A 71-year-old woman visits the emergency room after experiencing orthopnea and increasing dyspnea for the past week. She has a 15% left ventricular ejection fraction, a history of myocardial infarction, and systolic heart failure. Medications taken by the patient, including carvedilol, furosemide, aspirin, lisinopril, and atorvastatin, are taken as prescribed. Both the blood pressure and the pulse measure 118/74 mm Hg. Bilateral lower extremities pitting edema, bibasilar crackles, an S3 heart sound, and high jugular venous pressure are all found during the examination. Dobutamine infusion is started for the patient, which significantly reduces their symptoms. A little improvement in cardiac contractility is seen on an echocardiogram. Which of the following is the likely mechanism underlying this patient's clinical improvement?

Question

A 71-year-old woman visits the emergency room after experiencing orthopnea and increasing dyspnea for the past week. She has a 15% left ventricular ejection fraction, a history of myocardial infarction, and systolic heart failure. Medications taken by the patient, including carvedilol, furosemide, aspirin, lisinopril, and atorvastatin, are taken as prescribed. Both the blood pressure and the pulse measure 118/74 mm Hg. Bilateral lower extremities pitting edema, bibasilar crackles, an S3 heart sound, and high jugular venous pressure are all found during the examination. Dobutamine infusion is started for the patient, which significantly reduces their symptoms. A little improvement in cardiac contractility is seen on an echocardiogram. Which of the following is the likely mechanism underlying this patient's clinical improvement?

Quizplus · Accepted Answer

Eductional Objective: Dobutamine is a beta -adrenergic agonist that primarily activates 1 receptors while having marginal effects on 2 and 1 receptors. Increased cAMP synthesis and cytosolic Ca²⁺+ levels result from stimulation of 1 receptors. This makes actin and myosin interact more easily, increasing the contractility of the myocardium.

A 71-Year-Old Woman Visits the Emergency Room After Experiencing Orthopnea