A 49-year-old man with a long-standing history of chronic renal failure as a consequence of diabetic nephropathy is brought to the emergency room for nausea, lethargy, and confusion. His physical examination is significant for an elevated jugular venous pressure, clear lung fields, and harsh systolic and diastolic sounds heard over the precordium.
Serum chemistries reveal K 5.1 mEq/L, CO2 17 mEq/L, BUN 145 mg/dL, and creatinine 9.8 mg/dL.