Background/Purpose: Methylprednisolone (MP) in both high dose (2mg/kg or higher) and pulse dose (30mg/kg up to 1000mg) is often used to treat patients with connective tissue diseases, as these doses are more effective in controlling exacerbations than lower doses. We present 6 patients with SLE who experienced bradycardia after pulse-dose MP. Three of these patients had EKGs which revealed sinus bradycardia, with heart rates decreasing below 60 beats per minute, and occasionally as much as 40%-50% below baseline. There is scarce literature explaining this occurrence, so those who are unfamiliar with steroid induced bradycardia might order redundant lab tests and imaging to further evaluate this phenomenon.

Methods: Review of patient medical records and the literature on this topic.

Results: The mechanism for this dysrhythmia remains unclear. It could be multifactorial, however one theory is that steroids, through their effect on the potassium and sodium balance in the body, may cause acute electrolyte shifts across the myocardial cell membranes, and another theory suggests that a subsequent increase in intravascular volume may trigger a reflex bradycardia. In adults, there are reports of steroid-induced bradycardia in patients with a number of different autoimmune conditions. In children, there is little literature on this topic. Herein, we report 6 children with SLE who experienced bradycardia subsequent to high dose or pulse MP infusions. However, contrary to what has been found before, in our review of the patients, the bradycardia occurred within 4 to 24 hours of receiving MP and resolved within 24hours of discontinuation. During this time, the patients were not symptomatic, and EKG revealed sinus bradycardia.