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Flashcards in Cardiology NMS Deck (22):
1

What is CHF

the inability of th heart, working at normal or elevated filling pressure, to pump enough blood to meet the oxygen requirements of the body tissues.

Its a syndrome of disorders, not a diagnosis

2

Systole is governed by what 3 cardiac properties

Contractility
Afterload
preload

3

What is preload

the sarcomere stretch before contraction

4

What property of dysfunction is associated with most cases of CHF

decreased contractility

5

What are the causes of decreased contractility

1. MI: portion of the mycardium undergoes necrosis and can no longer generate force
2. Valvular heart disease: stenosis or regurgitation
3. Hypertension
4. Cariomyopathies

6

How can afterload be quantified

Stress = (pressure x radius) / (2 x thickness)

7

What is the frank-starling mechanism

Increased end diastolic volume increases sarcomere stretch (preload), which increases the number of systolic actin-myosin cross-bridges that develop. Greater number of cross-bridges, the greater the force of contraction.

8

What governs diastolic function

active and passive properties

9

What is the active property of diastolic function

Active relaxation occurs early in diastole as calium is pumped out of the myocardium, resulting in the near cessation of actin myosin cross bridge interaction

10

What is the passive property of diastole

passive filling occurs as the mitral valve opens, allowing the blood stored in the atria to fill the ventricles

11

What is the formula for stiffness

(delta P) / (delta V)

12

What causes an increased in stiffness

Hypertension
Amyloid

13

What are the types of heart failure

1. HIgh output HF
2. Left sided failure
3. Right sided failure

14

What are some causes of high output HF

1. Chronic severe anemia
2. AV fistula
3. beriberi

15

Discuss how chronic anemia leads to high output HF

Chronic severe anemia has a reduced oxygen carrying capacity
- Compensation is provided by increased forward cardiac output, which is facilitated by cardiac enlargement, decreased total PVR and increased venous return: leads to Volume overload
- Eventually the demands on the heart lead to cardiac failure; cardiac output, although high, still is not adequate to meet the circulatory demands placed on the heart by the anemia.

16

What three things will lead to volume overload

1. .Cardiac enlargement
2. Decreased PVR
3. Increased venous return

17

What is the most common cause of Right sided failure

left sided failure.

COPD, PE, pulmonary HTN are also common in the absence of a left sided failure

18

What are the symptoms of CHF

1. Dyspnea (most common)
2. Orthopnea
3. Paroxysmal nocturnal dyspnea
4. Nocturia
5. Edema

19

How does CHF cause nocturia

develops in CHF as a result of increased renal blood flow when the patient is recumbent and asleep.
a. During the day when the skeletal muscles are active, limited cardiac output is shifted away from the kidney toward the skeletal musculature. The kidney interprets this reduction in blood flow as hypovolemia and becomes sodium avid via activation of the renin angiotensin system.
b. During night, when the patient is at rest, cardiac output is shifted toward the kidney, and diuresis ensues.

20

When is peripheral edema is cardiac related, is it caused by right or left failure

RIGHT SIDE

21

What causes edema associated with cardiac

systemic hydrostatic venous pressure is greater than the systemic oncotic pressure.

22

What are the physical signs of CHF

not sure