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Physiology

Cardiac Cycle and Hemodynamics Practice Questions

21 free Cardiac Cycle and Hemodynamics practice questions for the USMLE Step 1, each with the correct answer and a detailed explanation. Open any question below, or take the full set as an interactive quiz.

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All Cardiac Cycle and Hemodynamics questions

21 questions
  1. Q1. Which of the following best describes the first sound (S1) heard during the cardiac cycle?
  2. Q2. During which phase of the cardiac cycle does isovolumetric contraction occur?
  3. Q3. How is stroke volume (SV) defined in terms of ventricular volumes?
  4. Q4. Which factor does NOT increase stroke volume under physiologic conditions?
  5. Q5. What does preload most directly reflect in the context of cardiac function?
  6. Q6. Which of the following defines afterload for the left ventricle in most physiologic descriptions?
  7. Q7. Which equation correctly defines cardiac output (CO)?
  8. Q8. According to the Frank–Starling mechanism, what happens when venous return to the heart increases acutely (within the physiologic range)?
  9. Q9. Which phase of the cardiac cycle corresponds to the rapid ejection phase when aortic valve opens and blood is expelled into the aorta?
  10. Q10. What effect does an acute increase in systemic vascular resistance (i.e., increased afterload) have on stroke volume if other factors remain constant?
  11. Q11. During which part of the cardiac cycle does isovolumetric relaxation occur?
  12. Q12. Which of the following best reflects the relationship between end-diastolic volume (EDV) and myocardial fiber stretch regarding preload?
  13. Q13. What is the primary determinant of the afterload faced by the left ventricle under physiologic conditions?
  14. Q14. Which of the following statements about cardiac output (CO) is correct under steady-state physiology?
  15. Q15. If sympathetic stimulation increases heart contractility (inotropy) without changing preload or afterload, what happens to stroke volume and ejection fraction…
  16. Q16. Which event in the cardiac cycle corresponds most closely with the peak of the QRS complex on ECG in the context of mechanical events?
  17. Q17. Which change would you expect in the left ventricular pressure–volume loop if afterload is acutely increased (e.g., acute hypertension)?
  18. Q18. Which of the following reflexes increases heart rate in response to increased venous return/stretch of the right atrium?
  19. Q19. Which phase of the cardiac cycle contributes most to ventricular filling at rest under normal physiology?
  20. Q20. Which of the following best explains why an increased heart rate alone may not substantially increase cardiac output under certain conditions?
  21. Q21. What happens to ejection fraction (EF) if end-systolic volume (ESV) increases but end-diastolic volume (EDV) remains constant?