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A 63-year-old female with a history of diabetes, prior myocardial infarction, and an ischemic cardiomyopathy with a left ventricular ejection fraction of 35% presents to the emergency department with shortness of breath with minimal exertion, as well as three pillow orthopnea, and paroxysmal nocturnal dyspnea. Six months prior to presentation, she was able to walk 3-blocks which has progressively worsened. One month prior she was started on Digoxin 0.125 mg in addition to her regimen of Metoprolol Succinate 25 mg, Lisinopril 2.5 mg, Spironolactone 25 mg, Aspirin 81 mg, and Plavix 75 mg (all daily), in addition to Metformin 1000 mg twice-a-day. In the emergency department, her initial vital signs show her to be afebrile, with a heart rate of 102 beats-per-minute, and a blood pressure of 90/66 mm Hg. Examination notes an elevated jugular venous pressure with a positive hepatojugular reflex. She has bibasilar crackles, an S3 on cardiac auscultation, and 1+ pitting edema with cool lower extremities. Chest x-ray demonstrates pulmonary edema, and an ECG shows sinus tachycardia with q-waves in leads V1-V3 (known from previous), and unchanged intervals and ST segments. Initial labs are notable for a sodium of 130 mmol/L, a serum creatinine of 1.6 mg/dL, a lactate of 3.1 mmol/L, and a troponin I of 0.93 ng/mL that remains unchanged 4-hours later. The managing team was confronted with a series of questions regarding the differential diagnosis, prognosis, and next management steps.
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Modern-day critical care cardiology is predicated on the ready use of hemodynamically active agents including inotropes and vasopressors. Vasoactive medications are far from advents of the 20th century. Ancient Egyptian texts suggest the use of sea onion as a treatment for edema, which was later noted to be a natural cardiac glycoside. Another cardiac glycoside-containing plant, foxglove, was also commonly used as early as the 1500s. Since then, the active ingredient has been extracted, and in 1785, Sir William Withering published his book on the account of foxglove, extolling its ability to treat edematous states, irregular heartbeats, and heart failure (HF). Its modern form is digitalis.2 In 1893, Dr George Oliver, a British physician, began testing glandular extracts using his son as a research subject. He discovered adrenal extracts caused vasoconstriction. Later efforts on these same extracts led to the first vasopressor, suprarenin, later renamed as epinephrine. As epinephrine quickly became adopted by leading physicians, chemist Helmut Legerlotz synthetized what is now recognized as modern-day phenylephrine (1920s) and, by the 1940s, isoproterenol came to market via researchers in Germany. Isoproterenol quickly became a staple in treating acute cardiac disease. Isoproterenol functioned primarily through changes in chronotropy rather than inotropy. The hope for modified function of isoproterenol led to Ronald Tuttle and Jack Mills removing a side chain hydroxyl group that resulted in an agent with potent inotropic properties, now known as dobutamine (1975).3 Dobutamine continues to be a vital tool in the treatment ...