Spontaneous Hemorrhagic Pericardial Effusion as a Consequence of Apixaban Utilization for New-Onset Atrial Fibrillation.

Although anticoagulation stands as a standardized therapeutic approach for mitigating thrombotic risks in atrial fibrillation, the potential for bleeding associated with direct oral anticoagulants (DOACs) is consistently weighed in the risk/benefit analysis prior to initiating therapy for non-valvular atrial fibrillation. While the typical bleeding risks from DOACs predominantly affect the gastrointestinal system, occurrences of spontaneous hemorrhagic pericardial effusions are rare. This case presentation illustrates a patient developing spontaneous hemorrhagic pericardial effusion four days after commencing apixaban therapy and subsequent management.