Heart Failure Flashcards
What is heart failure?
Inability of the heart to meet the demands of the body
What can cause heart failure?
IHD
Hypertension
Aortic stenosis
Arrhythmias
How does IHD cause heart failure?
Myocardial dysfunction due to scarring and remodelling
How does hypertension cause heart failure?
Increased afterload on ventricles
Accelerates atherscelerosis
How does aortic stenosis cause heart failure?
Increased afterload on ventricles
What can influence stroke volume?
Pre-load
Myocardial contractility
After-load
What is pre-load
The stretch on the ventricle just before contraction
- volume in ventricle at end of diastole
What is after-load?
Force heart has to contract against
- total peripheral resistance
What is Frank-Starling’s law?
More ventricular distension during diastole = greater volume ejected during systole
Why is CO reduced in heart failure?
Reduced pre-load
- impaired filling
Reduced myocardial contractility
- heart muscle no longer able to produce same force of contraction
Increased after-load
- increased pressure ventricle contracting against
- aortic stenosis or hypertension
What are the 2 main reasons a heart can fail?
Filling problem
- diastolic
Ejection problem
- systolic
How is heart failure classified?
Heart failure with reduced ejection fraction
- systolic dysfunction
Heart failure with preserved ejection fraction
- diastolic dysfunction
How is ejection fraction calculated?
Amount of blood pumped out of ventricle / total amount of blood in ventricle
What is normal ejection fraction?
> /= 50%
What is reduced ejection fraction?
<40%
What is the effect of reduced CO?
Reduces BP
- baroreceptors = increased sympathetic drive
- activation of RAAS
What are the general symptoms of heart failure?
Fatigue
Breathlessness
Leg swelling
Why is there oedema in heart failure?
Heart failure = increased pressure in venous circulation
Higher hydrostatic pressure at venule end of capillary bed
Lower gradient between hydrostatic and oncotic pressure
Less favourable for fluid returning to capillary
What are the symptoms of left sided heart failure?
Fatigue Breathlessness Orthopnoea Paroxymal nocturnal dyspnoea Basal pulmonary crackles Cardiomegaly - displaced apex beat
What are the symptoms of right sided heart failure?
Fatigue
Breathlessness
Peripheral oedema
Raised JVP
What is the NYHA classification of heart failure?
New York heart association
Class 1
- no symptomatic limitation of physical activity
Class 2
- slight limitation of physical activty
- no symptoms at rest
Class 3
- marked limitation of physical activity
- no symptoms at rest
Class 4
- inability to carry out any physical activity without symptoms
- symptoms at rest
What are the blood tests for heart failure?
FBC U+Es Glucose / HbA1c Lipid profile BNP
What is BNP?
Brain natriuretic peptide
Marker of cardiac stress
What may an ECG show?
Axis deviation - cardimegaly
Arrhythmias
