Soru

A 71-year-old man with a 40-pack-year smoking history and diet-controlled type 2 diabetes mellitus arrives at the emergency department with a 3-day history of progressively worsening shortness of breath. He reports a dry cough that frequently awakens him from sleep. His temperature is $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), blood pressure is $165/95\text{ mmHg}$, pulse is $110/\text{min}$, and respiratory rate is $28/\text{min}$. Pulse oximetry shows $89\%$ on room air. Physical examination reveals diffuse expiratory wheezing, a prolonged expiratory phase, and an elevated jugular venous pressure. The physician suspects that an acute cardiovascular condition may be mimicking a primary pulmonary process. Which of the following additional findings would be most specific for confirming an acute cardiogenic etiology for this patient's respiratory distress rather than an exacerbation of chronic obstructive pulmonary disease?