CVR Ischaemic heart disease & hypoxia

Question 1

WHat is IHD?

Answer 1

the term given to heart problems caused by narrowed heart arteries that supply its muscle

Question 2

signs of IHD

Answer 2

• angina (syncope, aching, radiation in arms, high or low BP)
• Heart rhythm problems (palpitations, heart murmurs, tachycardia, atrial fibrillation, S4, S3 gallop from non-compliant ventricle)
• general important symptoms (nausea, sweating, fatigue, shortness of breath diaphoresis, leg swelling)

Question 3

what is the leading cause of death in the world?

Answer 3

IHD

Question 4

where is IHD most prevalent?

Answer 4

eastern europe

Question 5

who is IHD most prevalent amongst?

Answer 5

older people (65+)

Question 6

who is IHD most prevalent amongst?

Answer 6

older people (65+)

Question 7

risk factors types of IHD (2)

Answer 7

modifiable

non modifiable

Question 8

non-modifiable risk factors types of IHD

Answer 8

age, gender. family history CVD. ethnicity. genetic evidence, previous history of CVD

Question 9

modifiable risk factors types of IHD

Answer 9

high BP, cholesterol, smoking, blood sugar/diabetes/LVH, BMI, diet, stress, low socioeconomic state, alcohol, income, certain meds, social deprivation environment

Question 10

causes of IHD

Answer 10

obstruction cause by atheroma. spasms, embolus

Question 11

what is involved in artherosclerosis? (3)

What is the process called?

Answer 11

lipids,
macrophages
smooth muscle cells
-> process is called artherogenesis

Question 12

how do smooth muscle cells interact with plaques?

Answer 12

proliferate and cover plaque. Contains the plaque (lumen of blood vessel reduced)

Question 13

TGF B and T-reg cells and macrophages do what to fibrous cap of stable plaque?

Answer 13

stabilise and protect it

Question 14

when does a plaque become vulnerable?

Answer 14

when the fibrous cap thins

Question 15

when does a plaque become vulnerable?

Answer 15

when the fibrous cap thins

Question 16

presentations of IHD (3)

Answer 16

• asymptomatic
• chronic stable angina (stable fixed plaque)
• unstable angina, non-ST elevation MI, ST elevation MI (unstable plaques)

Question 17

how does an occlusion occur in IHD?

Answer 17

• direct contact with the flowing blood
• blood platelets adhere to it, fibrin deposited, RBC entrapped to form a clot
• clot grows until artery occlude
• can break away e.g. PE

Question 18

what happens to collaterals in sudden event?

Answer 18

doubling by the second/third day

- achieve normal flow within 1 month

Question 19

what happens to collaterals in chronic atherosclerotic patients??

Answer 19

• slow occlusion vessels can develop at the same time while the atherosclerosis become more severe-
• these collaterals can also get damaged
• sometimes hypoxic area is too large

Question 20

soon stages after MI (2)

Answer 20

• small amount of collaterals open
• local blood vessels dilate and cause overfilling with stagnant blood,
  muscle fibres use all remainign O2 -> bloof turns blue brown

Question 21

later stages after MI

Answer 21

vessel wall permeability increases, fluid leak and local tissue oedematous
- cardiac muscle cells swell and no blood supply means they die within a few hours

Question 22

causes of death after MI (4)

Answer 22

• decreased CO (systolic stretch from muscle death and cardiac shock)
• damming of blood in body’s venous system
• ventricular fibrillation
• rupture of infarcted area (Early little danger after few days infarcted area begin to degenerate heart walls become very thin stretched until finally rupture)

Question 23

x

Answer 23

x

Question 24

recovery after an acute MI

Answer 24

• when large area of ischemia:
• > some of centre dies
• > immediate surrounding can recover

Question 25

can CO stay the same after MI?

Answer 25

cardiac resolve means it can

Question 26

how to diagnose IHD?

Answer 26

clinical history, clinical examination, Lab tests, bio markers (b types natiuretic peptide)

Question 27

ECG in stable angina

Answer 27

looks normal

Question 28

ECG in unstable angina

Answer 28

NSTEM - ST depression, T wave inbversion

Question 29

ECG in acute MI/STEMI

Answer 29

ST segment elevation | T wave inversion

Question 30

what does transthoracic eco assess?

Answer 30

- left ventricular function - wall motion abnormalities in the setting of ACS or AMI - mechanical complications of AMI

Question 31

best way to assess coronary arteries

Answer 31

coronary angiography

Question 32

x

Answer 32

x

Question 33

treatment - pharmacological

Answer 33

- HMG-CoA reductase inhibitors e.g. atorvastatin - bile acid sequestrants (increased fecal loss of cholesterol) - calcium channel blockers - ACE inhibitors (esp important for hypertension) - beta blockers for angina to decrease demand of MI O2 - antianginal agent e.g. ranolazine by reducing myocardial cellular and Ca overload. Inhibition of the later Na current of the cardiac action potential - platelet aggregation inhibitors - nitrates

Question 34

treatment - revascularisation therapies

Answer 34

- percutaneous coronary intervention involving stent placement - CABG - vessel from another part of body for blood to bypass blocked artery (when not possible to put stents in)

Question 35

causes of reduced blood flow to a region in IHD

Answer 35

1. Atheroma 2. Thrombosis 3. Spasm 4. Embolus 5. Coronary ostial stenosis 6. Coronary arteritis

Question 36

causes of decreased O2 blood flow to myocardium (3)

Answer 36

- Anaemia - Carboxyhaemoglobulinaemia - Hypotension causing decreased coronary perfusion pressure

Question 37

What triggers artherogenesis? (6)

Answer 37

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

Question 38

serum markers in patients with suspected acute cardiac events

Answer 38

1. Troponins (I or T) 2. Creatine kinase with MB isozymes 3. Lactate dehydrogenase and lactate dehydrogenase isozymes 4. Serum aspartate aminotransferase

Question 39

biomarkers for predicting death in IHD (5)

Answer 39

1. B-type natriuretic peptide 2. CRP 3. Homocysteine 4. Renin 5. Urinary albumin-to-creatinine ratio

Question 40

what is Transoesophageal echocardiography use for?

Answer 40

assessing possible aortic dissection in the setting of AMI.

Question 41

what can Stress echocardiography be used to evaluate

Answer 41

hemodynamically significant stenoses in stable patients who are thought to have CAD.

Question 42

procedure of coronary angiography

Answer 42

- Iodinated contrast agent is injected through a catheter placed at the ostium of the coronaries. - The contrast agent is then visualized through radiographic fluoroscopic examination of the heart. - Coronary angiography remains gold standard for detecting stenoses that may be revascularized through percutaneous or surgical intervention

Question 43

What is coronary CT angiography an important tool in?

Answer 43

Detecting the presence and extent of CAD and independent predictors of significant coronary stenosis and other cardiovascular events

Question 44

Pros of performing ultrasonography on the common and internal carotid arteries

Answer 44

- a noninvasive measure of arterial wall anatomy | - may be performed repeatedly and reliably in asymptomatic individuals.

Question 45

what is the most widely applied technqiue for measuring coronary flow in humans

Answer 45

Doppler Velocity probes - It helps evaluating whether normal blood flow has been restored after percutaneous transluminal coronary angioplasty (PTCA).

Question 46

How does Doppler Velocity probes work?

Answer 46

Doppler guidewire measures phasic flow velocity patterns and tracks linearly with flow rates in small, straight coronary arteries.

Question 47

Example of bile acid sequestrants

Answer 47

Cholestyramine (Questran, LoCholest, Prevalite)

Question 48

how do Ca channel blockers work?

Answer 48

amlodipine (Norvasc) relaxes coronary smooth muscle and produces coronary vasodilation, which in turn improves myocardial oxygen delivery. Amlodipine (Norvasc)

Question 49

examples of ACE inhibitors

Answer 49

Captopril (Capoten), enalapril (Vasotec), and lisinopril (Zestril).

Question 50

what does percutaneous coronary intervention involve?

Answer 50

Involves angiography and stent placement: Common to treat stable CAD Improves blood flow by placing a stent and compressing the plaque

Question 51

What does CABG involve?

Answer 51

A vessel from another part of your body to create a graft that allows blood to flow around the blocked or narrowed coronary artery. This type of open-heart surgery is usually used only for people who have several narrowed coronary arteries.

Question 52

Recommendations from WHO for reducing risk of CHD

Answer 52

``` - Take moderate physical activity for a total of 30 minutes on most days of the week. - Avoid tobacco use and exposure to environmental smoke; make plans to quit if you already smoke. - Choose a diet rich in fruits, vegetables and potassium, and avoid saturated fats and calorie-dense meals. - Maintain a normal body weight; if you are overweight, lose weight by increasing physical activity and reducing calorie intake. - Reduce stress at home and at work. ```