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.