u12w4: heart failure Flashcards
What are the key features of left-sided heart failure?
Dyspnea - SOB
Orthopnoea - dyspnoea on lying down
Paroxysmal noturnal dyspnea -
Pulmonary congestion and odema = basal crackles
Exercise intolerance
What are the key features of right sides heart failure?
Odematous swelling of feet, ankles, legs
Hepatomegaly - enlarged, palpable, tender liver (nutmeg appearance on gross and microscopic examination)
Ascities
Escessive nocturnal urination (when body absorbed excess fluid and converts into urine)
Raised jugular venous pressure
Exercise intolerance.
What is the kep epidemiology of heart failure?
Annual incidence of 10% in over 65yrs
The long term outcome is poor and approximately 50% of patients are dead within 5 years.
What are the three main causes of heart failure?
- Ishcemic heart disease (35-40%)
- Cardiomyopathy-dilated (30-34%)
- HTN (12-20%)
What are some less common causes of heart failure?
1.Cardiomyopathy-hypertrophic (disatolic dysfunction) or restrictive (stiff-non compliant ventricles)
2. valve disease
3. Congenital (ASD, VSD)
4. Alcohol and chemo (imatinib)
5. Hyperdynamic circulation (anaemia, thyrotoxicosis, Pagets disease)
6. RtHF - from RV infarct, pulmonary hypertension, COPD
7. Severe brady/tachycardia (AF, CHB, SSS)
8. Pericardial disease (constrictive pericarditis)
9. Infections (myocarditis)
What blood tests are ordered to investigate someone with heart failure as a differential diagnosis?
FBC - rule out anemia
Creatinine and electrolytes - kidney damage as cause of fluid retention
LFTs - nutmeg liver, liver congestion
Troponini - I most specific for MI
BNP - ventricular strain
Thyroid function - cause of heart failure
What investigations should be ordered for a patient with heart failure as a differential?
Blood tests
Chest XR
ECG
Echo and stress echo
Nuclear cardiology
MRI
Coronary catherisation
Biopsy
Cardiopulmonary testing
Ambulatory 24-hour ECG monitoring
How are the heart sounds altered in heart failure?
Third and fourth heart sounds may appear
THird heart sound - rapid passive ventricular filling during diastole, can indicate a distened ventricle (Dilated cardiomyopathy)
Fourth heart sound - occurs in late diastole, resistance to ventricular filling, active ventricular filling, indicates a stiffned ventricle.
What are the different sings of heart failure?
Tachycardia
Elevated JVP
Cardiomegaly
Third and fourth heart sounds
Bi-basal crackles
Pleural effusion
Peripheral ankle oedema
Ascites
Tender hepatomegaly.
What is the simple pathophysiology of heart failure?
Heart fails - decreased cardiac output
Compensatory mechanisms (RAAS and SNS) attempt to maintain cardiac output and peripheral perfusion - affects venous, return, outflow resistance, contractility of myocardium and salt/water retention.
Mechanisms are overwhelmed no longer beneficial- tend to increase preload and afterload increasing cardiac work and causing myocyte damage.
In particular adrenergic stimulation a) incr contractility/HR in cardiac work
b) direct cardiotoxicity through myocyte damage.
Increase energy consumption
Structural remodelling of the heart
What are some of the pathophysiological changes seen in heart failure?
Ventricular dilation
Myocyte hypertrophy
Increased collagen synthesis
Altered myosin gene expression
Altered sarcoplasmic Ca2+ ATP density
Increased atrial natiuretic peptide secretion
Salt and water retention
Sympathetic stimulation
Peripheral vasoconstriction
What is myocardial remodelling in heart failure?
Process of progressive alteration of ventricular size, shape and function due to mechanical, neurohormonal and genetic factors.
What ventricular remodelling occurs after MI leading to heart failure?
Initial infarct
The infarct will expand over hours to days - this region of tissue has died so becomes thinner and stretched.
Wall stress increases - leading to progressive dilation of the infarcted area
Other areas in the wall may become hypertrophied due to increased wall stress.
Fibrosis develops in areas of remodelling - not enough oxygen and nutrients so cardiac myocytes die.
Over days to months the global remodelling occurs and the heart function is lost.
What ventricular remodelling occurs in systolic and diastolic heart failure?
Normal heart - undergoes uneccessary strain e,g tachycardia from arrhythmia or increased afterload.
Leads to hypertrophied heart due to increased workload - diastolic heart failure
This and other methods are poor compensation to increase CO leads to Insufficient oxygen delivered to tissue to reach demand, this causes death of tissue resulting in a dilated heart with fibrosis - systolic heart failure.
THis is progressive ventricular hypertrophy and dilation - does not require infarction.
What is the New York Heart Association classification of symptoms severity in heart failure?
Class 1 - no limit of physical activity, ordinary PA does not cause fatigue, palpitation, dsypnea (aka can play baseball, jogging)
Class 2 - slight limitation in pa, comfortable ar rest, but ordinary activity causes f,p,d. (walk and gardening)
Class 3 - marked limitation of physical activity, comfortable at rest, less than ordinary pa cause f,o,d. (can shower and get dressed)
Class 4 - unable to do pa, symptoms of heart failure at rest, discomfort worsens in pa. (no activity without discomfort)
Orindary activity - walking or climbing staris
Less than ordinary - yoga, gentle stretching
What criteria are required to be diagnosed with HF-REF?
- Symptoms typical of heart failure
- Signs typical of heart failure
- Reduced LV ejection fraction
What criteria are required to diagnose of HF-PEF?
Symptoms typical of heart failure
Signs typical of heart failure
Normal or only mildly reduced LV ejection fraction and LV not dilated
Relevant structural heart disease (LV hypertrophy/left atrial enlargement or diastolic dysfunction)
What is the relationship between diastolic and systolic heart failure and ejection fraction?
Systolic - reduced ejction fraction, loss of contractility - tends to be dialted ventricle due to thinning and weakening of wall
DIastolic - ejection fraction remains, volume of filling decreases, cardiac hypertrophy (e.g from hypertension), reduces filling but contractility remains the same.
What are the three parameters used to describe the function of the ventricles?
- Stroke volume - the volume of blood ejected by the ventricle in one beat
- Ejection fraction - the fraction of the EDV ejected in one stroke volume
- Cardiac output - the total volume ejected by the ventricle per unit of time.
This all influences EDV which correlates with venous return.
What factors affect stroke volume?
Preload - intrinsic to the heart, affects the resting ventricular muscle fibre length hence the force generated by contraction.
Contractility - ionotropic effect, extrinsic to the heart, does not affect reting muscle fibre length
Afterload - changes aortic pressure, external to the heart, changes the amount of pressure the ventricles must generate before the aortic valve will open.
How do you calculate ejection fraction?
What is it an indicator of?
Stroke volume/EDV
Is an indicator of contractility.
How do you calculate cardiac output?
What is the average value?
SV * HR
Approximately 500ml/min in a 70Kg person (70ml sv and 72 bpm)
What on a chest x-ray can indicate heart failure?
Cardiomegaly - by cardiothoracic ratio above 50%
Pulmonary congestion - vascular opacity towards upper lobes (pulmonary odema), with upper lobe diversion (dilation of veins), fluid in fissures and Kerley B lines (horizontal white lines less than 2cm long in bases of lungs represent interseptal oedema)
What can be seen on an ECG that is indicative of heart failure?
- Ischemia - pathological Q waves
- Ventricular hypertrophy - Increase QRS amplitude, convex ST segment
- Arrhythmia (lack of P waves or A fib -due to cardiac dysfunction)
What can be seen on a echocardiography that is indicative of heart failure?
Abnroaml cardiac chamber dimension
Poor systolic and diastolic function
Regional wall motion abnormalities
Valvular disease - such as regurgitation or stenosis
Cardiomyopathies
What is a nuclear cardiology investigation?
And how might it indicate heart failure?
Radionucleotide angiography - radioactive tracer injected into blood vessels tracked through heart and vessels - ventricular ejection fraction.
SPECT or PET - demonstrate myocardial ischemia and viability in dysfunctional myocardium.
What is a cardiac MRI?
And how might it indicate heart failure?
Assess cardiac structure and function and viability in dysfunctional myocardium
Use dobutamine for contractile reserve (difference in contractility at rest compared to physiological stress) or use gadolinium for delayed enhancement which identifies fibrotic tissue (infarct imaging)
What is cardiac catheterisation?
How can it be used to indicate heart failure?
Coronary angiogram is an example
Uses iodine contrast dye to visualise blood vessels on x-ray images
Diagnosis - ischaemic HF and suitability for revascularization
Catheter often has a pressure sensor at the tip so can measure pulmonary artery pressure, left ventricular ED pressure and left atrial (wedge) pressure.