heart failure Flashcards
What is heart failure
- Results from structural and/or functional cardiac disorders - usually of gradual onset
Unable to sustain adequate blood delivery around the body
HF epidemiology
0.3-2% population
50% dead at 5 years
10% AF associated
aetiology of HF
pump failure - damage has lead to a decrease in contractility (IHD)
overloading - extra workload causes decreased contraction force and delayed relaxation
what can cause pump failure in the heart
MI
cardiomyopathy
arrythmias
inflammation
infection
what can cause the heart to be overloaded
excessive afterload - high systemic/pulmonary, vascular resistance, valve dysfunction
excessive preload - fluid retention
what are some other less common causes of HF
arrythmias
pregnancy
obesity
what is acute HF
usually after MI
- cardiac output drops - decompensated
- contractility drops - compensated
what is chronic HF
same as acute, but slower onset, pt can remain in compensated HF indefinitely
3 clinical features of HF
exercise limitation and fatigue - less blood flow to muscles
SOB - back pressure from heart causes fluid accumulation on lungs
oedema - salt/water retention
what are the main causes of symptoms of HF
hypoperfusion and oedema
what is hypoperfusion
Impaired flow ahead of heart/chamber affected
what does hypoperfusion cause
peripheral vasoconstriction
fatigue
cold extremities
fluid retention
tachycardia/tachypnoea
what is oedema inHF
increase in pressure in veins draining to the heart
what does right sided oedema cause
peripheral oedema
liver enlargement
raised jugular pressure
fluid retention
what does left sided oedema cause
pulmonary oedema
SOB
cough/wheeze
how is HF diagnosed
swelling, jugular pressure, lung sounds
natriuretic peptides
ejection fraction
xray/ecg/bp
what is HFrEF
HF with reduced ejection fraction - drugs!! (<40%)
what is HFpEF
HF with preserved ejection fraction (>50%)
what is HFmrEF
HF with mid range ejection fraction (41-50%)
how do you treat HF caused by myocardium disease
increasing inotropy
how do you treat HF caused by excessive load
reduce pre/after load
what is 1st line treatment for HFrEF and what are they used for
loop diuretic - furosemide - decreased preload and oedema
ACEi - ramipril - reduce pre/after load
B blockers - bisoprolol - reduce pre/after load
aldosterone antagonists - spironolactone- reduce pre/after load and LVH risk
which medicines can be added on to control HF
digoxin - myocardial stimulation
isosorbide dinitrate - preload
hydralazine - afterload
ARNI - pre/after load
SGLT2 - pre/after load
which 3 types of diuretic can be used in HF
thiazide - bendro 5mg max for mild HF
loop- mainstay
metolazone - atypical for resistant AF (2.5-5mg stat or every 2-3 days)
what are ARNIs and how do they work
angiotensin receptor neprilysin inhibitors - valsartan ARB and sacubitril neprilysin inhibitor - stops degradation of natriuretic peptide
ESC 1st line for HF guidelines
ACEi/ARNI
B blocker
MRA (spironolactone)
SGLT2
loop diuretic
what is starlings law of the heart
The greater the volume of blood entering the heart at diastole, the greater the volume of blood ejected during systolic contraction
what are the 4 mechanisms of compensation in HF
cardiac enlargement
arterial constriction
increased sympathetic drive
salt/water retention
how does cardiac enlargement work in HF compensation
- Cardiac muscle is stretched from increased residual volume after contraction - impairment as a pump - Left ventricular hypertrophy (LVH) - enlargement and thickening of left ventricular wall
how does arterial constriction work in HF compensation
- Arteries constrict when blood output is reduced to direct blood to essential organs
how does increased sympathetic drive work in HF compensation
Reduced tissue perfusion activates sympathetic nervous system via baroreceptors, Exposes heart to catecholamines with positive inotropic and chronotropic effects - increase force and rate of contraction (noradrenaline, angiotensin, aldosterone)
how does salt/water retention work in HF compensation
reduced cardiac output = decreased renal perfusion
renin release, aldosterone I and II produced = aldosterone increased - increases pre-load via water retention at renal tubule
- atrial natriuretic peptide release
what symptoms are associated with class I of the new York heart associations classification of HF symptoms
no limitations
what symptoms are associated with class II of the new York heart associations classification of HF symptoms
slight limitation
comfortable at rest
ordinary activity = fatigue, palpitation, angina
what symptoms are associated with class III of the new York heart associations classification of HF symptoms
marked limitation on activity
still comfortable at rest
less than ordinary activity = symptoms
what symptoms are associated with class IV of the new York heart associations classification of HF symptoms
inability to do anything without discomfort
symptoms still present even at rest
