Heart Failure Flashcards
What is heart failure
Inability of the heart to meet the demands of the body
A clinical syndrome of reduced cardiac output, tissue hypoperfusion, increased pulmonary pressure and tissue congestion
What allows to heart to work as an effective pump
Functioning muscle
Correct chamber size
One-way valves
Name some conditions that cause heart failure (aetiology of HF)
IHD/coronary heart disease - myocardial dysfunction
Hypertension - increase afterload
Aortic stenosis - increase afterload
Other valvular or myocardial structural diseases
Cardiomyopathies
Arrhythmias
Pericardial diseases
How do we measure the volume pumped out of the ventricle per minute
CO = SV x HR
What factors influence stroke volume and are they positive or negative influences
Pre-load - positive
Myocardial contracility - positive
After-load - negative
What causes the stroke volume to be reduced
Reduced pre-load - impaired filling during diastole
Reduced myocardial contractility
Increased afterload - this usually affects pre-load and/or myocardial contractility
What are the two main types of problems and which part of the heart cycle do they affect
Filling problem - diastole
Contractility/ejection problem - systole
What are the two main classifications of heart failure
HFrEF - heart failure with reduced ejection fraction, systolic dysfunction
HFpEF - heart failure with preserved ejection fraction, diastolic dysfunction
What is the ejection fraction and how is it measured
It is amount of blood pumped out of the ventricle divided by total amount of blood in ventricle
Measured on echocardiogram
When is an ejection fraction said to be reduced
When it is <40%
Why are heart failures cuased by a filling problem said to be preserved
Ventricle ejects less volume but there is is less volume to begin with, so the fraction of what is available to eject is still >50% so the ejection fraction is preserved
What is cor pulmonale
Isolated RV heart failure secondary to chronic lung disease
What is the term for when a patient has isolated RV heart failure secondary to chronic lung disease
Cor pulmonale
What physiological mechanisms are activated by the drop in cardiac output and what activates them
Increased sympathetic drive activated by baroreceptors
Activation of the RAAS pathway by decreased renal perfusion
What overall effect does the activation of the compensatory mechanisms have on the heart
Increased sympathetic drive increases afterload
Activation of the RAAS pathway increases preload and afterload
Both of these systems increase the cardiac work, overworking the heart further
What are the clinical signs and symptoms of heart failure
Fatigue/lethargy
Breathlessness
With or without leg swelling - both legs affected!
Pitting oedema in peripheral tissues
Pulmonary Oedema
What are the symptoms of LV heart failure
Fatigue/lethargy
Breathlessness - exertional
Orthopnoea
Paroxysmal nocturnal dysnoea
Basal pulmonary crackles
Cardiomegaly - displaced apex beat
What are the symptoms of RV heart failure
Fatigue/lethargy
Breathlessness
Peripheral pitting oedema
Raised jugular venous pressure
Tender, smooth enlarged liver
What investigations and examinations are done to test for heart failure
FBC - anaemia can cause symptoms of heart failure
Electrolytes and renal function - chronic kidney failure can cause fluid overload and HF symptoms
Glucose/HbA1c
Lipid profile
BNP - elevated BNP suggests heart failure, normal BNP with breathlessness usually excludes HF
ECG - abnormal ECG and elevated BNP suggests HF
Chest X-ray - pulmonary oedema
Echocardiogram - measure EDV
What is the treatment of acute heart failure
Oxygen - CPAP
Intravenous loop diuretics - furosemide
Herapin to prevent DVT
Possibly need IV nitrates to reduce preload with/without coronary vasodilation
How do you manage heart failure long term
Correct underlying cause - intervention, implantable device
Non-pharmacological measures (lifestyle changes)
Pharmacological therapy - symptomatic improvement, delay progression of HF, reduce mortality. E.g. ARBs, ACEi, beta-blocker, spironolactone
Treat complications/associated conditions/cardiovascular risk factors
Which two neuro-hormonal systems are targeted in drug therapy of HF
SNS
RAAS
What are the compensatory mechanisms done by the SNS
Increase cardiac contractility
Arterial and venous vasoconstriction
Tachycardia
What are the deleterious effects of the SNS being stimulated long term
Beta-adrenergic receptors are downregulated
Noradrenaline induces cardiac hypertrophy/myocyte apoptosis and necrosis via alpha-receptors
NA induces upregulation of RAAS
Reduced heart rate variability
How do beta-blockers work
Reduce heart rate
Reduce BP
Reduced BP and HR reduces myocardial oxygen demand
Reduce mobilisation of glycogen
Negate unwanted effects of catecholamines
How should beta-blockers be given to a patient
Administered once patient is stable
Start at a low dose and titrate slowly, increasing dose
What do you use to treat the RAAS
ACE inhibitors
Angiotensin receptor blockers
What might management of HF include
Pharmacological - ACE, B-blockers, spironolactone
Intervention - treat underlying disease, heart transplant, mechanical assist devices
Implantable pacemakers - biventricular pacing
Implantable defibrillators
Lifestyle modifications - Reduce salt, alcohol and BP, increase aerobic exercise
