Cardio Flashcards
Ischemic heart disease
Imbalance between myocardial oxygen supply and demand resulting in myocardial hypoxia.
Myocardial oxygen supply depends on:
- O2 content:
1) Hemoglobin
2) systemic oxygenation - Coronary blood flow:
1) coronary perfusion pressure - diastolic BP (reduced by hypotension)
2) coronary vascular resistance -
a) external compression: myocardium on coronaries
b) intrinsic regulation: auto-regulation to increase blood flow
Myocardial oxygen demand depends on:
- Ventricular Wall stress (P x r/2h)
Increase pressure causes an increased wall stress which needs and increased oxygen demand. (Hypertension, aortic stenosis) - Heart rate
Increased HR needs more energy and so needs more oxygen. (Exercise, stimulants) - Contractility strength
Increased contraction force needs more energy and therefore more oxygen. (Catecholamines, ionotropic medications)
Intrinsic auto regulation involving metabolic factors:
- Hypoxemia impairs ATP production which increases ADP,AMP which increases adenosine and that causes vasodilation and so increases coronary perfusion.
- Factors like lactate or hydrogen ions can increase perfusion.
Intrinsic auto regulation involving endothelial factors:
- Nitric oxide, prostacyclin, and EDPF are factors that can increase perfusion.
Endothelin 1 is a
Vasoconstrictor
Intrinsic auto regulation involving neural factors:
Alpha adrenergic receptors - vasoconstrict
Beta2 adrenergic receptors - vasodilate
Patho physiology of ischemia
Fixed plaques + abnormal vascular tone -> narrow lumen -> low myocardial supply
Abnormal vascular tone:
1) inappropriate vasoconstriction: dysfunctional endothelium not releasing vasodilators
2) loss of normal anti thrombotic properties:
Dysfunctional endothelium
Factors that reduce myocardial oxygen supply:
Hypotension
Anemia
Massive bleeding
Sepsis
Factors that increase myocardial oxygen demand:
Tachycardia
Arrhythmia
Severe aortic stenosis
Metabolic syndrome:
Having any 3 of:
Hypertension High triglycerides Low HDL cholesterol Diabetes Obesity
What is Acute coronary syndrome and what does it depend on?
Plaque disruption followed by platelet aggregation and thrombus formation
Depends on the degree of blockage and ischemia
Site of atherosclerosis, hypertension, vasculitis:
Atherosclerosis site are the elastic and muscular arteries
Hypertension site are small muscular arteries and arterioles.
Vasculitis affect different vascular segments.
Vasculogenesis occurs in:
Using what factor:
Happens in embryogenesis by VEGF
Angiogenesis, neovascularisation
Occur after maturity in inflammation or in cancers (neoplasia)
Arteriogenesis
Remodeling of existing arteries in response to chronic changes in pressure or flow
Tight endothelial cell junctions can loosen under the influence of:
What does this lead to:
High blood pressure or vasoactive agents (histamine in inflammation)
Flooding of adjacent tissues by electrolytes and protein and even leukocytes can slip between endothelial cells in case of inflammation.
Comment on Endothelial permeability in liver sinusoids, renal glomeruli, and the central nervous system:
Liver and renal are fenestrated
While the CNS is impermeable BBB
Intimal thickening of the vessels happens due to:
1) endothelial cell response
2) vascular smooth muscle response
List the Promoters of proliferative activities of smooth muscles:
PDGF Endothelin-1 Thrombin Fibroblast growth factor Interferon gamma Interleukin 1
List the inhibitors of smooth muscle proliferative activities:
Heparan sulfates
Nitric oxide
TGF-B
Regulators of the smooth muscle proliferative activities include:
RAAS
Catecholamines
Estrogen receptor
Osteopontin which is component of the ECM
What happens to the arteriolar wall with Benign hypertension?
What is the kidney appearance?
Hyaline arteriolosclerosis
The wall is thickened with increased protein deposition (hyalinized) and the lumen is narrowed.
This is chronic
Kidney appears leathery
What impact does benign hypertension have on kidneys?
The kidney get a condition called benign nephrosclerosis due to hypertension.
What happens to the arteriolar wall with the malignant hypertension?
What is the kidney appearance?
Hyperplastic arteriolosclerosis
The smooth-muscle hyperproliferates and produces an onion skin like appearance.
Acute repeated spikes of uncontrolled blood pressure
Kidney appears flea bitten