Atherosclerosis- Modifiable Risk Factors
- Secondary hyperlipidemia (alcohol, beta-andrenergic medications, diuretics),
- smoking,
- hypertension,
- diabetes,
- obesity
- Hypothyroidism
- Nephrotic syndrome
Atherosclerosis- Definition
Fibrous thickening of large and medium sized vessels due to lipid plaques- calcification
Atherosclerosis- Non-modifiable risk factors
- Male gender (females after menopause)
- Family Hx (stroke, ischemia)
- Primary hyperlipidemia (lipase deficiencies)
- High lipoprotein(a)
- Elevated homocysteine
Preload
- End diastolic pressure.
- Initial stretching of cardiomyocytes prior to contraction.
- Affected by venous BP & rate of return
Afterload
- Tension in left ventricle during ejection
- Aortic pressure L ventricle must overcome to eject blood.
Stroke volume
End diastolic pressure - end systolic pressure
- Influenced by preload, after load and changes in sympathetic input
Cardiac output
Stroke volume x HR
Frank Starling Law
Increase in EDV-> increased contraction-> return to ESV
- What comes in goes out
- Independent of ANS - Due to change in overlap of muscle fibers
Ejection fraction
- EF= stroke volume/ EDV
- measure of blood leaving heart at contraction
- 50-75% at rest
- measure of systolic function
- Low EF = failing heart
Ejection fraction-> increased EDV
- Increase EDV = increase EF due to Frank- starling mechanism
Ejection fraction-> increase contractility
Increased contractility = increased EF.
Due to more complete section of EDV
Contractility
Strength of contraction at any given EDV
End systolic volume
volume of blood in ventricle following contraction
End systolic fraction
Increases with increase in stroke volume without increase in contractility
