heart failure

Question 1

what is heart failure?

Answer 1

marked reduction in ventricular contractility

Question 2

prognosis of heart failure

Answer 2

high mortality

50% death within 5 years

Question 3

how to calculate stroke volume?

Answer 3

left ventricular end diastolic volume - left ventricular end systolic volume

Question 4

average systolic volume

Answer 4

70ml

Question 5

average cardiac output

Answer 5

5L/min

Question 6

what is ejection fraction?

Answer 6

the proportion of the left ventricular end diastolic volume that is ejected. Measures how effective the heart is as a pump

Question 7

normal ejection fraction

Answer 7

70%

Question 8

how to calculate ejection fraction

Answer 8

stroke volume/left ventricular end diastolic volume

Question 9

ejection fraction in heart failure

Answer 9

reduced to below 60%
affects tissue perfusion
unable to sustain adequate circulation of blood to the tissues

Question 10

which side of the heart more commonly fails?

Answer 10

left because of higher resistance to pump against

higher workload

Question 11

pressure volume relationship left ventricular work

Answer 11

area under the curve

Question 12

aspects to left ventricular pressure-volume relationship

Answer 12

1. filling

2. ejecting

Question 13

filling of left ventricle

Answer 13

diastolic compliance - how well it fills
healthy heart is very compliant
limited by pericardium

Question 14

ejecting of left ventricle

Answer 14

systolic contraction - strength of contraction

Question 15

contractility of left ventricle

Answer 15

more stretched the myocardium the more it will recoil and eject harder
limited by overlap of myocardial filaments
greater contact of actin/myosin interaction and increased sensitivity of myofibrils to Ca2+ affects systolic contraction ability

Question 16

what are the types of heart failure?

Answer 16

systolic or diastolic dysfunction

Question 17

systolic dysfunction definition

Answer 17

heart failure with reduced ejection fraction

Question 18

diastolic dysfunction

Answer 18

heart failure with preserved ejection fraction

Question 19

features of systolic dysfunction

Answer 19

impaired myocardial contraction so heart cannot empty properly
flabby, weak ventricle
systolic contraction falls
stroke volume falls
to compensate and maintain cardiac output tachycardia which puts more pressure on heart long-term

Question 20

features of diastolic dysfunction

Answer 20

impaired myocardial relaxation so heart cannot fill properly
stiff fibrotic ventricle - cardiomyopathy and collagen deposits
diastolic compliance drops
high pressures at lower volumes of filling
left ventricular end diastolic pressure rises
stroke volume falls
compensation increases systolic contraction
increased pressure on heart

Question 21

upstream effects of heart failure

Answer 21

inability to keep up with returning venous flow so increased upstream pressure in circulation
increased pressure in lungs

Question 22

downstream effects of heart failure

Answer 22

inadequate perfusion of vital organs - kidneys
reduced perfusion of kidneys sensed by juxtaglomerular apparatus
activation of RAAS
vasoconstriction increases SVR and BP
ADH release
aldosterone release
water and sodium retention
blood volume increased despite normal blood volume in response to reduced perfusion

Question 23

what happens to stroke volume?

Answer 23

decreased due to increased afterload and SVR from vasoconstriction

Question 24

effect of rise in upstream pressure in heart failure

Answer 24

hydrostatic pressure increased due to increases blood volume so increased loss of fluid from circulation into interstitium causing oedema
fluid accumulates in alveoli/lungs and causes pulmonary oedema

Question 25

role of hydrostatic pressure

Answer 25

major determinant of fluid movement at capillary level hydrostatic pressure gradient pushes fluid out of blood vessels into interstitium osmotic pressure/oncotic pressure gradient pulls fluid from interstitium into intravascular space

Question 26

left ventricular heart failure

Answer 26

pulmonary oedema - upstream effect drop in renal function - poor perfusion activation of RAAS

Question 27

right ventricular heart failure

Answer 27

less common

Question 28

when does right ventricular heart failure occur?

Answer 28

raised pulmonary vascular resistance

Question 29

what does right ventricular heart failure cause?

Answer 29

back up of pressure from RV - raised JVP/CVP peripheral oedema - ankles hepatomegaly - raised hydrostatic pressure causes liver engorgement

Question 30

what is congestive heart failure?

Answer 30

biventricular heart failure | prolonged left ventricular failure can progress to right sided failure due to increased pulmonary resistance

Question 31

how do patients present?

Answer 31

fluid congestion - wet, none = dry hypoperfusion - cold, well perfused = warm worst prognosis = cold and wet

Question 32

presentation of fluid congestion

Answer 32

raised JVP pulmonary/systemic oedema orthopnoea

Question 33

presentation of hypoperfusion

Answer 33

low BP reduced renal function cold

Question 34

cold

Answer 34

cyanotic and not well-perfused

Question 35

causes of heart failure

Answer 35

``` ischaemic heart failure valvular disease arrhythmias hypertension intra-cardiac shunts drugs cardiomyopathy fluid overload ```

Question 36

how do arrhythmias cause heart failure

Answer 36

reduced CO | poor ejection of atria into ventricles and poor preload

Question 37

how does hypertension cause heart failure?

Answer 37

increased SVR | increased afterload

Question 38

how do drugs cause heart failure?

Answer 38

changes to sympathetic NS | beta blockers can worsen heart failure

Question 39

perfusion of the heart itself

Answer 39

rise in left ventricular wall pressure during systole occludes coronary vessels running through the ventricle therefore most perfusion occurs during diastole

Question 40

perfusion of heart during exercise

Answer 40

during exercise time spent in systole increases and time spent in diastole reduces therefore there is reduced coronary blood flow less effect on right ventricle because there is a lower pressure

Question 41

ischaemic and heart failure

Answer 41

rising wall tension from cardiac failure will worsen coronary flow and myocardial ischaemia tachycardia will worsen coronary flow/myocardial ischaemia even more because will reduce total time spent in diastole

Question 42

mortality after heart failure diagnosis

Answer 42

10% in 30 days 30% in 1 year 50% in 50 years

Question 43

why does heart failure cause increased urination at night?

Answer 43

lying down reduces peripheral oedema so fluid is reabsorbed into vasculature volume intravascularly increases so there is a response to counteract this and increase water loss