID-19 spreads worldwide, cardiac injury in patients infected with COVID-19 becomes a significant concern. Thus, this study investigates the impact of several electrocardiogram parameters and disease severity in COVID-19 patients. The deceased patients showed increased dispersion of QTc and Tpe-c compared with surviving patients (78.2±41.1 vs. 40.8±24.6 ms and 60.2±37.3 vs 40.8±24.5 ms, both p<0.05). The QTc dispersion of more than 56.1 ms could predict the mortality in multivariate analysis (Odd ratio 8.06, 95% Confidence Interval 2.843–25.750). A prolonged QTc dispersion could be an independent predictable factor of mortality.

Background and Objectives

As the coronavirus disease 2019 (COVID-19) spreads worldwide, cardiac injury in patients infected with COVID-19 becomes a significant concern. Thus, this study investigates the impact of several electrocardiogram (ECG) parameters and disease severity in COVID-19 patients.

Methods

Seven medical centers in Daegu admitted 822 patients with COVID-19 between February and April 2020. This study examined 267 patients among them who underwent an ECG test and evaluated their biochemical parameters like C-reactive protein (CRP), log N-terminal pro-B-type Natriuretic Peptide (NT-proBNP), cardiac enzyme, and ECG parameters (heart rate, PR interval, QRS interval, T inversion, QT interval, and Tpe [the interval between peak to end in a T wave]).

Results

Those patients were divided into 3 groups of mild (100 patients), moderate (89 patients), and severe (78 patients) according to clinical severity score. The level of CRP, log NT-proBNP, and creatinine kinase-myocardial band were significantly increased in severe patients. Meanwhile, severe patients exhibited prolonged QT intervals (QTc) and Tpe (Tpe-c) compared to mild or moderate patients. Moreover, deceased patients (58; 21.7%) showed increased dispersion of QTc and Tpe-c compared with surviving patients (78.2±41.1 vs. 40.8±24.6 ms and 60.2±37.3 vs. 40.8±24.5 ms, both p<0.05, respectively). The QTc dispersion of more than 56.1 ms could predict the mortality in multivariate analysis (odd ratio, 11.55; 95% confidence interval, 3.746–42.306).

Conclusions

COVID-19 infections could involve cardiac injuries, especially cardiac repolarization abnormalities. A prolonged QTc dispersion could be an independent predictable factor of mortality.

No difference in biomarkers of ischemic heart injury and heart failure in patients with COVID-19 who received treatment with chloroquine phosphate and those who did not

Background

Chloroquine was promoted as a COVID-19 therapeutic early in the pandemic. Most countries have since discontinued the use of chloroquine due to lack of evidence of any benefit and the risk of severe adverse events. The primary aim of this study was to examine if administering chloroquine during COVID-19 imposed an increased risk of ischemic heart injury or heart failure.

Methods

Medical records, laboratory findings, and electrocardiograms of patients with COVID-19 who were treated with 500 mg chloroquine phosphate daily and controls not treated with chloroquine were reviewed retrospectively. Controls were matched in age and severity of disease.

Results

We included 20 patients receiving chloroquine (500 mg twice daily) for an average of five days, and 40 controls. The groups were comparable regarding demographics and biochemical analyses including C-reactive protein, thrombocytes, and creatinine. There were no statistically significant differences in cardiac biomarkers or in electrocardiograms. Median troponin T was 10,8 ng/L in the study group and 17.9 ng/L in the control group, whereas median NT-proBNP was 399 ng/L in patients receiving chloroquine and 349 ng/L in the controls.

Conclusions

We found no increased risk of ischemic heart injury or heart failure as a result of administering chloroquine. However, the use of chloroquine to treat COVID-19 outside of clinical trials is not recommended, considering the lack of evidence of its effectiveness, as well as the elevated risk of fatal arrythmias.

Effect of Hydroxychloroquine on QTc in Patients Diagnosed with COVID-19: A Systematic Review and Meta-Analysis

BACKGROUND

Hydroxychloroquine or chloroquine with or without the concomitant use of azithromycin have been widely used to treat patients with SARS-CoV-2 infection, based on early in vitro studies, despite their potential to prolong the QTc interval of patients.

OBJECTIVE

This is a systematic review and metanalysis designed to assess the effect of hydroxychloroquine with or without the addition of azithromycin on the QTc of hospitalized patients with COVID-19.

MATERIALS AND METHODS

PubMed, Scopus, Cochrane and MedRxiv databases were reviewed. A random effect model meta-analysis was used, and I-square was used to assess the heterogeneity. The prespecified endpoints were ΔQTc, QTc prolongation > 500 ms and ΔQTc > 60 ms.

RESULTS

A total of 18 studies and 7179 patients met the inclusion criteria and were included in this systematic review and meta-analysis. The use of hydroxychloroquine with or without the addition of azithromycin was associated with increased QTc when used as part of the management of patients with SARS-CoV-2 infection. The combination therapy with hydroxychloroquine plus azithromycin was also associated with statistically significant increases in QTc. Moreover, the use of hydroxychloroquine alone, azithromycin alone, or the combination of the two was associated with increased numbers of patients that developed QTc prolongation > 500 ms.

CONCLUSION

This systematic review and metanalysis revealed that the use of hydroxychloroquine alone or in conjunction with azithromycin was linked to an increase in the QTc interval of hospitalized patients with SARS-CoV-2 infection that received these agents.

QTc prolongation in COVID-19 patients treated with hydroxychloroquine, chloroquine, azithromycin, or lopinavir/ritonavir: A systematic review and meta-analysis

Purpose

Hydroxychloroquine, chloroquine, azithromycin, and lopinavir/ritonavir are drugs that were used for the treatment of coronavirus disease 2019 (COVID‐19) during the early pandemic period. It is well‐known that these agents can prolong the QTc interval and potentially induce Torsades de Pointes (TdP). We aim to assess the prevalence and risk of QTc prolongation and arrhythmic events in COVID‐19 patients treated with these drugs.

Methods

We searched electronic databases from inception to September 30, 2020 for studies reporting peak QTc ≥500 ms, peak QTc change ≥60 ms, peak QTc interval, peak change of QTc interval, ventricular arrhythmias, TdP, sudden cardiac death, or atrioventricular block (AVB). All meta‐analyses were conducted using a random‐effects model.

Results

Forty‐seven studies (three case series, 35 cohorts, and nine randomized controlled trials [RCTs]) involving 13 087 patients were included. The pooled prevalence of peak QTc ≥500 ms was 9% (95% confidence interval [95%CI], 3%–18%) and 8% (95%CI, 3%–14%) in patients who received hydroxychloroquine/chloroquine alone or in combination with azithromycin, respectively. Likewise, the use of hydroxychloroquine (risk ratio [RR], 2.68; 95%CI, 1.56–4.60) and hydroxychloroquine + azithromycin (RR, 3.28; 95%CI, 1.16–9.30) was associated with an increased risk of QTc prolongation compared to no treatment. Ventricular arrhythmias, TdP, sudden cardiac death, and AVB were reported in <1% of patients across treatment groups. The only two studies that reported individual data of lopinavir/ritonavir found no cases of QTc prolongation.

Conclusions

COVID‐19 patients treated with hydroxychloroquine/chloroquine with or without azithromycin had a relatively high prevalence and risk of QTc prolongation. However, the prevalence of arrhythmic events was very low, probably due to underreporting. The limited information about lopinavir/ritonavir showed that it does not prolong the QTc interval.

COVID-19 pandemic: Can zinc supplementation provide an additional shield against the infection?

Coronavirus disease-19 (COVID-19)-induced severe acute respiratory syndrome is a global pandemic. As a preventive measure, human movement is restricted in most of the world. The Centers for Disease Control and Prevention (CDC), the National Institutes of Health (NIH), along with the World Health Organization (WHO) have laid out some therapeutic guidelines for the infected patients. However, other than handwashing and vigilance surrounding commonly encountered oronasal symptoms and fever, no universally available prophylactic measure has yet been established. In a pandemic, the accessibility of a prophylactic biologically active substance is crucial. Ideally, it would be something readily available at a low price to a larger percentage of the population with minimal risk. Studies have demonstrated that zinc may reduce viral replication and increase immune responses. While consuming zinc (within the recommended upper safety limits), as a prophylactic might provide an additional shield against the initiation and progression of COVID-19 would need clinical studies, the potential clearly exists. Even after vaccination, low zinc status may affect the vaccination responses.

Chloroquine and hydroxychloroquine for COVID-19: Perspectives on their failure in repurposing

WHAT IS KNOWN AND OBJECTIVE

Non-clinical studies suggest that chloroquine (CQ) and hydroxychloroquine (HCQ) have antiviral activities. Early clinical reports of successful HCQ-associated reduction in viral load from small studies in COVID-19 patients spurred a large number of national and international clinical trials to test their therapeutic potential. The objective of this review is to summarize the current evidence on the safety and efficacy of these two agents and to provide a perspective on why their repurposing has hitherto failed.

METHODS

Published studies and rapidly emerging data were reviewed to gather evidence on safety and efficacy of CQ and HCQ in patients with COVID-19 infection or as prophylaxis. The focus is on clinically relevant efficacy endpoints and their adverse effects on QT interval.

RESULTS AND DISCUSSION

At the doses used, the two agents, given alone or with azithromycin (AZM), are not effective in COVID-19 infection. The choice of (typically subtherapeutic) dosing regimens, influenced partly by "QT-phobia," varied widely and seems anecdotal without any pharmacologically reliable supporting clinical evidence. A substantial proportion of patients receiving CQ/HCQ/AZM regimen developed QTc interval prolongation, many with absolute QTc interval exceeding the potential proarrhythmic threshold, but very few developed proarrhythmia.

WHAT IS NEW AND CONCLUSION

The strategy to repurpose CQ/HCQ to combat COVID-19 infection is overshadowed by concerns about their QT liability, resulting in choice of potentially subtherapeutic doses. Although the risk of QT-related proarrhythmia is real, it is low and manageable by careful monitoring. Recent discontinuation of HCQ from at least four large studies effectively marks the end of efforts at repurposing of CQ or HCQ for COVID-19 infection. This episode leaves behind important questions on dose selection and risk/benefit balance in repurposing drugs generally.

COVID-19, hydroxychloroquine and sudden cardiac death: implications for clinical practice in patients with rheumatic diseases

Sudden cardiac death is commonly seen due to arrhythmias, which is a common cardiac manifestation seen in COVID-19 patients, especially those with underlying cardiovascular disease (CVD). Administration of hydroxychloroquine (HCQ) as a potential treatment option during SARS-CoV-2, initially gained popularity, but later, its safe usage became questionable due to its cardiovascular safety, largely stemming from instances of cardiac arrhythmias in COVID-19. Moreover, in the setting of rheumatic diseases, in which patients are usually on HCQ for their primary disease, there is a need to scale the merits and demerits of HCQ usage for the treatment of COVID-19. In this narrative review, we aim to address the association between usage of HCQ and sudden cardiac death in COVID-19 patients. MEDLINE, EMBASE, ClinicalTrials.gov and SCOPUS databases were used to review articles in English ranging from case reports, case series, letter to editors, systematic reviews, narrative reviews, observational studies and randomized control trials. HCQ is a potential cause of sudden cardiac death in COVID-19 patients. As opposed to the reduction in CVD with HCQ in treatment of systemic lupus erythematous, rheumatoid arthritis, and other rheumatic diseases, safe usage of HCQ in COVID-19 patients is unclear; whereby, it is observed to result in QTc prolongation and Torsades de pointes even in patients with no underlying cardiovascular comorbidity. This is occasionally associated with sudden cardiac death or cardiac arrest; hence, its clinical efficacy needs further investigation by large-scale clinical trials.

Reviews on Biological Activity, Clinical Trial and Synthesis Progress of Small Molecules for the Treatment of COVID-19

COVID-19 has broken out rapidly in nearly all countries worldwide, and has blossomed into a pandemic. Since the beginning of the spread of COVID-19, many scientists have been cooperating to study a vast array of old drugs and new clinical trial drugs to discover potent drugs with anti-COVID-19 activity, including antiviral drugs, antimalarial drugs, immunosuppressants, Chinese medicines, Mpro inhibitors, JAK inhibitors, etc. The most commonly used drugs are antiviral compounds, antimalarial drugs and JAK inhibitors. In this review, we summarize mainly the antimalarial drugs chloroquine and hydroxychloroquine, the antiviral drugs Favipiravir and Remdesivir, and JAK inhibitor Ruxolitinib, discussing their biological activities, clinical trials and synthesis progress.

Comparing of the First Electrocardiographic Variables in Patients with Newly Diagnosed COVID-19 with Healthy Men Volunteer: A Systematic Review and Meta-Analysis

Background:

We aimed to report the findings of the first Electrocardiography (ECG), before therapy initiation and receiving medication in COVID-19 patients, and to compare them with the ECG findings of healthy men.

Methods:

A comprehensive and regular search was performed through the keywords (“Electrocardiographic” OR “ECG” OR; “COVID-19” OR “Coronavirus Disease 2019”) without time and language restrictions in the Web of Science, Scopus, ProQuest, Cochrane Library, Science Direct, Medline, PubMed and Google Scholar. After evaluating the quality and reviewing the biases, 27 studies were finally enrolled.

Results:

In 27 studies with a total number of 3994 COVID-19 patients, and mean age of 62.7 yr, 1993 subjects were male. The most common type of arrhythmia in them, especially in severe and critical cases, was 7% based on 10 studies (Atrial Fibrillation); while in 7 studies, QTc interval prolong (≥ 460 msec) was 15% and in 5 studies, QTc interval prolong (≥ 500 msec) was 18%. In COVID-19 patients at the time of admission and healthy men, HR (b per / min) was 85, 61.7 and PR interval (msec) was 285.4, 156 and QRS duration (msec) was 95, 94.3 and QT (msec) was 380. 384.1 and QTc (msec) (Bazett’s formula) was 437, 387.1, respectively. In most cases, the variables were higher for COVID-19 patients.

Conclusion:

ECG abnormalities at the time of admission and prior to the initiation of medication that cause arrhythmic may have a clinically substantial effect on the course of the disease and confirm the effect of COVID-19 on increased cardiovascular risk in long-term.

QTc Prolongation in COVID-19 Patients Using Chloroquine

Chloroquine is used in the treatment of patients with COVID-19 infection, although there is no substantial evidence for a beneficial effect. Chloroquine is known to prolong the QRS and QTc interval on the ECG. To assess the effect of chloroquine on QRS and QTc intervals in COVID-19 patients, we included all inpatients treated with chloroquine for COVID-19 in the Spaarne Gasthuis (Haarlem/Hoofddorp, the Netherlands) and had an ECG performed both in the 72 h before and during or at least 48 h after treatment. We analyzed the (change in) QRS and QTc interval using the one-sample t-test. Of the 106 patients treated with chloroquine, 70 met the inclusion criteria. The average change in QRS interval was 6.0 ms (95% CI 3.3–8.7) and the average change in QTc interval was 32.6 ms (95% CI 24.9–40.2) corrected with the Bazett’s formula and 38.1 ms (95% CI 30.4–45.9) corrected with the Fridericia’s formula. In 19 of the 70 patients (27%), the QTc interval was above 500 ms after start of chloroquine treatment or the change in QTc interval was more than 60 ms. A heart rate above 90 bpm, renal dysfunction, and a QTc interval below 450 ms were risk factors for QTc interval prolongation. Chloroquine prolongs the QTc interval in a substantial number of patients, potentially causing rhythm disturbances. Since there is no substantial evidence for a beneficial effect of chloroquine, these results discourage its use in COVID-19 patients.

Dutch cardiology residents and the COVID-19 pandemic: Every little thing counts in a crisis

The COVID-19 pandemic has overwhelmed healthcare systems worldwide, and a large part of regular cardiology care came to a quick halt. A Dutch nationwide survey showed that 41% of cardiology residents suspended their training and worked at COVID-19 cohort units for up to 3 months. With tremendous flexibility, on-call schedules were altered and additional training was provided in order for residents to be directly available where needed most. These unprecedented times have taught them important lessons on crisis management. The momentum is used to incorporate novel tools for patient care. Moreover, their experience of pandemic and crisis management has provided future cardiologists with unique skills. This crisis will not be wasted; however, several challenges have to be overcome in the near future including, but not limited to, a second pandemic wave, a difficult labour market due to an economic recession, and limitations in educational opportunities.

Chloroquine against malaria, cancers and viral diseases

Quinoline (QN) derivatives are often used for the prophylaxis and treatment of malaria. Chloroquine (CQ), a protonated, weakly basic drug, exerts its antimalarial effect mainly by increasing pH and accumulating in the food vacuole of the parasites. Repurposing CQ is an emerging strategy for new indications. Given the inhibition of autophagy and its immunomodulatory action, CQ shows positive efficacy against cancer and viral diseases, including Coronavirus 2019 (COVID-19). Here, we review the underlying mechanisms behind the antimalarial, anticancer and antiviral effects of CQ. We also discuss the clinical evidence for the use of CQ and hydroxychloroquine (HCQ) against COVID-19.

Prophylactic (hydroxy)chloroquine in COVID-19: Potential relevance for cardiac arrhythmia risk

(Hydroxy)chloroquine ((H)CQ) is being investigated as a treatment for COVID-19, but studies have so far demonstrated either no or a small benefit. However, these studies have been mostly performed in patients admitted to the hospital and hence likely already (severely) affected. Another suggested approach uses prophylactic (H)CQ treatment aimed at preventing either severe acute respiratory syndrome coronavirus 2 infection or the development of disease. A substantial number of clinical trials are planned or underway aimed at assessing the prophylactic benefit of (H)CQ. However, (H)CQ may lead to QT prolongation and potentially induce life-threatening arrhythmias. This may be of particular relevance to patients with preexisting cardiovascular disease and those taking other QT-prolonging drugs. In addition, it is known that a certain percentage of the population carries genetic variant(s) that reduces their repolarization reserve, predisposing them to (H)CQ-induced QT prolongation, and this may be more relevant to female patients who already have a longer QT interval to start with. This review provides an overview of the current evidence on (H)CQ therapy in patients with COVID-19 and discusses different strategies for prophylactic (H)CQ therapy (ie, preinfection, postexposure, and postinfection). In particular, the potential cardiac effects, including QT prolongation and arrhythmias, will be addressed. Based on these insights, recommendations will be presented as to which preventive measures should be taken when giving (H)CQ prophylactically, including electrocardiographic monitoring.