HF Part 1 Flashcards
Definition of HF / CF
An inability of the heart to deliver blood (and O2) at a rate proportionate with the requirements of the metabolising tissues, despite normal or increased cardiac filling pressures
Congestive cardiac failure describes a combination of left and right-sided ventricular failure.
Epidemiology of CF
- M>F
- More prevalent with increasing age
Common: 2-10 (20) %
Costly: 2% of the NHS expenditure in the UK
Disabling: The worst quality of life.
Treatable - not really curable
25-50% of patients die within 5 years of diagnosis
RFs
- Prev MI - greatest RF
- Male, age
- IHD
- HT
- DIabetes
- Renal failure
- AF
Causes of HF
- Myocardial dysfunction - greatest cause
- HT
- Alcohol
- Cardiomyopathy
- valvular
What is HFrEF?
HF with reduced ejection fraction
What is HFpEF?
HF with preserved ejection fraction
Phenotypes of HF
HF due to severe valvular heart disease (HF-VHD)
HF with pulmonary hypertension (HF-PH)
HF due to right ventricular systolic dysfunction (HF- RVSD)
Classes of HF (NYHA)?
Used for assessment of severity of symptoms
Class I: No limitation (Asymptomatic)
Class II: Slight limitation (mild HF)
Class III: Marked limitation (Symptomatically moderate HF)
Class IV: Inability to carry out any physical activity without discomfort (symptomatically severe HF)
What is systolic HF
Inability of the ventricle to contract normally resulting in a
decrease in cardiac output
Systolic HF
- Cardiac output = stroke volume x heart rate
- The ejection fraction is not preserved: an ejection fraction of 40% or less would indicate systolic heart failure.
- The low stroke volume is due to the ventricles not pumping enough blood out.
- HFrEF
Diastolic HF
- Cardiac output = stroke volume x heart rate
- In this case, the stroke volume is low but the ejection fraction is preserved. The reason for the low stroke volume is due to reduced filling of the ventricle (reduced preload)
- HFpEF
Why does right sided HF occur?
- usually occurs as a result of left-sided heart failure.
- Blood starts backing up into the lungs causing pulmonary oedema and congestion
- pulmonary hypertension puts pressure on the right ventricle (cor pulmonale) and causes right-sided heart failure
Causes of systolic failure 1
- Ischaemic heart disease: as less blood and oxygen get to the myocardium, the myocytes start to die
- Hypertension: as arterial pressure increases in the systemic circulation, it gets harder for the left ventricle to pump blood out into that hypertensive systemic circulation.
Causes of Systolic failure 2
- Left ventricular hypertrophy: increased muscle mass requires increased oxygen supply - making it more likely for that the muscle will die
- Dilated cardiomyopathy: heart chambers dilate and thin out, leading to weaker contractions.
Causes of diastolic failure
- Left ventricular hypertrophy: causes the ventricular chamber to decrease in size which means less blood can enter.
- Restrictive cardiomyopathy: ventricle can’t stretch enough to accommodate the blood
- Valvular disease: e.g. aortic stenosis causes LVH or mitral regurgitation means blood doesn’t enter the ventricles in the right amount as it leaks back into atria
- Arrhythmias e.g. atrial fibrillation
