Basics of HF

Question 1

How can hypervolemia, malnourishment, and pneumothorax lead to pulmonary edema?

Answer 1

Imbalance of Starling Forces

1. Hypervolemia: increased pulmonary capillary pressure
2. Malnourishment: decreased plasma oncotic pressure
3. Pneumothorax: increases the negative intrathoracic pressure acting as a vacuum to draw blood from the pulmonary capillaries

Question 2

Name the 4 determinant of cardiac function

Answer 2

1. HR

SV

2. Contractility
3. Preload
4. Afterload

Question 3

How does a Swan-Ganz catheter (SGC) measure cardiac output?

Answer 3

Thermodilution

• injection of “cooled” fluid thru catheter
• the fluid movement is monitored using a thermometer and used to measure the output

Question 4

What can the Pulmonary Capillary Wedge Pressure (PCWP) tell the physician?

Answer 4

PCWP, under normal conditions, is equal to the LA pressure, end diastolic LV pressure which is the preload.

So PCWP tell us LV preload.

Question 5

What can cause the PCWP to overestimate LV preload?

Answer 5

Anything distal to the balloon (located in the pulmonary arteries) and proximal to the LV that increases pressure.

• mitral stenosis
• Left atrial myxoma
• pulmonary vein obstruction
• positive pressure ventilation (increases alveolar pressure)

Question 6

What can cause the PCWP to underestimate LV preload?

Answer 6

Anything distal to the balloon and proximal to the aorta that decreases pressure.

• noncompliant LV
• high EDLV pressure

Question 7

Pulmonary Artery Diastolic Pressure (PADP) is normally 1-4mmHg greater than PCWP. What affect this relationship or change its consistency?

Answer 7

Severe lung disease can increase the pressure gradient, usually to 5mmHg or more. Pulmonary embolism can change it.

If PCWP is greater than PADP then suspect over-wedging of the catheter balloon.

Question 8

What 4 conditions can make catheter thermodilution to assess CO unreliable?

Answer 8

1. Severe valve insufficiency (need unidirectional flow)
2. Low CO states
3. Irregular rhythm
4. intracardiac shunt

Question 9

What are the 3 steps for managing acute HF?

Answer 9

1. Stabilize: ABCs
2. Identify the cause
3. Treat the cause

Question 10

What is the Tx strategy for chronic HF?

Answer 10

-Neurohormonal modulation
Goals:
-improve QOL (functional capacity, reduce hospitalization)
-improve longterm survival

Question 11

Describe the 4 New York Heart Association functional classifications

Answer 11

Class I: no limitation with ordinary physical activity
Class II: slight limitation with ordinary physical activity
Class III: symtoms with less than ordinary physical activity
Class IV: symptomatic at rest OR w/ any physical activity.

Question 12

Describe the 4 stages of heart failure.

Answer 12

Risk of Heart Failure (A and B)
Stage A: no structural disease
Stage B: asymptomatic structural disease

Heart Failure (C and D)
Stage C: past or current HF symptoms
Stage D: end stage HF