Lecture 8 - HF Flashcards
What is HF?
Complex clinical syndrome of symptoms and signs suggest the heart’s efficiency as a pump is impaired.
Caused by structural or functional abnormalities 0f the heart
Describe the causes of HF
The inability of myocytes to contract normally causes reduced cardiac output
Neuro-hormonal feedback further stresses already struggling CV system
Coronary Heart Disease
Ischaemic Heart Disease - most common
Cardiomyopathy
Hypertension
Undilated cardiomyopathy (amyloidosis, sarcoidosis)
Valvular heart disease (mitral, aortic, tricuspid valves) - stenosis (narrow aortic valves) - more common in older patients and or regurgitation - leaky valves
Drugs/ toxins (alcohol, cocaine, cytotoxic agents)
Arrhythmias (AF, bradycardia)
Obesity
HIV infection
What cardiac structural and functional abnormalities in obesity are seen?
Enlarged heart - heart walls increased
Fat around the heart
Describe the importance of vascular remodelling post MI
Important to revascularize patients in MI quickly
Heart loses its tension and the walls become very thin
Hypertrophy - hear tries to correct fault elsewhere - leads to significant problems long term and progresses into heart failure
Define ejection fraction
The percentage of blood from the left ventricle that is pumped out in each beat
Describe the clinical syndromes of heart failure
Left ventricular systolic dysfunction (LVSD) - heart failure with reduced ejection fraction - caused by IHD, valve disease, arrhythmias and hypertension
Diastolic heart failure - heart failure with preserved ejection fraction (HF-PEF)
=> Increased stiffness in the ventricular wall, increased left ventricular wall thickness
=> Diastolic filing impaired - treat with diuretics
=> Common in elderly hypertensives, diabetics mellitus, sedentary lifestyle
=> Can occur with primary cardiomuyopathies
Right ventricular systolic dysfunction (RVSD) - secondary to LVSD
Clinical symptoms of heart failure
Fatigue, exertional dyspnoea, decreased exercise tolerance SOB, orthopnoea (lying down) , paraoxysmal nocturnal dyspnoea (suddenly SOB at night), bendopnea (bends down SOB)
Clinical signs of heart failure
Tachycardia
Cardiomegaly
Fluid retention (oedema) - particularly in lungs and legs and feet
Elevated venous pressure (JVP)
Abnormal heart sounds (due to structural changes/ cardiomegaly) - e.g. enlarged heart
Name the NYHA classification of HF
Class 1 - no limitations on physical activity
Class 2 - slight limitation, comfort on rest but ordinary physical activity causes symptoms
Class 3 - marked limitation of activity, comfort at rest but less than ordinary activity causes symptoms
Class 4 - unable to carry out any physical activity without discomfort, symptoms at rest
Explain percentages of ejection fraction
50-70% normal
40-49% borderline
<40% reduced
<30% severe dysfunction
What does an echocardiogram measure?
Ejection fraction
Size of chambers particularly LV
Presence of regions wall abnormalities
Describe the Atrial Natriuretic Peptide (ANP)
Released from partial myocytes in response to stretch
- induces diuresis, natriuresis, vasodilation, suppresses renin-angiotensin system
- levels raised in HF
Describe the Brain Natriuretic Peptide (BNP)
Released by ventricles in response to myocardial wall stress
- N-terminal (NT) - pro BNP is cleaved from proBNP to release BNP
- Increased BNP and Increased NT-proBNP in heart failure
Name the natriuretic peptides
Atrial Natriuretic Peptide (ANP)
Brain Natriuretic Peptide (BNP)
C-type peptide has similar affects to ANP and BNP
the higher the levels - the more they need to be investigated
Describe disease progression
Hospitalisation of HF
Survival rates worsen with age
Survival most limited in amyloid, HIV, anthracycline chemotherapy and hemochromatosis induced cardiomyopathy
Progressive pump failure
Sudden cardiac death due arrhythmias
Harder to cope with other co-morbidities
