238 - Heart Failure

Question 1

What is heart failure?

Answer 1

Failure to maintain cardiac output to meet the bodies O2 demands despite adequate venous return/pressures

Question 2

What investigations can be done in ? Heart failure?

Answer 2

ECG - if normal - probably not HF
CXR - specific signs
Bloods - Brain Natiuretic peptide
Echocardiocram
Perfusion Scintigraphy

Question 3

What sings are seen on CXR with someone with heart failure/

Answer 3

Cardiomegaly
Pleural effusion
Pulmonary oedema 
Kerley's B lines
Pulmonary venous congestion

Question 4

What function does testing Brain natiuretic peptide have?

Answer 4

Levels increase with myocardial wall stress

A low value has a high negative predictive value for HF

Question 5

What might you seen on an echocardiogram in HF

Answer 5

LV or RV - dilated, reduced contractility
Valve lesions?
Mechanical dysfunction

Question 6

What does perfusion scintigraphy do?

Answer 6

Looks for coronary artery disease

Stress heart with a drug - inject radioactive dye, scan with a gamma camera - shows blood flow + scarring

Question 7

Heart failure can be classified many ways, what are they?

Answer 7

Left vs right sided

Systolic vs Diastolic

How output vs high output

Question 8

Describe Left sided HF

Sympt, signs, why?

Answer 8

Pulmonary venous congestion

Sympt: Dyspnoea, orthopnoea, paroxysmal nocturnal dyspnoea, fatigue.

Signs: displaced apex beat, S3/S4/Gallop rhythm, basal insiratory crepitations

Why? 70% ischaemic heart disease
10% valvular heart disease
10% cardiomyopathy

Can be due to Bp, toxic, diabetic, sepsis

Question 9

Describe Right sided heart failure

Answer 9

Systemic venous congestion

Symp: Peripheral oedema, Raised JVP, Hepatomegaly, ascites.

Why? Chronic lung disease -> Cor pulmonale, pulmonary hypertension, L-R cardiac shunts, chronic valvular disease

Question 10

What is CCF?

Answer 10

Congestive Cardiac Failure

L and R heart failure combined

Question 11

What heart sound is pathonemonic of heart failure?

Answer 11

a 3rd hear sound - sounds like gallop rhythm

Question 12

Describe systolic HF

Answer 12

HF symptoms with Left ventricular systolic dysfunction and reduced pump function

a reduced ejection fraction of

Question 13

Describe diastolic HF

Answer 13

HF symptoms with a preserved LV systolic function

Normal heart size but LA increased in size, LV wall thickened - so the ventricle can’t relax enough as it is too stiff -> less filling.

Question 14

What is low output heart failure?

Answer 14

Most HF is low output

CO is reduced and fails to increase normally with exertion

Due to pump failure, excessive preload or chronic excessive afterload

Question 15

What is high output heart failure?

Answer 15

Rare

When CO is normal or increased, but faced with very high needs - so failure because CO can’t meet those excessive needs.

A mimic of heart failure - eg. anaemia, septicaemia, liver failure, beri beri, AV shunt

• look for reversible causes

Question 16

What lifestyle management options are there in heart failure?

Answer 16

Patient education key
Monitor weight (for oedema)
Sodium restriction
Fluid restriction
Reduce alcohol
Moderate daily exercise

Question 17

What disease modifying medication is available in heart failure?

Answer 17

1st) ACEinhibitor + Beta-Blokers
2nd) if intollerant try ARBs - angiotensin II receptor antagonists
3rd) if intollerant try Isorobide dinitrate + hydralazine

Then: If symptoms persist add in:

• Spironolactone
• Ivabridine

Question 18

Which ACE inhibitors are used in HF?

Answer 18

Ramipril, captopril

Question 19

What do ACEi do in HF?

Answer 19

They improve symptoms and improve LV function and increase survival + reduce hospitalisation

Question 20

Who are ACEi contra-indicated in?

Answer 20

Severe AS/MS/LVOT
bilateral renal stenosis
Pregnancy
If Creat >220

Question 21

What side effects do ACEi have? Why?

Answer 21

Hypotension

Cough (also blocks bradykinin which supresses cough normally)

Question 22

Which B-Blockers are used in heart failure?

Answer 22

Bisoprolol
Cavedilol

Reduces mortality by 30%

Question 23

Which ARBs are used in Heart failure?

Answer 23

Candestartan
Valsartan

• don’t give a cough s/e so good if can’t cope with ACEi

Question 24

What does spironolactone do in HF?

Answer 24

A K+ sparing diuretic, acts as an aldosterone antagonist.

It is cardioprotective, and reduces mortality and hospitilisation

Question 25

What is a side effect of spironolactone?

Answer 25

Gynecomastia
Breast pain
High K+

Question 26

How does Ivabridine work?

Answer 26

Inhibits If channel in the sinus node - reduces HR.
Reduces hospitalisation but not mortality
Good for QoL

Question 27

What are some symptom relieving medications that can be used in HF?

Answer 27

Loop diuretics (Furosemide, Bumetanide) - Act on ascending loop of henle

Digoxin - improves filling by slowing down conduction pathways in the AV node - reduces ventricular rate

Question 28

What surgery could be done for someone with HF?

Answer 28

Cardiac resynchronisation - CRT-P
+ a defib - CRT-D

Synchronises inter and intra ventricular contraction in HF

Question 29

What determins cardiac output?

Answer 29

CO = HR x SV

SV is determined by contractility + preload, and negatively affected by afterload.

Question 30

What is afterload?

Answer 30

Ventricular wall tension during systole

Increases if arterial pressure increases

Question 31

How do calcium changes damage muscle function in heart failure?

Answer 31

Normally Ca is released from stores and influx - which causes contraction. Ca is then pumped back out again into the stores by a co-transporter

In failure - There is reduced Ca movement, and reduced Ca in stores - so less is released. So there is less energy in each contraction.
There is also impaired reuptake after each contraction - so the muscle relaxes poorly
- so dysfunction in contraction and preload.

Question 32

What is the cardiac function curve?

Answer 32

Flow plotted against central venous pressure - gives you CO as the curve.

Developed by starling - isolated heart-lung preparations.
- examined the effects of change in filling pressure on output.

Why is the curve that shape? The myocytes contract following an isometric length-tension curve - so same shape.

Question 33

What are gyton curves?

Answer 33

Cardiac function curve with a venous return curve combined - Where they intersect is the CO.

Question 34

In HF the heart compensates -what is the Frank starling mechanism ?

Answer 34

Frank starling mechanism - SV increases with increased volume of blood filling (end diastolic volume)

• this shifts the curve up slightly - helps increase CO in early heart failure

Question 35

In HF the heart compensates - explain what happens to the ventrical

Answer 35

Ventricular hypertrophy and remodelling - concentric and eccentric hypertrophy increases the ventricular volume

BUT in longrun harmful

Question 36

Why is ventricular hypertrophy bad in the long run in HF?

Answer 36

It causes decompensation

The failing heart has to push against increased total peripheral resistance.

Due to Laplace’s law - T=Pr/2
As the radius increases you require more tension to produce the necessary pressure.

The AV valve also becomes too small - get leakage

Question 37

Describe the neurohumoral activation that occurs in heart failure

Answer 37

A reduced CO causes:
- Increase in sympathetic activation -> increase in contractility and HR - increase CO

• RAAS -> vasoconstriction: arteriolar increases Bp, venous increases venous return -> increases preload
• also redustribution of resting CO - more to brain
• ADH increases - increases circulating volume - increases venous return

Question 38

Why do the neurohumoral adaptations in heart failure harmful in the long term?

Answer 38

Volume expansion -> oedema
R failure - Peripheral oedema
L failure - pulmonary oedema -> conjections on pul veins and cap

Ventricular arrythmias can also be caused by re-entry circuits (DAD mediated?)