Beyond the Irregular Beat: An Unexpected Case of Raynaud's Phenomenon in a Patient with Atrial Fibrillation.

Raynaud's phenomenon is characterized by episodic vasospasm of the extremities, often triggered by cold or stress. It is a hallmark of systemic sclerosis (SSc) and is frequently associated with pulmonary arterial hypertension (PAH). PAH may cause right atrial dilatation, predisposing to atrial fibrillation (AF). While Raynaud's and PAH are well-documented, their coexistence with AF is rarely reported. A 71-year-old male presented with rapid AF and pulmonary oedema. On admission, vital signs were stable, but he developed symmetrical discoloration of the fingers, palms, and feet after cold exposure in the ICU, accompanied by numbness and pain. Laboratory tests revealed prolonged PT, high ESR (65/121 mm/hr), and positive ANA (44.8 IU/mL). ECG showed rapid AF with left ventricular hypertrophy. Chest X-ray demonstrated pulmonary artery dilatation and cardiomegaly. Echocardiography revealed moderate tricuspid regurgitation and severe PAH. This case illustrates a rare combination of Raynaud's phenomenon, PAH, and AF, likely secondary to autoimmune vascular dysfunction. PAH-induced atrial dilatation may trigger AF, while endothelial dysfunction may worsen Raynaud's symptoms. A positive ANA suggests underlying SSc or SLE. Early recognition and multidisciplinary management targeting pulmonary pressure, arrhythmia control, and vasospasm are crucial to prevent complications. Long-term outcome was not assessed due to loss to follow-up.