Cardiac involvement is present in more than half of the patients with Systemic Lupus Erythematosus (SLE). However, studies on the prevalence of arrhythmias in this disease and laboratory correlations predictive of their development do not exist. It seems possible that the classic second mortality peak is related to arrhythmias, mainly due to the sudden nature of those deaths. Autoimmune process, atherosclerotic complications, and even adverse effects secondary to the treatment of this disorder (chloroquine cardiotoxicity) seem to be the main pathophysiological mechanisms of those disturbances. The direct participation of autoantibodies, such as anti-Ro/SSA and anti-RNP, is still controversial. All types of AV blocks (AVB), intraventricular conduction disturbances, and sick sinus syndrome have already been described in this disease. Tachycardias identified more often include sinus tachycardia, atrial fibrillation, and atrial ectopies. Long QT syndrome and the presence of late potentials in signal-averaged ECG have also been described in SLE patients and they can be associated with increased mortality rates. Cardiac toxicity secondary to chloroquine could be responsible for several types of arrhythmias. However, few cases of fascicular block evolving to complete AV block have been described. Since these adverse effects are rarely reported, the beneficial anti-inflammatory and immune properties support the use of antimalarials in this disease. A complete cardiologic evaluation should include the conduction system and must be carried out in all SLE patients to identify arrhythmias, therefore preventing symptoms and also sudden cardiac death.