Heart failure Flashcards
What is heart failure?
any structural or functional disorder that impairs the ability of the heart to function as a pump to support a physiological circulation
This can be due to an inability for the heart to fill will blood correctly (diastolic) , or an inability of the heart to eject blood effectively (systolic)
What is the incidence of heart failure in the UK per 1000?
2 in 1000
What is preload?
the amount of sarcomere stretch experienced by cardiomyocytes at the end of ventricular filling during diastole
Describe how increasing preload reduces cardiac function in heart failure:
1) in heart failure, less blood is ejected from the heart. The remaining blood increases diastolic volume which stretches cardiomyocytes
2) too much preload leads to a depression in ventricular function and stroke volume
What is left sided heart failure?
Inability of left ventricle to pump adequate amount of blood
Describe how heart failure can lead to oedema:
as ejection fraction falls, diastolic volume increases
this creates a backpressure that increases venous pressure allowing fluid to pool in the interstitium
What is outflow resistance?
the resistance against which the ventricle contracts
Give 3 factors that determine outflow resistance:
- Pulmonary and systemic resistance
- Physical properties of the vessel wall
- Volume of the blood ejected
What does Inotropy refer to?
force of contraction
Describe how heart failure affects salt and water levels in the body:
The increased venous pressure leads to salt and water retention while the reduced cardiac output reduces the systemic blood pressure, activating the RAAS system, also enhancing salt and water retention
Give 3 ways in which the myocardium remodels in heart failure:
- Hypertrophy
- Loss of myocytes
- increased interstitial fibrosis
Describe how endothelial function changes in HF:
endothelial responsiveness to nitric oxide reduces, reducing vasodilatory properties
What is systolic heart failure?
where ventricles cannot contract properly
What is the ejection fraction threshold for systolic heart failure?
less than 40%
What is diastolic heart failure?
where ventricles cannot relax and fill normally causing increased filling pressures
What is another name for diastolic heart failure?
heart failure with preserved ejection fraction
Give 6 common causes of heart failure:
1) ischaemic heart disease (35-40%)
2) cardiomyopathies (30-34%)
3) hypertension (15-20%)
4) valvular disease
5) kidney disease
6) IV fluids in frail, elderly patients
How does hypertension cause heart failure?
it increases pressure against which the left ventricle is pumping against, reducing ejection fraction and thus increasing pre-load
How do valvular diseases cause heart failure?
regurgitation leaves more blood in the left ventricle, decreasing the ejection fraction and thus increasing preload
Give 2 ways in which kidney disease can cause heart failure:
1) electrolyte imbalances can cause arrhythmias
2) poor kidney function increases circulating volume and hence vascular resistance
Give 8 risk factors for heart failure:
1) male sex
2) obesity
3) old age
4) dyslipidaemia
5) alcohol abuse
6) diabetes
7) sleep apnoea
8) smoking
Give 4 key symptoms of heart failure:
1) exertional dyspnoea (often secondary to pulmonary oedema)
2) orthopnoea (breathlessness laying flat)
3) paroxysmal nocturnal dyspnoea ( an attack of severe shortness of breath and coughing that generally occurs at night.)
4) fatigue
Give 8 signs associated with heart failure:
1) tachycardia
2) increased JVP
3) cardiomegaly
4) third and fourth heart sounds
5) bi-basal lung crackles (from oedema)
6) pleural effusion
7) peripheral ankle oedema
8) ascites
What is congestive heart failure?
failure of both right and left ventricles, which is common
What is low-output HF?
heart failure resulting from reduced cardiac output [most common type] – also referred to as HFrEF – Heart Failure reduced Ejection Fractions
What is high output HF?
heart failure that occurs in normal or high cardiac output due to metabolic demand and supply mismatch, either due to reduced blood oxygen carrying capacity [anaemia] or increase body metabolic demand [thyrotoxicosis] – also referred to as HFpEF – Heart Failure preserved Ejection Fraction
How does ischaemic heart diease cause heart failure?
Causes impaired ventricular function, therefore reduced contractility function and hf
What is mean arterial pressure?
Cardiac output x total peripheral resistance
What is the pathophysiology of heart failure?
- Heart failure causes a drop in mean arterial pressure that initially stimulates baroreceptors that feed back onto the medullary cardiovascular centre.
- MCVC tries to increase and maintain the mean arterial pressure by reducing the vagal tone and increase sympathetic tone, leading to increase heart contractility and rate therefore output.
- The sympathetic system also stimulates the contraction of arteries (increasing total peripheral resistance) and veins (increasing venous return) and the release of adrenaline from the adrenal medulla, which stimulate all of the above actions.
- the RAAS system is also stimulated in HF due to reduced kidney perfusion caused by reduced MAP, vasoconstriction and direct sympathetic stimulation.
- The RAAS system releases aldosterone and ADH causing sodium and water retention.
- These mechanisms are beneficial initially as they increase blood volume, therefore venous return, stroke volume and heart rate therefore maintaining a high cardiac output however eventually worsening the situation.
How does a increased total peripheral resistance worsen HF?
Increase afterload therefore increasing workload and strain on the heart
Tissue underperfusion leading to ischemia
RAS system stimulation
How does increased HR worsen HF?
Increase workload and therefore oxygen demand of the heart
How does fluid retention worsen HF?
- Increase stretching of the heart eventually leading to dilatation of ventricles which possess reduced contractility
- Fluid build up causes fluid transudation into interstitial tissue causing peripheral and pulmonary oedema
- Hyponatremia and hypokalemia
What is pink frothy sputum indicative of?
pulmonary oedema
What are 3 signs of fluid overload?
Peripheral oedema – ankles +/- sacrum
Ascites
Elevated JVP [venous congestion]
Give 4 CXR signs associated with heart failure:
1) cardiomegaly
2) pulmonary congestion
3) pulmonary oedema
4) Kerly B lines
What are Kerly B lines?
Horizontal lines in the bases of the lung fields indicative of fluid in the interlobular septa
Give 4 types of investigation used to diagnose heart failure:
1) CXR
2) ECG
3) echocardiography
4) bloods
What is an echocardiogram used to assess in heart failure investigations? (4)
1) chamber dimension
2) ejection fraction (systolic and diastolic function)
3) wall abnormalities
4) cardiomyopathies
Where and when is atrial natriuretic peptide produced?
atrial myocytes in response to stretch
What is the effect of ANP? (3)
1) induces diuresis
2) induces natriuresis
3) suppresses RAAS system
(overall reducing blood pressure)
What is natriuresis?
excretion of sodium in the urine
Where and when is B-type natriuretic peptide produced?
ventricles in response to wall stress
What condition are elevated levels of circulating ANP associated with?
congestive heart failure
What is the effect of BNP? (2)
1) relaxing smooth muscle in blood vessels
2) enhancing diuresis
(overall reducing blood pressure)
where is C-type natriuretic peptide secreted from?
CNS and endothelium
Describe the steps in managing acute/ sudden deterioration heart failure (hint: Pour SOD):
1) ‘Pour away’ (stop) their IV fluids
2) sit the patient upright
3) give oxygen
3) diuretics
Give 4 factors that need to be monitored in order to establish a patient’s fluid balance:
1) fluid intake
2) urine output
3) U+Es
4) daily body weight
Name the 5 groups of key heart failure drugs used in chronic management:
1) ACE inhibitors
2) beta blockers
3) diuretics
4) angiotensin II receptor antagonists (ARBs)
5) aldosterone antagonists
Give 4 side effects of ACE inhibitors:
1) cough
2) hyperkalaemia
3) renal dysfunction
4) hypotension
How do loop diuretics work?
they act by promoting the renal excretion of salt and water by blocking tubular reabsorption of Na+ and Cl-
Give two examples of loop diuretics:
1) furosemide
2) bumetanide
Give an example of a thiazide diuretic:
Bendroflumethiazide
Give 3 examples of ARBs?
1) candesartan
2) losartan
3) valsartan
When are ARBs used to manage chronic heart failure?
when ACE inhibitors are contraindicated
Give an example of an aldosterone antagonist:
Spironolactone
Give an example of an inotrope drug:
noradrenalin
When would a patient be given inotropes for heart failure?
in severe cases
What is an inotrope?
An inotrope is a type of medicine that affects the contraction of the heart muscle. Positive inotropes stimulate and increase the force of contraction, while negative inotropes weaken the force of muscular contractions, decreasing the heart’s workload
What drugs will most patients be treated with?
ACEi and diuretic
If a patient is intolerant to ACEi and ARBs what might be considered?
Hydralazine + Nitrates
Who should beta blockers be avoided?
Patients with fluid overload
Advice is to treat the fluid overload first and then start beta-blocker once euvolaemic
What are 4 contradictions for beta blockers?
Asthma
2nd or 3rd degree heart block
Sick sinus syndrome
Sinus bradycardia (<50bpm)
What is the difference between thiazide and loop diuretics?
thiazide causes a more gentle and slower onset diuresis, often used first line in milder forms of heart failure
When is digoxin considered as treatment?
Sinus rhythm patients that remain symptomatic even after other pharmacological interventions (third line after ACE-i and diuretics)
Patients with severely impaired left ventricular function
Recurrent hospital admissions
Treating AF in CHF
Amiodarone in arrhythmic patients
WHAT IS THE OFFICAL STEP-WISE APPROACH FOR TREATMENT OF HEART FAILURE?
ACE inhibitors or ARB
ADD diuretic
ADD beta-blocker (once euvolaemia)
ADD aldosterone antagonist (spironolactone or amiloride)
then – increase all above to maximum tolerated doses
CONSIDER ARNI (and cease ACE-i) for patients who remain with an EF <40%
CONSIDER ivabridine
CONSIDER another vasodilator, e.g. isosorbide dinitrate or hydralazine
CONSIDER digoxin
CONSIDER implantable cardiac devices
What causes right sided heart failure most commonly?
Left sided heart failure
What does right sided heart failure lead to?
- Systemic venous congestion therefore peripheral oedema and hepatic congestion and tenderness
Right ventricular failure is often caused by pulmonary hypertension secondary to chronic lung disease such as: (4)
1) COPD
2) pulmonary fibrosis
3) bronchiectasis
4) recurrent pulmonary emboli
Give 3 heart failure symptoms that are associated more so with right ventricular failure:
- Peripheral oedema
- Hepatomegaly
- Raised JVP
What is commonly found on the history and exam of left sided heart failure?
Fatigue
Poor exercise tolerance
Syncope (sudden drop in blood pressure and heart rate)
Systemic hypotension
Cold peripheries
Slow capillary refill
Peripheral cyanosis
Weight loss
Nocturia
Pulsus alternans
Mitral regurgitation
S3/S4 gallop (left-sided)
What is commonly found on the history and exam of right sided heart failure?
Left failure symptoms if decreased RV output leads to LV underfilling
Nausea
Anorexia
Facial engorgement
Epistaxis (nose bleed)
Tricuspid regurgitation
S3/S4 gallop(right-sided)
What are pulsus alternans:
arterial pulse waveform showing alternating strong and weak beats.
➢Almost always LV systolic impairment
➢Carries a poor prognosis
What is Kussmaul’s sign?
A paradoxical rise in JVP on inspiration or a failure in the appropriate fall of the JVP with inspiration
What is alveolar oedema?
‘Bat wing’ shadowing on CXR
feature of left sided heart failure
What is congestive heart failure?
when the heart muscle is overworked due to stress, high blood pressure, arteriosclerosis, and fluids begin to collect in the body tissues
Give 8 conditions that cause congestive heart failure:
1) coronary artery disease and MIs
2) restrictive cardiomyopathies
3) hypertension
4) constrictive pericarditis
5) arrhythmias
6) congenital defects
7) valvular defects
8) heart block
