Chapter 10 Part 1 Flashcards
_________ is the number one cause of death in the U.S.
Heart disease
The heart pumps ______ ml or ______ gallons of blood per day
7,500 liters or 2,000 gallons
___________ is the most common mechanism of heart failure
-Contractile (pump failure)
Congestive heart failure
- Venous “congestion”
- Can be due to decreased CO *MC or increased tissue demands
- 5 million Americans are affected
What can cause an increase in tissue demands, leading to congestive heart failure?
- Severe anemia
- Hyperparathyroidism
- Fistula
- “High output failure”
Most common cause of congestive heart failure
Decreased cardiac output
Causes of decreased cardiac output
- Systolic Dysfunction: weak contraction
- Diastolic Dysfunction: failure of relaxation/filling
- Valvular Dysfunction: Stenosis/endocarditis
Risks factors for systolic dysfunction
- Systemic hypertension
- Decreased pH
- CAD
Diastolic dysfunction can lead to:
- Myocardial fibrosis
- Amyloidosis
- Left-sided hypertrophy
- Pericardial tamponade
Two forms of heart failure
- Forward failure
- Backward failure
* Forward failure is almost always combined with backward failure
Forward failure is due to ____________, whereas backward failure is due to __________
- Forward failure (right): insufficient output
- Backward failure (left): venous congestion
Frank-Starling Mechanism
- Myocardial adaptation
- “Compensated heart failure”
- Increased ventricular stretch=stronger contraction
Cost and benefit of the Frank-Starling mechanism
- Benefit: Increased output
- Cost: Increased O2, increased tension
Neurohumoral mechanisms
- Norepinephrine (NE)
- Atrial Natriuretic Peptide (ANP)
What does Norepinephrine do?
- Increase HR
- Increase contractility
- Increase BP (R-A-A system)