EKG heart rhythm

The antimalarial drug hydroxychloroquine does not appear to affect heart rhythm in lupus patients, even if they have chronic kidney disease.

That’s according to new research presented at ACR Convergence 2020, the annual meeting of the American College of Rheumatology, in which researchers studied data of 194 lupus patients from an electronic medical records database at NYU Langone Health from March 2012 to May 2020.

Systemic lupus erythematosus (SLE or lupus) is an autoimmune disease that causes systemic inflammation that can affect multiple organs, including the skin, joins, kidneys, tissue lining the lungs, heart, and brain.

Chronic kidney disease is a complication of lupus that can be associated with higher levels of hydroxychloroquine, which is a commonly prescribed medication for lupus.

Hydroxychloroquine is considered a “first-line” therapy for lupus, which means it is prescribed to most newly diagnosed patients. It is typically well-tolerated and considered low-risk for side effects.

While hydroxychloroquine can cause a delay in the heart’s electrical conduction system, previous research in people with lupus shows there is not a serious risk of abnormal heart rhythm.

That said, there has been a concern that lupus patients with reduced kidney function may be more likely to experience heart side effects from higher levels of hydroxychloroquine.

The QTc interval measurement on an electrocardiogram (EKG) is a way to assess the heart’s electrical signaling. It measures the time it takes the heart to contract and relax with each heartbeat. People who have longer QT intervals have a higher risk for heart arrhythmias, or irregular heartbeats, which would be life-threatening.

“Hydroxychloroquine use increased during the COVID-19 pandemic, with some contradictory reports regarding its cardiac safety,” the study’s coauthor, H. Michael Belmont, MD, Professor of Medicine at New York University Grossman School of Medicine and codirector of NYU Lupus Center, said in a press release. “It is important to provide reassurance to lupus patients who need to take this medication regularly and for long periods that it is generally safe and without consequential risk for serious heart toxicity.”

In the study, researchers collected data on the 194 patients’ EKG results, including the QTc intervals from their first and final EKGs.

Prolonged QTc intervals are considered more than 450 milliseconds for men and more than 470 milliseconds for women, while severe prolongation is more than 500 milliseconds. Researchers also tracked patients’ levels of creatinine (a waste product that increases in your body when your kidneys aren’t functioning properly), demographics, and whether or not they had CKD.

The researchers found there was no significant difference in QTc intervals based on whether or not people were taking hydroxychloroquine.

When researchers looked specifically at lupus patients with chronic kidney disease, they found that this group was more likely to have prolonged QTc when compared to those without chronic kidney disease, but they did not have any significant differences in their mean QTc intervals based on their hydroxychloroquine use.

What’s more, none of these patients had documented tachyarrhythmia (a more rapid than normal heart rate) or Torsades de pointes (Tdp), a life-threatening arrhythmia.

“The findings of this study can provide some comfort to lupus patients, including those with chronic kidney disease, that hydroxychloroquine is not likely to produce serious heart arrhythmias,” said Dr. Belmont. “Future studies could investigate these observations in even larger numbers of patients and include a prospective examination of QTc intervals in patients before and after starting the medication to provide even further assurance of drug safety.”

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Haj-Ali M, et al. Hydroxychloroquine and QTc Prolongation in a Cohort of SLE Patients [abstract]. Arthritis & Rheumatology. November 2020. https://acrabstracts.org/abstract/hydroxychloroquine-and-qtc-prolongation-in-a-cohort-of-sle-patients.

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