Q. A 50-year-old male was admitted through the emergency department 48 hours ago following a symptomatic episode of severe hypertension. He was stabilized and admitted for observation and further diagnostic testing. The patient has a past medical history of hypertension, for which he takes lisinopril and hydrochlorothiazide. He also has a history of hypothyroidism, for which he takes levothyroxine. A concern for congestive heart failure was noted on admission secondary to moderate bilateral lower extremity edema. Subsequently, cardiac ultrasound determined the patient’s ejection fraction was 40 percent, and he was started on 40 mg of IV furosemide twice daily to facilitate diuresis. This morning, staff report the patient has complained overnight of weakness, leg cramps, and fatigue. They report he had difficulty ambulating to the bathroom. On physical examination, the patient appears fatigued and weak. He denies any chest pain, shortness of breath, or palpitations. His vital signs are within normal limits. Heart sounds are regular with no murmurs. Lung sounds are clear. There is no peripheral edema and his abdomen is soft and nontender. There is mild weakness in his proximal muscle groups, and his deep tendon reflexes are reduced. You review his EKG (see image) and bloodwork from today. Laboratory Results: Potassium: 2.3 mEq/L Sodium: 137 mEq/L Chloride: 103 mEq/L Bicarbonate: 24 mEq/L Blood urea nitrogen: 15 mEq/L Creatinine: 1.0 mEq/L Based on the patient's history and diagnostic studies, what is the most likely diagnosis?