Cumulative dose of hydroxychloroquine is associated with a decrease of resting heart rate in patients with systemic...

Area of Science:

• Cardiology
• Rheumatology
• Pharmacology

Background:

• Hydroxychloroquine (HCQ) is widely used for systemic lupus erythematosus (SLE) management.
• While beneficial, HCQ carries risks of cardiotoxicity, including heart conduction disturbances and heart failure.

Purpose of the Study:

• To investigate the impact of HCQ on resting heart rate (RHR) in SLE patients.
• To determine if cumulative HCQ dose influences RHR in this population.

Main Methods:

• A study included 42 non-active SLE patients with sedentary lifestyles on HCQ.
• Exclusion criteria included beta-blocker use, training, pacemakers, anemia, renal disease, COPD, obesity, thyroid disease, fever, or infection.
• Standard 12-lead ECGs were performed, and data analyzed using Mann-Whitney U test and multiple linear regression.

Main Results:

• Patients were grouped by cumulative HCQ dose (CD-HCQ): low (<365g, n=24) and high (>365g, n=18).
• The high-HCQ group showed a significant 11% decrease in mean RHR (65±7 bpm) compared to the low-HCQ group (73±6 bpm) (p=0.003).
• RHR decrease was significantly associated with CD-HCQ (p=0.024) and duration of HCQ exposure (p=0.029).

Conclusions:

• Cumulative HCQ doses exceeding 365g are linked to a significant reduction in RHR among non-active SLE patients.
• This finding suggests a potential dose-dependent effect of HCQ on heart rate.
• Further prospective studies are needed for more conclusive evidence.