Samantha, a 74-year-old woman with a history of rheumatic feverwhile in her twenties, presented to her physician with complaintsof increasing shortness of breath (\"dyspnea\") upon exertion. Shealso noted that the typical swelling she's had in her ankles foryears has started to get worse over the past two months, making itespecially difficult to get her shoes on toward the end of the day.In the past week, she's had a decreased appetite, some nausea andvomiting, and tenderness in the right upper quadrant of theabdomen.On physical examination, Samantha's jugular veins werenoticeably distended. Auscultation of the heart revealed alow-pitched, rumbling systolic murmur, heard best over the leftupper sternal border. In addition, she had an extra, \"S3\" heartsound. A chest X-ray reveals a normal cardiac silhouette that isnormal in diameter, but her physical examination revealshepatomegaly and ascites, as well as pitting edema in her ankles.She is advised to wear support stockings and given a prescriptionfor digoxin. Two weeks later she returns to the office for afollow-up visit; upon physical examination, she still hassignificant hepatomegaly and pitting edema, and is significantlyhypertensive (i.e. she has high blood pressure). Her physicianprescribes a diuretic called furosemide (or \"Lasix\").
1. What is causing the low-pitched, rumbling murmur (both ingeneral and specific anatomical and physiological terms)? Why is itheard best over the left upper sternal border? Which valve isinvolved?
2. What is causing the \"S3\" heart sound? What portion of thecardiac cycle will it be heard in and why?
3. Is Samantha's history of rheumatic fever relevant to thecurrent symptoms? Why or why not? What causes rheumatic fever andwhat might it cause in Samantha years after her infection? Why isthe diagnosis of the specific valve involved in the systolic murmurimportant?
4. Does the normal diameter of the heart on X-ray rule out apossible cardiac diagnosis? What is meant by the term “concentrichypertrophy†and why might it be happening in Samantha’s heart?
5. What is meant by the terms “hepatomegaly†and “ascites†andwhy are they happening? Why are her jugular veins distended? Bespecific in terms of blood pressure and Starling forces.
6. What is pitting edema and what is causing it?
7. Why is she advised to wear support stockings? If she hadatherosclerosis or blockage of a femoral artery, would this be anadvisable diagnosis? Why or why not?
8. Is the stress being placed on Samantha’s heart pre-load orafter-load and why?
9. What is the general diagnosis for Samantha’s condition? Whatwould the diagnosis be if there were pulmonary edema instead ofsystemic edema?
10. Why is Samantha started on digoxin? How does it work? Stateyour answers in terms of chronotropism and inotropism, the Na+/K+ATPase, cytoplasmic Ca++ concentrations, and the proteins in acardiomyocyte’s sarcomere.
11. What happened to Samantha in the two weeks before herfollow-up visit? In other words, how did her body begin tocompensate for decreased stroke volume? Utilize cardiac output,sympathetic nervous system, vasoconstriction to “less vital†organs(including the kidney) the renin-angiotensin-aldosterone (R-A-A)axis, Angiotensin II, ADH, pre-load and after-load, theFrank-Starling law, and the actions of digoxin.
12. Why was she given Lasix medication, and how does itwork?
