Heart failure and BNP

Question 1

BNP physiological mechanism

Answer 1

1. REDUCE SYSTEMIC VASCULAR RESISTANCE THEREBY REDUCE AFTERLOAD
   - ACT VIA ANP RECEPTORS SO EFFECTS ARE THE SAME AS ANP
2. Renal : dilates the afferent glomerular arterioles and constricts efferent glomerular arterioles increasing GFR
   - inhibits renin secretion by RAAS
3. Adrenal - reduces aldosterone secretion by zona glomerulosa of adrenal cortex
4. relaxes vascular smooth muscles - systemic vasodilation

Question 2

BNP DEFINITION

Answer 2

1, Brain natriuretic peptide is a hormone secreted by cardio myocytes in the heart ventricles in response to stretching caused by increased ventricular volume

Question 3

ANP

Answer 3

1. synthesized and secreted by atria in response to increased blood volume
2. both ANP and BNP act via ANP receptors so same effect on the body

Question 4

BNP vs NT-proBNP

Answer 4

proBNP is cleaved to form:

1. BNP
   - biologically active
   - 20 min half life
   - labile
   - higher in healthy females
2. NT-proBNP
   - 60 - 120 min half life
   - stable
   - increases with age

Question 5

Factors that increase BNP/NT-proBNP

Answer 5

1. tachycardia / ischameia / acute coronar syndrome
2. liver cirrhosis
3. renal impairment
4. Sepsis
5. COPD
6. Exercise

Question 6

Factors that decrease BNP/NT-proBNP

Answer 6

1. Obesity
2. Ace inhibitors
3. Angiotensin receptor blockers
4. Aldosterone antagonists
5. Diuretics

Question 7

BNP values normal and raised

Answer 7

normal < 100 ng/L

raised > 100 ng/L

Question 8

NT-proBNP values normal and raised

Answer 8

normal < 300 ng/L

raised > 300 ng/L

Question 9

definition of heart failure

Answer 9

1. Heart failure is when the heart is unable to supply blood to meet the body’s demand

Question 10

two major types of heart failure are;

Answer 10

1. Systolic heart failure - the heart can’t pump hard enough to meet the body’s demands
2. Diastolic heart failure - not enough blood fills into the heart

Question 11

definition of cardiac output

Answer 11

the volume of blood ejected per minute

2. CO = beats per minute x volume of blood per beat

Question 12

definition of ejection fraction

Answer 12

Stroke volume / Total volume

1. 50-70% - normal ejection fraction
2. 40% - 50% - borderline
3. < 40 % - systolic heart failure

Question 13

properties of diastolic heart failure

Answer 13

the heart is not filling enough

1. stroke volume is low
2. total volume filled up in the ventricles is also low
3. therefore ; ejection fraction is normal !

Question 14

Laplace’s law

Answer 14

1. the pressure within the radius of the heart is = tension around the wall of the heart
2. increase in preload = increase in radius
3. ventricles dilate and remodelled so it stays dilated and easy to dilate further
4. same pressure over a greater radius -> increased tension around the wall of the heart ->the more it is stretched -> easier it is to dilate further

Question 15

How are the stages of heart failure determined?

Answer 15

1. New York heart association classification

2. 4 main stages of heart failure

Question 16

NYHA Class 1

Answer 16

1. no limitations of physical activity
2. physical activity doesn’t cause ;
   - breathlessness
   - fatigue
   - palpitations

Question 17

NYHA Class II

Answer 17

1. slight limitation of physical acitivity
2. comfortable at reast but ordinary physical activity can cause;
   - breathlessness/fatigue/palpiations

Question 18

NYHA Class III

Answer 18

1. Marked limitation of physical activity
2. Comfortable at rest but less than ordinary physical activity can cause;
   - breathlessness/fatigue/palp

Question 19

NYHA Class IV

Answer 19

1. unable to carry on any physical activity without discomfort
2. Symptoms present at rest
3. Any physical activity can result in discomfort and fatigue

Question 20

Symptoms of right sided heart failure

Answer 20

1. awakening at night with shortness of breath
2. shortness of breath during exercise
3. shortness of breath lying flat (orthopnea)
4. coughing/ wheezing
5. fluid retention - swelling of ankles, legs and feet
6. increased urge to urinate especially at night due to congestion of renal arteries and renal veins

Question 21

Symptoms of left sided heart failure

Answer 21

1. shortness of breath
2. chronic lack of energy - due to disturbed ability to respire as a result of pulmonary oedema
3. Difficulty sleeping at night due to breathing problems
4. Cough with frothy sputum
5. Confusion + impaired memory
6. Pulmonary oedema -> hypoxia

Question 22

Management of heart failure

Answer 22

1. Signs + Symptoms suggestive of HF
2. Clinical examination ( fbc, fasting blood glucose, serum urea)
3. BNP levels tested ( or ECG if no BNP)
   - (BNP levels > 100) —> Heart failure is possible
4. Refer to ECHO if BNP raised
   ECHO : LVEF < 40
5. Do ECG if not already done to determine the cause of heart failure

Question 23

Chest X ray in heart failure

Answer 23

1. Kerley B lines
2. Prominent vasculature
3. Cardiomegaly
4. Upper lobe division - blood vessels are congested so can see upper lobes clearly

Question 24

First line in heart failure

Answer 24

1. Beta blockers AND Ace inhibitors
   ( if intolerant to ACE inhibitors give ARBS)

• Ace inhibitors inhibit angiotensin converting enzyme which is responsible for breaking down bradykinin,
• more bradykinin -> vasodilation + gives a dry cough

Question 25

Side effects of ace inhibitors

Answer 25

1. low bp 2. high potassium - 3. renal failure - acts to distrupt RAAS 4. dry cough 5. hypoglycaemia

Question 26

contraindic to ace inhibitors

Answer 26

1. angio oedema 2. bilateral renal artery stenosis 3. pregnancy

Question 27

names of ace inhibitors

Answer 27

1. Rampiril 2. Lisinopril 3. Losartan 4. Candesartan

Question 28

Second line in Heart Failure

Answer 28

1. Mineralcorticoid receptor antagonist 2. ACE/ARB 3. Beta blocker

Question 29

Third line in Heart failure

Answer 29

1. Sacubritil/Valsartan ( ERNESTO ) 2. Mineralcorticoid receptor antagonist 3. Beta blocker ( DISCONTINUE ARB/ACEI )

Question 30

Fourth line in Heart Failure

Answer 30

1. ICD - implantable cardiac defibrillator ( pacemaker w defib function ) OR - Cardiac resychronisation therapy generator - inputs voltage into sinoatrial node - used only if cardiac conduction shows LBBB or prolonged QRS complex, to ensure ventricles are well coordinated 2. Ivabradine

Question 31

Fifth line in Heart Failure

Answer 31

1. Digoxin | 2. Hydralazine/Isosorbide dinitrate if intolerant to ace inhibitors/ARBs/SacubritilVasartan)

Question 32

6th line in Heart failure

Answer 32

CARDIAC TRANSPLANT

Question 33

Ivabradine - mechanism of action

Answer 33

1. used if heart rate is > 75 on beta blockers and still have symptoms 2. Inhibits 'f' funny channels in the heart and reduces the amount of potassium entering the cell - slows down repolarisation - heart rate reduction 3. reduces symptoms but does not reduce mortality 4. Side effects - slow heart rate/ low bp/ AF

Question 34

Adjuncts to reduce risk in HF

Answer 34

1. Opiods - peripheral vasodilation and pain relief 2. Statin - reduces cholesterol 3. Asprin - inhibits thromboxane and reduces tendency to clot 4. Warfarin - patients who have AF 5. Amlodapine - calcium channel blocker to reduce blood pressure if still high 6. Iron (if anemic)

Question 35

Hydralazine/Isosorbides dinitrate

Answer 35

1. used in patients intolerant to ace inhibitors/arbs/sacubritil+valsartan 2. increases circulating NO in the blood which is responsible for vasodilation 3. increases capacity of blood around the body 4. decreases preload

Question 36

Entresto - Sacubritil/Valsartan

Answer 36

1. used in the place of ace inhibitors + angiotensin receptor blockers 2. sacubritil blocks Neprilysin enzyme which is responsible for breaking down acute phase proteins and naturetic peptides 3. increase in ANP/BNP/Bradykinin etc 4. RESULTS - - decreases sympathetic tone - vasodilation - lowers blood pressure

Question 37

Beta blockers

Answer 37

1. blocks beta receptors 2. Bisoprolol + Carvedilol + Metoprolol 3. Side effect - lowers HR/reduces BP/postural hypotension 4. Contraindic - - asthma : B1 can be non selective if at high enough doee - 2nd + 3rd degree AV block

Question 38

Mineral receptor corticoids

Answer 38

1. also known as aldosterone antagonists / Potassium sparing diuretics 2. Reduces production of Na/K ATPASE pumps and thus reduces water retention 3. leads to reduced preload 4. Spirnolactone / Epleronone 5. side effects - - Low BP - High potassium - renal dysfunction

Question 39

Cardiac surgery options

Answer 39

1. cardiac transplant | 2. Left ventricular assist device - helps pump blood out of the left ventricle into the aorta

Question 40

Symptomatic treatment

Answer 40

1. Diuretics 2. Digoxin 3. Ivabradine

Question 41

Treatment to reduce CVS risk factors

Answer 41

1. Statins 2. Antithrombolytics 3. Antihypertensives 4. Iron if anaemic

Question 42

Digoxin

Answer 42

1. cardiac myocytes increase uptake of calcium to increase power and contractility of the muscle 2. eliminate K+ from cardiac myocytes to increase time for repolarisation thus slow down the heart rate - inc stroke vol + reduces work of heart 3, Toxicity of digoxin - can cause disturbance of colour vision/tachycardia or decrease of heart rate / abdo pain - Antidote - Digibind to counteract these effects