Anterior Mediastinal Mass Causing Intermittent Atrial Fibrillation

Area of Science:

• Cardiology
• Thoracic Surgery
• Oncology

Background:

• Mediastinal masses are uncommon emergency department presentations, often causing vague symptoms like chest discomfort or dyspnea.
• Cardiac dysrhythmias secondary to mediastinal tumors are rare, usually linked to hormonal or metabolic influences.

Observation:

• A patient presented with atrial fibrillation and rapid ventricular response, alongside a history of recurrent palpitations managed with vagal maneuvers.
• Imaging revealed an anterior mediastinal mass, subsequently diagnosed as a thymoma.

Findings:

• The anterior mediastinal thymoma was suspected as the cause of the patient's atrial fibrillation with rapid ventricular response.
• The dysrhythmia was attributed to the direct mass effect of the thymoma, rather than endocrine or metabolic factors.

Implications:

• This case underscores the importance of considering direct mechanical effects of mediastinal masses on cardiac function.
• Highlights a rare but critical differential diagnosis for unexplained dysrhythmias in the emergency setting.
• Suggests thorough investigation for mediastinal pathology in patients with new-onset or recurrent arrhythmias.