A 25-year-old woman presents with fever, dehydration, and HR 128/min. ECG shows sinus tachycardia. Which underlying driver is most consistent with sinus tachycardia physiology?

A 58-year-old with severe aortic stenosis develops exertional syncope. Which mechanism most directly contributes to syncope during activity?  

A hospitalized patient on bed rest develops unilateral leg swelling and pain. Which triad best explains the risk factors for this condition?

A patient asks why pulse pressure widens with aging. The best explanation is:  

Which phase of the ventricular action potential is most responsible for excitation–contraction coupling?

A patient with acute leukemia develops dyspnea and confusion with very high WBC count. Which complication is most likely?

A patient with cirrhosis has generalized edema. Which Starling force change is most central?  

A 68-year-old with long-standing hypertension presents with abrupt, severe chest pain radiating to the back described as “tearing.” BP is 210/110. Which pathophysiologic event most likely explains the presentation?  

A patient is diagnosed with lymphoma. Which finding most strongly supports Hodgkin lymphoma rather than non-Hodgkin lymphoma?  

A patient stands up quickly and becomes lightheaded. Which immediate reflex response should occur in a healthy person?