Ischemic Heart Disease Flashcards
What is IHD?
term given to heart problems caused by narrowed heart (coronary) arteries that supply blood to the heart muscle.( Mismatch between demand and supply)
How does IHD manifest clinically?
- myocardial infarction
- ischemic cardiomyopathy
Why do some deaths due to IHD occur suddenly?
due to acute coronary occlusion
Why do some deaths due to IHD occur overtime?
a period of weeks to years as a result of progressive weakening of the heart pumping process
What is angina in IHD?
- Aching, burning, fullness, heaviness, numbness, pressure, squeezing
- Radiation in arms, back, jaw, neck, shoulder
- High or low BP
•Syncope
-Indigestion or heart burn - mistkane
What are heart rhythm problem in IHD?
- Palpitations (irregular heartbeats or skipped beats)
- Heart murmurs
- Tachycardia (Acute coronary syndrome ACS, Acute myocardial infarction AMI)
- Atrial fibrillation
- Ventricular tachycardia or ventricular fibrillation
- S4gallop
- S3gallop
What is S4 gallop?
A common early finding of diastolic dysfunction
What is S3 gallop?
An indication of reduced left ventricular function and a poor prognostic sign
What are the other important signs and symptoms in IHD?
- Nausea, sweating, fatigue or shortness of breath, weakness or dizziness
- Reduced exertional capacity
- Leg swelling (when left ventricular dysfunction is present)
- Diaphoresis
Is ischemic heart disease the leading cause of death in the world?
yes
Is the distribution of death to IHD different in different countries / income / age?
- yes
- causes are not the same around the world
What is DALY?
- Disability-Adjusted Life Year
- A sum of Years of Life Lost (YLL) and Years Lost to Disability (YLP)
What are the non modifiable risk factors of IHD?
- Age
- Gender
- Family history of CVD
- Ethnicity
- Genetic evidence
- Previous history of CVD
What are the modifiable risk factors of IHD?
- High BP
- Smoking
- Income
- Total cholesterol
- HDL cholesterol / lipoprotein a
- Blood sugar / diabetes / LVH
- BMI
- Diet
- Exercise / physical inactivity
- Stress / mental health
- Alcohol
- Low socio-economic status
- Social deprivation
- Environment
- Certain medication
When does myocardial ischemia occur?
when there is an imbalance between the supply of oxygen ( and other essential myocardial nutrients) and the myocardial demand for these substances
What can coronary blood flow to a region may be reduced due to an obstruction by?
- Atheroma
- Thrombosis
- Spasm
- Embolus
- Coronary ostial stenosis
- Coronary arteritis
When might there just be a general decrease of oxygenated blood flow to myocardium?
- Anaemia
- Carboxyhaemoglobulinaemia
- Hypotension causing decreased coronary perfusion pressure
What is atherosclerosis?
- Complex inflammatory process
- Accumulation of lipids
- Macrophages
- Smooth muscle cells - In the intimal plaques in the large and medium sized coronary arteries
- The process is also called Atherogenesis
What triggers atherogenesis?
- Endothelial dysfunction
- Mechanical sheer stresses (HTN)
- Biochemical abnormalities (elevated and modified LDL, DM, elevated plasma homocysteine)
- Immunological factors (free radicals from smoking)
- Inflammation ( infection such as chlamydia, Helicobacter)
- Genetic alteration
What can a dysfunctional endothelial cells and retention of lipoproteins (LDL, VLDL etc) lead to in the fatty streak phase?
- Increased expression of monocytes interaction (Migration into intimal space)
- Other immune cells that mediate the internalization of LDL to form foam cells
What does the infiltration of the proliferation of tunica media smooth muscle cells lead to in plaque progression?
- Various growth factors e.g. TGF-beta and fibroblast growth factors (FGF) etc
- SMC’s are recruited to the luminal side of the lesion to form a barrier between lesioal prothrombotic factors
What type of fatty things are less likely to regress?
fibrous fatty lesions are less likely to regress than fatty acid
What is the fibrous cap composed of in a stable plauqe?
layers of smooth muscle cells ensconced in a substantial extracellular matrix network
What does a fibrous cap provide?
effective barrier preventing plaque rupture
What do stable plaques have?
small necrotic core
What maintains the fibrous cap?
production of TGF-β by T-reg cells and macrophages maintains fibrous cap quality by being a potent stimulator of collagen production in smooth muscle cell