Impact of Hydroxychloroquine Treatment of COVID-19 on Cardiac Conduction: The Beat Goes On

Abstract

Objectives: Our study aimed to investigate the frequency of malignant cardiac arrhythmias in hospitalized patients receiving hydroxychloroquine alone and those receiving a combination of hydroxychloroquine with azithromycin, as well as the quantitative extent of QT prolongation within Tisdale Risk Score (TRS) categories. Background: There have been over 33 million cases of SARS-CoV-2 (COVID-19) resulting in over 600,000 deaths in the United States. As the current COVID-19 pandemic continues, numerous medications have been administered to attempt to treat patients afflicted by the disease. While hydroxychloroquine has been in use for decades for rheumatologic and infectious disease processes, it does have potential cardiotoxicity related to drug-induced QT prolongation. Drug-induced QT prolongation has an increased risk of arrhythmogenicity, potentially progressing into torsades de pointes (TdP) and increased patient mortality. The relationship between QT prolongation and TdP is complex and inexact, but there remains optimism regarding the use of these medications in the treatment of COVID-19 despite limited data on their true efficacy. Methods: We retrospectively identified 75 patients who were admitted with COVID-19 and underwent treatment with hydroxychloroquine for 5 days. The hydroxychloroquine protocol was defined as an initial dose of 400 mg BID for the first day, followed by 400 mg daily for the next 4 days. Baseline demographics, medications, medical histories, lab values, ECG QT intervals, and Tisdale Risk Categories were collected for all patients. Results: Seventy-four (98.7%) patients completed the full course of hydroxychloroquine. There were 41 males (54.7%) and 34 females (45.3%). Average length of stay was 8.9 days (95% CI: 7.5, 10.2). One patient who could not complete the course due to inability to swallow medication tablets. There were no reports of new arrythmias or incidence of torsades de pointes during the study. Seventy-two patients (96%) were taking at least 2 QT prolonging medications. The average corrected QT intervals were as follows: day 1 of admission was 421.62 milliseconds (n = 66, 95% CI: 412.19, 431.05), day 2 was 431.50 ms (n = 30, 95% CI: 416.34, 446.66), day 3 was 433.48 ms (n = 23, 95% CI: 413.34, 453.61), day 4 was 427.59 ms (n = 17, 95% CI: 400.83, 454.35), and day 5 was 444.28 ms (n = 18, 95% CI: 428.43, 460.12). The corrected QT interval prolonged by 22.66 ms from day 1 to day 5 (p = 0.03) in the overall population. Conclusion: There were no patients who experienced arrhythmogenicity or Torsades de Pointes despite a statistically significant increase in QTc intervals after patients received the 5-day course of hydroxychloroquine for treatment of COVID-19.