Maternal Physio - Cardiovascular Flashcards Preview

OBGYN - 3. OB normal > Maternal Physio - Cardiovascular > Flashcards

Flashcards in Maternal Physio - Cardiovascular Deck (13):
1

Cardiac output changes

  • AOG
  • Why

  • CO ↑ at 5th week AOG due to:
    • ↓ systemic vascular resistance plus ↑ heart rate

2

Plasma volume changes

  • AOG
  • Change
  • Effect

  • Between 10-20 weeks AOG
    • Plasma volume expands
    • ↑ preload

3

Heart position

  • Changes
  • CXR finding

  • Changes
    • Displaced to the left and upward
    • Rotated somewhat on its long axis
  • CXR finding
    • Apex is somewhat lateral from its usual position
    • Larger cardiac silhoutte on chest radiograph
      • some degree of benign pericardial effusion, may increase the cardiac silhoutte

4

ECG change

No characteristic ECG changes other than slight left-axis deviation as a result of the altered heart position

5

Cardiac sounds

  • Exaggerated splitting of the 1st heart sound with increased loudness of both components
  • Systolic murmur in 90% of pregnant patients due to ↑ flow across aortic and pulmonic valves
    • intensified during inspiration
    • disappears shortly after delivery
  • Diastolic murmurs are never normal and should be evaluated by a cardiologist

6

BP changes

  • Arterial pressure usually decreases to a nadir at 24 to 26 weeks

7

How many percent of women experience supine hypotensive syndrome?

About 10%

8

RAA component changes and why

  • Increased on normal pregnancy
    • Renin
      • produced by kidney and placenta
    • Angiotensinogen
      • produced by maternal and fetal liver and influenced by estrogen

 

Memory aid:

  • Vowels; so it is not progesterone

9

If angiotensin is increased, why is there no BP elevation in normal pregnancy?

Because of prostacyclin, which is implicated in the angiotensin resistance characteristic of normal pregnancy

 

Therefore:

  • Prostacyclin is decreased in preeclampsia

10

Diastolic decreases ____ [less/more] than systolic

More

11

Prostaglandin E2 synthesis

  • Where synthesized
  • Increased/decreased release

  • Where synthesized
    • Renal medulla
  • Increased/decreased release
    • Increased markedly in late pregnancy

12

Principal prostaglandin of endothelium

Prostacyclin

13

Potent vasoconstrictor in endothelial and vascular smooth muscle cells which also stimulates secretion of ANP, aldosterone and catecholamines

Endothelin