Question

A 68-year-old man presents to the clinic for evaluation of progressive shortness of breath, fatigue, and right-sided abdominal discomfort that has worsened over the past three weeks. One month ago, he underwent uncomplicated placement of a dual-chamber transvenous pacemaker for symptomatic third-degree atrioventricular block. His medical history includes severe chronic obstructive pulmonary disease, for which he uses a daily inhaled long-acting muscarinic antagonist and an inhaled corticosteroid-long-acting beta-agonist combination.

Vital signs show a temperature of $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure of $115/70\text{ mm Hg}$, and a paced pulse of $72\text{/min}$. Oxygen saturation is $94\%$ on room air.

Physical examination reveals distended neck veins while sitting at a $45^\circ$ angle, with a jugular venous pressure of $15\text{ cm H}_2\text{O}$ and a prominent, rapid positive wave occurring during ventricular systole. Pulmonary auscultation demonstrates a prolonged expiratory phase with scattered bilateral wheezes. Cardiac examination reveals a regular rate and a grade $3/6$ blowing holosystolic murmur at the left lower sternal border that becomes louder during inspiration. The liver is enlarged and exhibits a palpable systolic pulsation. There is $2+$ pitting edema in both lower extremities up to the knees. Laboratory studies show a normal leukocyte count and a serum creatinine of $1.1\text{ mg/dL}$.

Which of the following is the most appropriate next step in the management of this patient?