Heart failure Flashcards
What is heart failure?
A condition where the heart, due to an abnormality in cardiac function, fails to pump blood at a sufficient rate to meet the requirements of metabolising tissues.
What are the most common cardiac abnormalities which cause heart failure?
Weakened or damaged heart, where the ventricles have stretched and got bigger, preventing the heart from pumping out the needed requirement of blood.
Stiffening of the ventricles, causing them to be unable to fill with enough blood between beats.
What are the most common risk factors for heart failure?
Coronary artery disease and heart attack
Hypertension
Alcohol use
Illegal drug use
Infections
Genetics
How does CAD and MI put you at risk of heart failure?
Fatty build ups in arteries reduce blood flow to the heart which can cause heart attack. Heart attack damages the heart muscle which impairs pumping.
How does hypertension increase the risk of heart failure?
Heart muscles are forced to work harder to pump the blood through the body which can cause it to stiffen or weaken.
Which infections increase the risk of heart failure?
Some viral infections such as COVID, adenovirus, and influenza can cause myocarditis, an inflammation of the heart muscle which can lead to left-sided heart failure.
What are the 2 main classes of heart failure and their symptoms?
Right-sided heart failure - right ventricle affected. Causes fluid to back up into the abdomen, legs, and feet and cause oedema.
Left-sided heart failure – left ventricle affected. Causes fluid to back up into the lungs, causing pulmonary oedema (causes SOB, wheezing).
What are the 2 types of left-sided heart failure?
Heart failure with reduced ejection fraction aka systolic heart failure – left ventricle muscles can’t contract properly, so isn’t strong enough to pump enough blood to the body. The ejection fraction is <40%.
Heart failure with preserved ejection fraction aka diastolic heart failure – left ventricle can’t relax or fill fully.
What should be done to confirm heart failure when suspected?
Measure N-terminal pro-B-type natriuretic peptide (Nt-proBNP)
What is Nt-proBNP?
A hormone secreted by the heart to hekp transport blood through the body.
Why do Nt-proBNP levels help diagnose heart failure?
It is produced by the left ventricle, and when the left ventricle is distended from overworking, as in heart failure, a higher amount is released.
What Nt-proBNP levels indicate chronic heart failure?
<400ng/L - HF unlikely
400-2000ng/L - HF likely. Refer for specialist assessment and transthoracic echocardiography within 6 weeks.
> 2000ng/L - HF very likely. Refer for specialist assessment and transthoracic echocardiography within 2 weeks.
What is a transthoracic echocardiography?
An ultrasound of the heart used to visualise the heart and blood flow. It can be used to determine cardiac abnormalities, assess systolic and dystolic function of the left ventricle, detect intracardiac shunts, and exclude important valve disease.
What factors can influence Nt-proBNP levels?
Increased by ischaemia, tachycvardia, renal dysfunction, elderly, sepsis, COPD, diabetes, and cirrhosis.
Decreased by obesity, African family background, diuretics, ACE inhibitors/ARBs, and beta-blockers.
What is used to measure the severity of heart failure?
NYHA (New York Heart Association) Classification
What are the classes of the NYHA classification?
Class I - no symptoms and no limitations in ordinary activity.
Class II - mild symptoms (mild SOB, angina) and a slight limitation during ordinary physical activity.
Class III - marked limitation in activity due to symptoms, even during less-than-ordinary activity (e.g., walking short distances). Only comfortable at rest.
Class IV - severe limitations and mostly bedbound. Experiences symptoms even at rest.
How should chronic heart failure with reduced ejection fraction be treated?
- ACE inhibitor + beta-blocker
- mineralocorticoid receptor antagonist
- SGLT2 inhibitor/Ivabradine/Digoxin
How should ACE inhibitors be prescribed for CHF?
Start at low dose and titrate upwards every 2 weeks or so until the target dose or the highest tolerated dose is reached.
What monitoring do ACE inhibitors require?
Serum sodium - baseline, 1-2 weeks after starting, and after each dose increment.
Serum potassium - baseline, 1-2 weeks after starting, and after each dose increment.
Renal function - baseline, 1-2 weeks after starting, and after each dose increment.
BP - Serum sodium - baseline and after each dose increment.
General treatment monitoring - once target/maximum tolerated dose achieved, monitor treatment monthly for 3 months and then at least every 6 months.
How should ACE inhibitors be prescribed for HF?
Only start once patient is stable (without fluid overload or hypotension).
Start at a low dose and titrate upwards every 1-2 weeks until target dose or highest tolerated dose is reached.
Why should beta-blockers not be stopped suddenly?
Risk of rebound myocardial ischaemia or infarction, or arrythmias.
Counselling points for beta-blockers in HF?
Symptoms may get worse initially or on increased dose, but they will improve slowly after 3-6 months.
Seek medical advice if symptoms such as tiredness, fatigue, weight gain, or breathlessness worsen.
Do not stop taking them suddenly.
What monitoring do beta-blockers require?
HR, BP, and clinical status, baseline and after each dose increase.
What should be done to HF treatment if HR drops to 50 bpm or less?
Halve dose of beta-blocker, or stop if severe enough.
Review need for other drugs which slow HR.
Arrange for ECG to exclude heart block.
If someone being treated for HF shows signs of clinical worsening, such as increasing dyspnoea, fatigue, oedema, or weight gain, what should be done?
Half dose of beta-blocker.
If increased fluid overload, increase diuretic.
In what conditions are beta-blockers contraindicated?
Asthma or bronchospasm (previous or current)
COPD
Bradycardia/ HR <60bpm
Uncontrolled HF
Hypotension/ systolic BP< 90mmHG
What adverse effects do beta-blockers cause?
Dizziness
Headache
Sexual dysfunction - ED and libido loss
Hypo or hyperglycaemia
Cold extremities and numbness
Bronchospasm
What are some common interactions of beta-blockers?
Hypotension - antipsychotics, tricyclic antidepressanrs, dihydropyridine CCBs, antihypertensives.
Bradycardia - verapamil, dilitiazem, antiarrythmatics, digoxin.
Can beta-blockers be taken during pregnancy?
Avoid bisoprolol and carvedilol - causes reduced placental perfusion which can cause growth retardation, intrauterine death, miscarriage, or early labour. Newborn may experience, hypoglycaemia, bradycardia, respiratory depression, and hypothermia.
How is oedema managed in HF?
Loop diuretics
Name 2 loop diuretics
Furosemide Bumetanide
What monitoring do loop diuretics require?
Renal function, serum electrolytes (K+, Mg2+) - baseline and after 1-2 weeks of initiation or dose increase, or after 5-7 days if >60, CKD, or taking ACEi/ARB/MRA
After treatment is stable, measure renal function and serum electrolytes every 6 months.
Daily weight, fluid intake and output - acute HF
Serum creatinine - baseline, after 1-2 weeks. If increase of more than 20%, re-measure within 2 weeks. If increases 30-50%, ensure prompt review of volume status and reduce dose. If increases 50% or more, assess volume status and respond accordingly.
How should loop diuretics be prescribed for HF?
Start low and increase up
Titrate up or down according to symptoms and signs of fluid overload.
Usually one dose is taken per day, but can be given twice a day for additional diuresis when necessary.
What are some counselling points for loop diuretics?
Look out for signs of hypotension, dizziness, or confusion, which may require a lower dose.
Take dose once a day, but can increase to twice a day if additional diuresis required.
If vomiting or diarrhoea develops, stop diuretic for 1-2 days and maintain fluid intake to avoid dehydration, hypotension, and AKI. If carries on more than 2 days see GP.
May cause hyperglycaemia, low Na+, K+, Ca2+, and Mg2+, increased urination, hypotension, visual disturbances.
What are some common interactions of loop diuretics?
MAOIs - hypotension
Antidiabetics - hypoglycaemia
MTX - reduced renal clearance
Antihypertensives - hypotension
Lithium - increased serum lithium
Antibiotics
NSAIDs -can exacerbate HF.
How do loop diuretics work?
Inhibit the apical sodium/potassium/chloride transporter in the thick ascending limb of the loop of Henle, thus reducing NaCl reabsorption. This leads to a decrease in interstitial hypertonicity and reduces water reabsorption.
Name 3 ARBs
Candesartan
Losartan
Valsartan
Name 2 mineralocorticoid receptor antagonists
Spironolactone
Eplerenone
How do MRAs work?
Diuretics drugs which antagonise aldosterone receptors in the distal tubule of kidney to decrease sodium absorption and increase water excretion.
What monitoring do MRAs require?
Measure serum sodium and potassium and assess renal function before and 1-2 weeks after starting, and after each dose increment,
Measure BP before and after each dose increment.
Once target or maximum tolerated dose achieved, monitor treatment monthly for 3 months and then at least every 6 months.
What are some common side effects of MRAs?
GI discomfort
Dizziness
Confusin
Drowsiness
What is Ivabradine?
A heart-rate-lowering agent that acts by inhibiting the cardiac pacemaker current, a mixed sodium-potassium inward current that controls the spontaneous depolarisation in the sinoatrial node, thus reducing heart rate.
What are some common side effects of Ivabradine?
SOB
Dizziness
Chest pressure
When is Ivabradine used in HF?
If the patient has all of:
o NYHA class II-IV stable chronic heart failure with systolic dysfunction.
o Sinus rhythm with HR of >75bpm
o Left ventricular ejection fraction of <35%
o Can use it in combination with beta-blocker + ACE inhibitor + MRA or if this is contraindicated
What requires monitoring when taking Ivabradine?
Renal function - baseline, annually
LFTs - baseline, annually
Serum potassium - baseline, throughout, and monitor for bradycardia symptoms.
HR - every 6 months.
How should IV furosemide be adminstered for HF?
Should be given in sodium chloride 0.9% NOT glucose 5% as can cause hyperglycaemia
Give 20-50mg IV increased in steps of 20mg every 2 hours, no faster than 4mg/minute, to remove fluid, but endure it isn’t removed too quickly that it causes dehydration.
Use smallest volume possible as already have excess fluid. Comes in vials.
Takes 6 hours to work, so generally give one around 8am and other dose at 4pm, to prevent them having to use toilet regularly at night.
If left untreated, what can HF lead to?
Arrythmias
Blood clots - PE or stroke
Impaired kidney or liver function
Muscle wasting
Respiratory distress
How should acute HF be treated?
On presentation:
IV diuretic therapy, preferably with loop diuretic.
After stabilisation:
Beta-blocker - if already on or if LVSD (ensure stability for 48 hours before discharge)
ACE inhibitor or ARB
Aldosertone antagonist
What indicates acute HF?
BNP > 100ng/L
or
Nt-proBNP >300ng/L
What should be done if acute HF suspected?
- Measure BNP or NT-proBNP
- If raised, perform transthoracic echocardiography, preferably within 48 hours.
