The cardiac safety of chloroquine phosphate treatment in patients with systemic lupus erythematosus: the influence on arrhythmia, heart rate variability and repolarization parameters.

Antimalarials are used to treat cutaneous and systemic lupus erythematosus (SLE). Even though cardiac damage is a rare complication, over the last decade several reports have raised the issue of cardiotoxicity associated with antimalarials. Therefore, the aim of study was to evaluate the influence of seven-month chloroquine treatment with a 250mg daily dose on arrhythmia, conduction disturbances as well as heart rate variability and repolarization parameters assessed in 24-hour Holter monitoring. The studied group included 28 SLE patients treated with chloroquine as a monotherapy. In all the patients standard 12 leads surface ECG (50 mm) and the 24-hour ECG Holter monitoring (Oxford Medilog Excel-2) were performed before and after chloroquine phosphate treatment. All subjects presented sinus rhythm both at the enrollment and after treatment. No episodes of paroxysmal arrhythmias or conduction disturbances were reported during the study. All the patients were characterized by tendency to tachycardia, but no significant differences in mean heart rate were found before and after chloroquine administration. Similarly, no changes in heart rate variability or repolarization parameters were observed.