Review Question - QID 214532

A 56-year-old man presents to the emergency department with exertional dyspnea, poor sleep, and bilateral lower extremity swelling. Two weeks prior to presentation he had an upper respiratory viral infection that he symptomatically managed. He has a medical history of hypertension, hyperlipidemia, type 2 diabetes mellitus, heart failure with reduced ejection fraction, and coronary artery disease requiring drug-eluting stent placement. Physical examination is remarkable for jugular venous distension, pulmonary crackles, and bilateral pitting edema up to the knees. He is admitted to the cardiac step-down unit and is appropriately treated. Approximately 3 days later the patient develops palpitations and lightheadedness. His telemetry is shown in Figure A. Which of the following is most likely the cause of this patient's symptoms?