In a new study, researchers report that a patient who used chloroquine therapy to fight against COVID-19 had a very abnormal ECG pattern after treatment began.
This led to multiple episodes of torsade de pointes (TdP), a life-threatening arrhythmia in which the lower chambers of the heartbeat out of sync with the upper chambers.
Her condition was resolved after chloroquine was discontinued.
The research was conducted by a team at Tel Aviv University and elsewhere.
Chloroquine and hydroxychloroquine are commonly used to treat malaria and some rheumatic diseases. Their use as a treatment for COVID-19 has been widely debated in medical journals and the popular press.
The team presented the first description of the heart problem due to chloroquine treatment in a patient with COVID-19.
They say, on the one hand, these drugs are known to cause prolongation of a specific ECG interval called QT interval.
On the other hand, there is no evidence of sudden, unexplained death when they are used to treat malaria.
And by the same token, neither the American nor the European rheumatology societies recommend electrocardiographic (ECG) surveillance for patients who receive long-term treatment with hydroxychloroquine.
The patient, an 84-year-old women with a history of breast cancer and controlled hypertension was admitted to the hospital with COVID-19.
Her medications included letrozole, prescribed for breast cancer, and memantine, prescribed for Alzheimer’s disease.
An ECG found her corrected QT (QTc) interval was 462 milliseconds, borderline high but still below the 500-millisecond limit suggested by safety guidelines for chloroquine treatment.
Her condition worsened and chloroquine therapy was introduced. After five days of treatment, there was no change to her clinical status, however, a follow-up ECG showed signs of an extremely elongated QTc interval of 627 milliseconds.
Chloroquine was discontinued, as were other drugs known or suspected of causing QT-prolongation, including memantine and letrozole.
The patient was placed on a continuous ECG monitor and given potassium supplements to prevent arrhythmias. Six hours later episodes of TdP were noted on her ECG.
She received treatment that led to an immediate resolution of the ventricular arrhythmias, and her QT interval gradually normalized. She was released after two weeks.
The team notes that chloroquine therapy is not free of risk in patients with COVID-19, particularly in those with high-risk features for QT prolongation and heart rhythm problems.
One author of the study is Yishay Szekely, MD, Department of Cardiology.
The study is published in Heart Rhythm.
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