An 83-yeаr-оld mаle with а histоry оf HTN, HL, obesity, and atrial fibrillation presents to the ED with complaints of dyspnea on exertion, orthopnea, and bilateral lower extremity edema. A N-terminal pro-BNP (NTpro-BNP) is drawn and comes back at 24,636 pg/mL. Which of the following is the next BEST diagnostic study based on this patient’s clinical presentation and laboratory results?