Cardiovascular physiology Flashcards
1
Q
Left ventricular ejection fraction?
A
- Left ventricular ejection fraction = (stroke volume / end diastolic LV volume ) * 100%
- Stroke volume = end diastolic LV volume - end systolic LV volume
2
Q
Pulse pressure?
A
- Pulse pressure = Systolic Pressure - Diastolic Pressure
- Factors which increase pulse pressure a less compliant aorta (this tends to occur with advancing age)
- increased stroke volume
3
Q
Pathophysiology?
A
Ischaemic heart disease is a complex process that develops over a number of years:
- initial endothelial dysfunction is triggered by factors such as smoking, hypertension and hyperglycaemia
- results in changes to the endothelium - pro-inflammatory, pro-oxidant, proliferative and reduced nitric oxide bioavailability
- fatty infiltration of the subendothelial space by low-density lipoprotein (LDL) particles
- monocytes migrate from the blood and differentiate into macrophages. Macrophages then phagocytose oxidized LDL, turning into large ‘foam cells’.
- these macrophages die resulting in further propagation of the inflammatory process.
- smooth muscle proliferation and migration from the tunica media into the intima results in formation of a fibrous capsule covering the fatty plaque.
4
Q
Slide showing a markedly narrowed coronary artery secondary to atherosclerosis. Stained with Masson’s trichrome.
A
Diagram showing the progression of atherosclerosis in the coronary arteries with associated complications on the right.
5
Q
Complications of atherosclerosis?
A
- Once a plaque has formed a number of complications can develop:
- the plaque forms a physical blockage in the lumen of the coronary artery.
- This may cause reduced blood flow and hence oxygen to the myocardium, particularly at times of increased demand, resulting clinically in angina
- the plaque may rupture, potentially causing a complete occlusion of the coronary artery. This may result in a myocardial infarction
