T3 - Heart failure

Question 1

what is heart failure the impaired ability of?

Answer 1

ventricular ejection (systolic) and filling (diastolic)

Question 2

what is the CO equation?

Answer 2

CO = HR x SV

Question 3

what is stroke volume?

Answer 3

amount of blood pumped out the LV per beat

Question 4

what is something that would increase preload?

Answer 4

increased blood volume and vasoconstriction

Question 5

what is something that would decrease preload?

Answer 5

vasodilation and decreased blood volume

Question 6

what is pre load?

Answer 6

pressure the heart is under before it contracts (volume of blood stretching the cardiomyocytes at the end of diastole)

Question 7

what is after load

Answer 7

resistance the heart must work against to eject blood

Question 8

in what situation will there be a decreased CO even though HR is high and why?

Answer 8

arrhythmia

- not enough time for ventricular filling therefore decreased stroke volume and cardiac output

Question 9

what describes the relationship between preload and CO?

Answer 9

frank starling law

Question 10

describe how a large increase in preload can decrease cardiac output

Answer 10

cardiomyocytes can be too much which reduces in less contraction and therefore less cardiac output and less stroke volume

Question 11

what is high output heart failure?

Answer 11

heart function is normal but cant meet high body demands (due to a medical condition)

Question 12

what can cause high output heart failure?

Answer 12

thyrotoxicosis (lots of thyroid hormones), anaemia, pregnancy, pagers disease, acromegaly, sepsis

Question 13

what are the two types of low output heart failure?

Answer 13

systolic and diastolic

Question 14

what is systolic heart failure and what are the three main causes?

Answer 14

progressive deterioration of myocardial function

- caused by ischaemic injury, volume overload and pressure overload

Question 15

what is diastolic heart failure?

Answer 15

inability of the chamber to relax or expand and fill during diastole to reach an adequate blood volume

Question 16

what type of heart failure has a normal ejection fraction but cant fill properly?

Answer 16

low output diastolic heart failure

Question 17

what are four causes of diastolic heart failure?

Answer 17

LV hypertrophy, infiltrative disorders, constrictive pericarditis, restrictive cardiomyopathies

Question 18

give five broad causes of heart failure

Answer 18

coronary heart disease, hypertensive heart disease, valvular heart disease, myocardial disease/cardiomyopathy or congenital heart disease

Question 19

what is a cardiomyopathy?

Answer 19

diffuse disease of heart muscle that leads to functional impairment

Question 20

how is cardiomyopathy characterised?

Answer 20

• heart muscle of stretched, thick or stiff

- dilated hypertrophic or restrictive

Question 21

what proportion of dilated cardiomyopathies are familial and what does this cause?

Answer 21

50% are familial and this triggers T cell mediated inflammation in the heart

Question 22

what type of cardiomyopathy can myocarditis cause?

Answer 22

dilated CM

Question 23

what type of cardiomyopathy is caused by amyloid and what does this result in?

Answer 23

restrictive CM

- results in stiff walls and impaired filling

Question 24

what are the three compensation mechanisms in HF that maintain arterial pressure and perfusion to organs?

Answer 24

1) frank starling - vasoconstriction to increase venous return therefore increasing preload, stretch and FOC
2) myocardial structure change - hypertrophy
3) neurohumoral system - NA release increases HR and FOC, atrial and B type naturietic peptide increase HR as well as activating RAAS

Question 25

what stimulates activation of the RAAS?

Answer 25

low CO and therefore low BP

Question 26

what does activation of the RAAS cause?

Answer 26

- increased sympathetic input | - increased aldosterone which therefore increases Na+ retention and vasoconstriction - not good in HF

Question 27

what three compensatory mechanisms from a normal healthy heart can worsen HF?

Answer 27

- vasoconstriction - increases resistance heart pumps against therefore increasing after load and decreasing CO - Na/H20 retention (via aldosterone) - increase in fluid volume increases preload which increases stretch in the heart which decreases FOC and CO - tachycardia - decreases diastolic filling time therefore decreased ventricular filling therefore reducing SV and CO

Question 28

what does pressure overload cause?

Answer 28

- concentric left ventricular hypertrophy - stretched muscle therefore decreased cavity diameter - thick walls and lower atrial/ventricular volume

Question 29

what does volume overload cause?

Answer 29

- chamber dilation with increased ventricular pressure - deposition of new sarcomeres with increased length and width - very dilated ventricles with thin muscular walls but increased muscle mass in proportion to chamber diameter

Question 30

what causes pressure overload?

Answer 30

high blood pressure or aortic stenosis

Question 31

what causes volume overload?

Answer 31

mitral or aortic regurgitation

Question 32

what three ways can heart failure be categorised?

Answer 32

- which side (L, R or biventricular) - acute or chronic - compensated (handle compensation mechanisms with treatment) or decompensated (previously compensated now unwell again)

Question 33

where does the back up of blood come from that causes LHS HF and where does this cause congestion?

Answer 33

back up of blood from LA which goes back into pulmonary circulation causing congestion in the lungs

Question 34

what are four causes of LS HF?

Answer 34

iscahemic heart disease, valvular heart disease, hypertension and myocardial disease

Question 35

what does pulmonary congestion due to LSHF result in (O2 diffusion distance)?

Answer 35

increased O2 diffusion distance, harder to breathe and wet lungs

Question 36

what are the symptoms of wet lungs due to LSHF?

Answer 36

dyspnoea on exertion, orthopnea (relieved by sitting or standing), paroxysmal nocturnal dyspnoea

Question 37

what effect does LSHF have on the kidneys?

Answer 37

lower CO means lower renal perfusion which causes activation of RAAS - increased aldosterone and Na+ retention - increased blood volume and interstitial fluid

Question 38

what are the brain symptoms from LSHF?

Answer 38

- less specific - hypoxic encephalopathy (brain injury due to O2 deprivation) - irritability/attention loss - restlessness - coma

Question 39

what is the main cause of RSHF?

Answer 39

LSHF (congestive)

Question 40

what is cor pulmonale and what causes it?

Answer 40

enlargement of the RHS of the heart due to lung disease | - often caused by respiratory disease eg COPD or PE

Question 41

apart from cor pulmonale, what are two other causes of RSHF?

Answer 41

valvular heart disease and congenital heart disease

Question 42

what effect does RSHF have on the i) liver ii) spleen iii) abdomen iv) subcutaneous tissue v) pleura and pericardium

Answer 42

``` I) congestive hepatomegaly, lobar necrosis and cardiac cirrhosis ii) congestive splenomegaly iii) ascites iv) oedema v) effusions (anything with lots of fluid) ```

Question 43

what are the two causes of biventricular heart failure?

Answer 43

1) same pathological process on each side of the heart | 2) as a consequence of LSHF - volume overload in the pulmonary circulation which causes RSHF

Question 44

what is the clinical presentation of biventricular HF?

Answer 44

- excess fluid accumulation (dyspnoea, orthopnea, oedema, ascites) - reduced CO causing fatigue and weakness

Question 45

what are 10 clinical signs of HF

Answer 45

- cool/pale/cyanotic extremities - tachycardia due to increased sympathetic activity - elevated JVP - 3rd heart sound (galloping) - displaced apex due to LV enlargement - crackles or decreased breath sounds - ascities - peripheral oedema - hepatomegaly

Question 46

what can be measured when testing for HF?

Answer 46

NT-pro BMP levels - if normal it probably isn't HF