Hypertension, ischaemic heart disease and cardiac failure

Question 1

What is hypertension?

Answer 1

High blood pressure
Pulmonary= low pressure circulation, systemic= high (common)
Can occur in either or both circulations

Question 2

What is the equation used for blood pressure?

Answer 2

BP= cardiac output x peripheral resistance

Question 3

What are the classifications of systemic hypertension?

Answer 3

Primary vs secondary (based on cause)

Benign vs malignant (based on clinical presentation)

Question 4

What is systematic hypertension?

Answer 4

Sustained resting blood pressure above certain level
140/90 mmHg (depends)
Diastolic pressure determines severity

Question 5

What are the percentages of classification by cause?

Answer 5

Primary= 90% (idiopathic= unknown)
Secondary= 10%
-90% due to renal disease
-10% other causes especially endocrine disease

Question 6

What are the risk factors for systemic hypertension?

Answer 6

Genetic susceptibility
High salt intake
Chronic stress (excessive sympathetic activity)
Abnormalities in renin/ angiotensin- aldosterone
Obesity
Diabetes mellitus
(careful clinical assessment- test the urine!)

Question 7

Causes of secondary systemic hypertension

Answer 7

Renal disease- chronic renal failure polycystic kidneys
Endocrine- pituitary (ACTH), adrenal cortex= glucocorticoid, mineralocorticoid, adrenal medulla= catecholamines
Drug treatment= steroids
Coarctation of aorta

Question 8

What is the difference between benign and malignant hypertension?

Answer 8

Benign= slow changes in vessels and heart with chronic and end-organ dysfunction
Malignant= rapid changes in vessels with acute end-organ dysfunction/ blood pressure tends to be higher

Question 9

Where are-organ effects acting on?

Answer 9

Heart
Kidney
Brain
Vessels (including retina)

Question 10

What are the end-organ effects of the heart?

Answer 10

Left ventricular hypertrophy- fibrosis, arrhythmias
Coronary artery atheroma
Ischaemic heart disease
Cardiac failure

Question 11

What are the end-organ effects of the kidneys?

Answer 11

Nephrosclerosis (drop- out of nephrons = vascular narrowing, proteinuria, chronic renal failure)
Malignant hypertension is associated with acute renal failure

Question 12

What vascular changes lead to benign and malignant hypertension?

Answer 12

Benign= acceleration of atherosclerosis, intimal proliferation and hyalinisation f arteries and arterioles
Malignant hypertension= fibrinoid necrosis

Question 13

Describe ischaemic heart disease

Answer 13

Blood supply to the heart is insufficient for its metabolic demands
Deficient supply- coronary heart disease, reduced coronary artery perfusion (shock, severe aortic valve stenosis)
Excessive demand- pressure overload (hypertension, valve disease)/ volume overload (valve disease)

Question 14

What is coronary artery disease?

Answer 14

Coronary blood flow is normally independent of aortic pressure, initial response to narrowing is compensation
over 75% occlusion leads to ischaemia

Question 15

What are the causes of coronary artery disease?

Answer 15

Atheromatous coronary artery disease= progressive stenosis, haemorrhage into a plaque, thrombosis
Emboli (inflamed aortic valve- endocarditis)
Vasculitis

Question 16

What is a myocardial infarction?

Answer 16

An area of necrosis of heart muscle resulting from reduction (usually sudden) in coronary blood supply

Question 17

What are the causes of MI?

Answer 17

Coronary artery thrombosis
Haemorrhage into a coronary artery plaque
Increase in demand in the presence of ischaemia

Question 18

What are the clinical features of MI?

Answer 18

Central crushing chest pain

Features of heart failure

Question 19

How is an MI diagnosed?

Answer 19

Clinical history
ECG changes
Blood markers- enzymes (creatine kinase), other proteins (troponin)

Question 20

What are the macroscopic and microscopic changes after up to 18 hours after onset of symptoms?

Answer 20

None

Question 21

What are the macroscopic and microscopic changes after 24-48 hours after onset of symptoms?

Answer 21

Macro= pale, oedematous muscle
Micro= oedema, neutrophil infiltration, necrosis of myocytes

Question 22

What are the macroscopic and microscopic changes after 3-7 days after onset of symptoms?

Answer 22

Macro= yellow, rubbery centre with haemorrhagic border
Micro= obvious necrosis and inflammation- early granulation tissue

Question 23

What are the macroscopic and microscopic changes after 1-3 weeks after onset of symptoms?

Answer 23

Macro= infarcted area paler and thinner than unaffected ventricle
Micro= granulation tissue then progressive fibrosis

Question 24

What are the macroscopic and microscopic changes after 3-6 weeks after onset of symptoms?

Answer 24

Macro= silvery scar becoming tough and white
Micro= dense fibrosis

Question 25

Describe right coronary artery obstruction

Answer 25

Inferior infarction ECG changes in leads 2,3 and aVF Can involve posterior septum 30% of cases

Question 26

Describe circumflex artery obstruction

Answer 26

Lateral infraction ECG changes in leads 1 and aVL and lateral chest leads V4-6 20% of cases

Question 27

Describe left anterior descending artery obstruction

Answer 27

Artery of sudden death Anterior infarction ECG changes in anterior chest leads 50% of cases

Question 28

What are the complications, interval and mechanisms of acute MI?

Answer 28

Sudden death- within hours- often ventricular fibrillation Dysrhythmias- first few days- abnormal electrical activity Persistent pain- 12 hours to a few days- progressive necrosis (extension) Angina- immediate or delayed (weeks)- ischaemia of non-infarcted cardiac muscle Cardiac failure- variable- ventricular dysfunction, dysrhythmias

Question 29

Continued complications, interval and mechanisms of acute MI

Answer 29

Mitral incompetence- first few days- papillary muscle dysfunction, necrosis Pericarditis- 2-4 days- inflammation of the pericardium producing sharp chest pain Cardiac rupture- 3-7 days- weakening of wall by necrosis Mural thrombosis- 1 week or more- abnormal endothelial surface Ventricular aneurysm (may rupture)- 4 weeks or more- stretching of newly formed scar tissue

Question 30

Causes of chronic ischaemic heart disease

Answer 30

Chronic angina (exercise induced chest pain) Heart failure (related to reduced myocardial function) Usually widespread coronary artery atheroma Areas of fibrosis often present in the myocardium

Question 31

What is cardiac failure?

Answer 31

Failure of the heart to pump sufficient blood to satisfy metabolic demands Leads to under perfusion which causes fluid retention and increased blood volume Systemic and pulmonary

Question 32

What is acute heart failure?

Answer 32

Rapid onset of symptoms, often with definable cause (MI)

Question 33

What is chronic heart failure?

Answer 33

Slow onset of symptoms, associated with ischaemic or vascular heart disease (for example)

Question 34

What is acute-on-chronic heart failure?

Answer 34

Chronic failure becomes decompensated by an acute event

Question 35

What are the causes of heart failure

Answer 35

- Pressure overload= hypertension (pulmonary or systemic), valve disease (aortic stenosis) - Volume overload= valve disease (aortic incompetence) - Intrinsic cardiac disease= ischaemic heart disease, primary heart muscle disease, myocarditis, pericardial disease, conducting system disorders

Question 36

Examples of valvular heart disease

Answer 36

Bicuspid aortic valve | Senile calcific stenosis

Question 37

Describe Left Ventricular failure

Answer 37

Dominates hypertensive and ischaemic heart failure Causes pulmonary oedema with associated symptoms Leads to pulmonary hypertension and eventually right ventricular failure Combined- congestive cardiac failure

Question 38

Describe right ventricular failure

Answer 38

Causes= secondary to left ventricular failure | Related to intrinsic lung disease- 'cor' pulmonale (chronic obstructive pulmonary disease- COPD)

Question 39

What are the clinical features of forward failure?

Answer 39

Reduced perfusion of tissues | Tends to be more associated with advanced failure

Question 40

What are the clinical features of backward failure?

Answer 40

Due to increased venous pressures Dominated by fluid retention and tissue congestion- pulmonary oedema (left ventricular failure), hepatic congestion and ankle oedema (right)

Question 41

What are the clinical features of left ventricular failure?

Answer 41

Hypotension Pulmonary oedema- paroxysmal nocturnal dyspnoea (severe shortness of breath and coughing that generally occur at night), orthopnoea (breathlessness lying flat), breathlessness on exertion, acute pulmonary oedema with production of frothy fluid

Question 42

What are the clinical features of right ventricular failure?

Answer 42

``` Ankle swelling Hepatic congestion (may be painful) ```