Cardiology NMS

Question 1

What is CHF

Answer 1

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

Question 2

Systole is governed by what 3 cardiac properties

Answer 2

Contractility
Afterload
preload

Question 3

What is preload

Answer 3

the sarcomere stretch before contraction

Question 4

What property of dysfunction is associated with most cases of CHF

Answer 4

decreased contractility

Question 5

What are the causes of decreased contractility

Answer 5

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

Question 6

How can afterload be quantified

Answer 6

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

Question 7

What is the frank-starling mechanism

Answer 7

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.

Question 8

What governs diastolic function

Answer 8

active and passive properties

Question 9

What is the active property of diastolic function

Answer 9

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

Question 10

What is the passive property of diastole

Answer 10

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

Question 11

What is the formula for stiffness

Answer 11

(delta P) / (delta V)

Question 12

What causes an increased in stiffness

Answer 12

Hypertension

Amyloid

Question 13

What are the types of heart failure

Answer 13

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

Question 14

What are some causes of high output HF

Answer 14

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

Question 15

Discuss how chronic anemia leads to high output HF

Answer 15

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.

Question 16

What three things will lead to volume overload

Answer 16

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

Question 17

What is the most common cause of Right sided failure

Answer 17

left sided failure.

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

Question 18

What are the symptoms of CHF

Answer 18

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

Question 19

How does CHF cause nocturia

Answer 19

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.

Question 20

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

Answer 20

RIGHT SIDE

Question 21

What causes edema associated with cardiac

Answer 21

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

Question 22

What are the physical signs of CHF

Answer 22

not sure