Heart failure pathophysiology — MCQs

A 40-year-old female volunteers for an invasive study to measure her cardiac function. She has no previous cardiovascular history and takes no medications. With the test subject at rest, the following data is collected using blood tests, intravascular probes, and a closed rebreathing circuit: Blood hemoglobin concentration 14 g/dL Arterial oxygen content 0.22 mL O2/mL Arterial oxygen saturation 98% Venous oxygen content 0.17 mL O2/mL Venous oxygen saturation 78% Oxygen consumption 250 mL/min The patient's pulse is 75/min, respiratory rate is 14/ min, and blood pressure is 125/70 mm Hg. What is the cardiac output of this volunteer?

An investigator is studying patients with acute decompensated congestive heart failure. He takes measurements of a hormone released from atrial myocytes, as well as serial measurements of left atrial and left ventricular pressures. The investigator observes a positive correlation between left atrial pressures and the serum level of this hormone. Which of the following is most likely the mechanism of action of this hormone?

A 59-year-old man with a history of congestive heart failure presents to his cardiologist for a follow-up visit. His past medical history is notable for diabetes mellitus, hypertension, and obesity. He takes metformin, glyburide, aspirin, lisinopril, and metoprolol. He has a 40 pack-year smoking history and drinks alcohol socially. His temperature is 99.1°F (37.2°C), blood pressure is 150/65 mmHg, pulse is 75/min, and respirations are 20/min. Physical examination reveals bilateral rales at the lung bases and 1+ edema in the bilateral legs. The physician decides to start the patient on an additional diuretic but warns the patient about an increased risk of breast enlargement. Which of the following is the most immediate physiologic effect of the medication in question?

A 65-year-old male with a history of CHF presents to the emergency room with shortness of breath, lower leg edema, and fatigue. He is diagnosed with acute decompensated congestive heart failure, was admitted to the CCU, and treated with a medication that targets beta-1 adrenergic receptors preferentially over beta-2 adrenergic receptors. The prescribing physician explained that this medication would only be used temporarily as its efficacy decreases within 2-3 days due to receptor downregulation. Which of the following was prescribed?

A 55-year-old man presents to the emergency department with shortness of breath and weakness. Past medical history includes coronary artery disease, arterial hypertension, and chronic heart failure. He reports that the symptoms started around 2 weeks ago and have been gradually worsening. His temperature is 36.5°C (97.7°F), blood pressure is 135/90 mm Hg, heart rate is 95/min, respiratory rate is 24/min, and oxygen saturation is 94% on room air. On examination, mild jugular venous distention is noted. Auscultation reveals bilateral loud crackles. Pitting edema of the lower extremities is noted symmetrically. His plasma brain natriuretic peptide level on rapid bedside assay is 500 pg/mL (reference range < 125 pg/mL). A chest X-ray shows enlarged cardiac silhouette. He is diagnosed with acute on chronic left heart failure with pulmonary edema and receives immediate care with furosemide. The physician proposes a drug trial with a new BNP stabilizing agent. Which of the following changes below are expected to happen if the patient is enrolled in this trial?

A 71-year-old man presents to his cardiologist with a 1-month history of increasing shortness of breath. He says that he is finding it very difficult to walk up the flight of stairs to his bedroom and he is no longer able to sleep flat on his bed because he wakes up choking for breath. His past medical history is significant for a myocardial infarction 3 years ago. On physical exam, he is found to have diffuse, moist crackles bilaterally on pulmonary auscultation and pitting edema in his lower extremities. Serum tests reveal an increased abundance of a product produced by cardiac myocytes. Which of the following most likely describes the function of this product?

A 72-year-old man with type 2 diabetes mellitus, hypertension, and systolic heart failure comes to the physician because of a 5-day history of progressively worsening shortness of breath at rest. Physical examination shows jugular venous distention, diffuse crackles over the lower lung fields, and bilateral lower extremity edema. As a part of treatment, he is given a derivative of a hormone that acts by altering guanylate cyclase activity. This drug has been found to reduce pulmonary capillary wedge pressure and causes systemic hypotension as an adverse effect. The drug is most likely a derivative of which of the following hormones?

A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

You are interested in studying the etiology of heart failure reduced ejection fraction (HFrEF) and attempt to construct an appropriate design study. Specifically, you wish to look for potential causality between dietary glucose consumption and HFrEF. Which of the following study designs would allow you to assess for and determine this causality?

A 42-year-old woman comes to the physician because of 2 episodes of loss of consciousness over the past week. She recovered immediately and was not confused following the episodes. During the past 5 months, she has also had increased shortness of breath and palpitations. She has been unable to carry out her daily activities. She also reports some chest tightness that resolves with rest. She has no history of serious illness and takes no medications. She immigrated with her family from India 10 years ago. Her temperature is 37.3°C (99.1°F), pulse is 115/min and irregular, and blood pressure is 108/70 mm Hg. Examination shows jugular venous distention and pitting edema below the knees. Bilateral crackles are heard at the lung bases. Cardiac examination shows an accentuated and split S2. There is an opening snap followed by a low-pitched diastolic murmur in the fifth left intercostal space at the midclavicular line. An ECG shows atrial fibrillation and right axis deviation. Which of the following is the most likely underlying mechanism of these findings?