Cardiac Diseases in Pregnancy Flashcards
Hemodynamic & Cardiovascular changes begin _____ in pregnancy, _______ during the late _____ trimester & remain ________ until delivery.
early, peak, 2nd, constant
1st Trimester
0 - 13 weeks
2nd Trimester
14 - 26 weeks
3rd Trimester
27 - 40 weeks
Hemodynamic & Cardiovascular changes affect?
- Cardiac output
- Blood pressure
- Systemic vascular resistance
- Heart rate
- Blood volume
Define Systemic Vascular Resistance
The resistance that must be overcome to push blood through the systemic circulation & create flow.
Change in systemic vascular resistance in pregnancy
(either increases or decreases)
- Drops by approx. 35 - 40% from around 5 wks gestation and nadirs (low point) in the mid-2nd trimester.
Drop in systemic vascular resistance is due to?
Systemic vasodilation due to pregnancy
Define Cardiac Output (CO)
The volume of blood that is pumped by the heart every minute.
CO = stroke volume (SV) x heart rate (HR)
Cardiac output equation
CO = stroke volume (SV) x heart rate (HR)
Change in cardiac output (CO) in pregnancy
(either increases or decreases)
It begins to rise in the 2nd trimester & peaks during the 3rd trimester.
Change in heart rate (HR) in pregnancy
(either increases or decreases)
HR rises throughout gestation & peaks in late 3rd trimester at average of 16bpm above non-pregnant valves.
Change in blood pressure (BP) in pregnancy
(either increases or decreases)
Falls gradually around 12 wks gestation & reaches nadir (low point) at 18 wks gestation
THEN
gradually rises to pre-pregnant levels at term (>37 wks)
Normal pregnancy is characterized by:
- an increase in cardiac output CO
- reduction in systemic vascular resistance
- minimal change in mean blood pressure
Change in blood volume in pregnancy
(either increases or decreases)
Increases due to increase in plasma volume & red blood cell mass.