Heart failure Flashcards
define Heart failure (HF)
abnormality in cardiac structure/function leading to failure of heart to pump oxygen at a fast enough rate to meet needs of metabolizing tissues
what are the diff types of HF
1) HFref - reduced ejection fraction
- enlarged, weakened ventricles, pump out less blood than usual
- systolic (pumping) dysfunction
- reduced muscle contraction, contraction is less efficient
2) HFpej - preserved ejection fraction
- stiff ventricles are filled with less blood than usual
- diastolic (filling) dysfunction
how do neuro hormonal systems work due to reduced CO?
RAAS - renin released by kidneys in response to low blood vol
- angiotensin II causes peripheral vasoconstriction
- aldosterone causes Na retention
baroreceptors detect decrease in arterial pressure - Increase sympathetic activity
- angiotensin II causes noradrenaline and adrenaline release
- increase heart rate + force of contraction
what is HF a result of?
1) comprised contractility - decreases stroke volume + cardiac output (CO)
2) enlarged + inefficient cardiac muscles (particularly left ventricle) - cardiac dilation/hypertrophy - increases cardiac workload + O2 consumption
3) decreased ejection fraction (EF) in left ventricular dysfunction (LVD) or left sided HF - leads to decreased CO (most cases of HF due to LVD)
4) right sided HF - less common- indicated by increased jugular venous pressure (JVP) - classic sign of venous hypertension
how are the kidneys & liver affected in HF
renal dysfunction - as kidneys require 20% of CO - when reduced - affects function
hepatomegaly (enlarged liver) - as large amounts of fluid are retained in HF
epidemiology and statistics of HF
about 1-2% affected in UK
HF has poor prognosis - worse than breast/prostate cancer
30-40% die within a year of diagnosis
10% mortality rate thereafter
what are the common causes of HF
hypertension
coronary artery disease
ischemic heart diseases - STEMI, acute coronary syndrome, stable angina
arrhythmias
alcohol induced
infection (myocarditis)
congenital heart disease
what is the diagnosis for HF
common symptoms:
Shortness of breath (SOB)
SOB when lying flat
fatigue
oedema - peripheral and widespread
clinical signs:
respiratory crackles - from fluid build up in lungs
hepatomegaly
renal dysfunction
rapid weight gain
raised JVP
reduced exercise tolerance
diagnostic tools - echocardiograms, ECG, chest x-ray, NT-proBNP (natriuretic peptide elevated)
importance of NT-pro-BNP
N-terminal pro B type natriuretic peptide - is an inactive peptide released along with active peptide BNP when heart walls are stretched or if there is a pressure overload e.g. fluid overload
BNP acts by causing fluid + sodium loss in urine
therefore in HF - where heart walls are stretched - BNP is released, NT-pro-BNP is released in same amount but is much more stable - hence good marker for BNP level
if NT-pro-BNP < 400 ng/L - HF is not confirmed
if >400 ng/L - refer urgently
non pharmacological management/lifestyle advice for HF
smoking cessation
reduced alcohol intake
reduced saturated fats/salt
healthy diet
reduced fluid intake
annual flu vaccine
cardiac rehab
pharmacological management of HF with reduced EF - NICE pathway
1) ACEi + BB
2) consider ARB if patient is intolerant to ACEi
3) consider hydralazine + nitrate if intolerant to ACEi & ARB
4) consider aldosterone antagonist or ARB or hydralazine + nitrate
5) digoxin
6) implantable devices
7) revascularisation + transplantation
what are the important points about ACEi?
ramipril - most extensive cardioprotective data
titrate dose up - usual starting dose is 2.5mg max being 20mg
drastic hypotension can occur so don’t use ACEI with high dose loop diuretic (e.g. 80mg furosemide) - if you take off furosemide chance that patient may get rebound pulmonary oedema, so use lower dose
in renal dysfunction - risk of hyperkalemia so switch to hydralazine+nitrate - better at improving exercise tolerance
ACEi induced dry cough and c/i in angiodema - ARB has less chance of these side effects
important points for beta blockers
bisoprolol - highly cardioselective, beta-1 selective adrenoreceptor blocker , initially 1.25mg increase weekly to 5mg and 4 weekly to 10mg
carvedilol - non beta selective, alpha-1 selective blocker reduces peripheral vascular resistance
nebivolol - beta-1 selective adrenoreceptor blocker
avoid in those with asthma - due to bronchospasm
imp points for aldosterone antagonist
spironolactone - aldosterone antagonist of choice
K+ sparing diuretic - use with caution in conjunction with ACEi - risk of hyperkalemia - monitor K+ levels
imp points for digoxin & ivabradine
digoxin - if patient has AF and still symptomatic after 1st and 2nd line treatment
ivabradine - if patient is tachycardic and still symptomatic after 1st/2nd line
