A 54 year-old male presents to the emergency department with symptoms of intermittent palpitations and mild dyspnea over the past few days. He denies chest pain, pressure or tightness. His past medical history is significant for type 2 diabetes which is diet controlled and hypertension which is well-controlled with Hydrochlorothiazide. In addition to his Hctz, he takes a daily aspirin. He is a non-smoker, but admits to daily alcohol use for years. His physical exam reveals an irregular heart beat at 112 bpm and bi-basilar rales on auscultation. His BP is 158/88 and the oxygen saturation is 95% on room air. His ECG, unsurprisingly reveals atrial fibrillation with a ventricular rate of 115 bpm and without other signs of acute ischemia.
A chest x-ray is performed:
1. What finding is indicated by the arrow on this chest radiograph?
2. What is this etiology of this finding?