WEEK 4 Flashcards
What are the core values of a doctor?
Advocacy Caring Commitment Compassion Competence (most important) Integrity Spirit of enquiry
What sympathy and empathy are, and appreciate their value and limits
SYMPATHY = The quality or state of being affected by the condition of another with a feeling similar or corresponding to that of the other; the fact or capacity of entering into or sharing the feelings of another or others; fellow-feeling EMPATHY = ability to understand & appreciate another person's feelings, experience, etc
What are the 4 key attributes of care which must be maintained, whatever one’s values, as defined by GMC?
- Must act in accordance with relevant legislation
- Must not treat pts unfairly
- Must not deny pts access to appropriate services or care
- Must not cause patients distress
What are 4 arguments against the practice of conscientious objection & abortion?
- Inefficiency & inequity
- Inconsistency
- Commitments of a Dr
- Discrimination
What are the broad strategies upon which drug therapy is based?
- To increase cardiac contractility
- To decrease preload and/or afterload to decrease cardiac work demand by relaxing vascular smooth muscle & reducing blood volume
- Inhibit the RAAS
- Prevent inappropriate rise in HR
What are the problems associated with each of the compensatory mechanisms?
- Frank-starling:
- increase in vascular volume leads to increased EDV
=> increased muscle stretch & oxygen consumption - Sympathetic activity
Initially it’s helpful but long term it is not:
- tachycardia, vasoconstriction, decreased perfusion of tissues, cardiac arrhythmias, renin release
- decreases the workload of the heart => ischaemia, damage to myocytes, decreased contractility
- desensitisation of beta (but not alpha) receptors - Renin-angiotensin
- decrease in renal blood flow increases renin release
=> increased angiotensin II formation (it’s a vasoconstrictor plus stimulates aldosterone release)
=> sodium & water reabsorption is increased both directly & indirectly
- angiotensin II & aldosterone are involved in inflamm responses leading to deposition of fibroblasts & collagen in the ventricles => increases stiffness & decreases contractility of the heart, leading to myocardial remodelling & progressing dysfunction.
What are the 3 areas in which BMA support conscientious objection, and know which of these are legally protected?
Abortion
Fertility treatment
Withdrawal of life-sustaining treatment
Describe the NYHA (New York Heart Association Classification of Heart Failure)
I = No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea (shortness of breath).
II = Slight limitation of physical activity. Comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea (shortness of
breath).
III = Marked limitation of physical activity. Comfortable at rest. Less than ordinary activity causes fatigue, palpitation, or dyspnea.
IV = Unable to carry on any physical activity without discomfort. Symptoms of heart failure at rest. If any physical activity is
undertaken, discomfort increases.
What is the classification of systolic vs diastolic dysfunction based on?
Ejection fraction (%)
Describe (i) Systolic Ventricular dysfunction (ii) Diastolic ventricular dysfunction.
slide 6
Systolic dysfunction commonly results from conditions that affect what? (HINT: there’s 3 things)
- Contractility
- e.g. IHD, cardiomyopathy - Volume overload
- Pressure overload
- valvular stenosis, hypertension
What are the 4 causes of diastolic dysfunction?
- Impedance of ventricular expansion
- Increased wall thickness
- Delayed diastolic relaxation
- Increased HR
What are the causes of right ventricular dysfunction?
- Conditions impeding flow into the lungs
- pulmonary hypertension
- valve damage/stenosis/incompetence - Pumping ability of RV
- cardiomyopathy
- infarction - LV failure
- Congenital heart defects
What are the causes of left ventricular dysfunction?
- Hypertension (increase in TPR)
- Acute MI
- Aortic/mitral valve stenosis/regurgitation
- Increase in pulmonary pressure can lead to RV failure
What is the dominant cause of mortality in diabetic pts? Why do they think this is the case?
Cardiovascular complications
- due to elevated oxidative stress
Give examples of diabetes-associated metabolic disorders?
hyperglycemia hypertriglyceridemia hypercholesterolemia hypoalphalipoproteinemia increased levels of advanced glycation end products, glycated & oxidised lipoproteins
Give examples of systemic diseases that affects the CVS? (HINT: there’s 10)
Diabetes mellitus Hypertension COPD Amyloidosis Rheumatoid Arthritis Vasculitides & SLE Thyroid Disease Sarcoidosis Nutrition Drugs
What are the 4 examples of drugs that can affect the CVS?
anti-cancer
immunosuppressive
diabetogenic
anti-inflammatory
What is amyloidosis?
A group of rare but serious conditions caused by deposits of abnormal protein, called amyloid, in tissues and organs throughout the body
Amyloid is a description of proteins which have folded abnormally and then collected together. In this form they do not break down as easily as normal proteins and can build up in tissues and organs.
If this build-up causes the tissues or organs to stop working properly, the resulting conditions are called amyloidosis.
Define (i) stenosis (ii) incompetence.
(i) Narrowing of the valve outlet caused by thickening of valve cusps, or increased rigidity or scarring
(ii) (also known as insufficiency or regurgitation) caused by an incomplete seal when the valves close, allowing blood to flow backwards
What are the common causes of cardiac valve stenosis and incompetence? (HINT: there’s 3 categories)
- Congenital Heart Disease - bicuspid valve, atresia
- Cardiomyopathy (hypertrophic, dilated)
- Acquired - rheumatic fever, MI, age related (idiopathic aortic calcific stenosis), endocarditis
Define the term infective endocarditis.
The infection of a valve with the formation of thrombotic vegetations. The virulence of organisms determines the damage & severity
= is classified into acute & sub-acute
- bacteraemia is common
What are the the risk factors for infective endocarditis? (HINT: there’s 3)
- Valve damage - as before, especially rheumatic fever
- Bacteraemia - dental, catheterisation, 10% are unknown
- Immunosuppression
What is a vegetation.
A growth or excrescence of any sort. Specifically, a clot, composed largely of fused blood platelets, fibrin, and sometimes microorganisms, adherent to a diseased heart orifice or valve, and often initiated by infection of the structures involved
What are the local and systemic complications of infective endocarditis?
- cerebral & retinal emboli
- Bronchopneumonia, Pulmonary infarct
- Myocarditis
- Splenomegaly
- Anaemia
- Renal infarcts, glomerulonephritis
- Haematuria
LOCAL = clubbing & splinter haemorrhages
What are the principles of diagnosis, treatment and prevention of infective endocarditis?
Treat strep infection with antibiotics
Prophylactic cover for invasive procedures e.g. dental work
Replace damaged valves
Blood Cultures & IV antibiotics
What are the names of some organisms that cause infective endocarditis?
Group D streptococcus, gut commensald, skin strep (i.e. coxiella, fungi, candida)
What are the causes of ischaemic heart disease?
- Chronic coronary insufficiency
- Angina
- Unstable coronary disease
- MI, sudden ischaemic coronary - Heart Failure
- Arrhythmia
What are the macroscopic features of a coronary artery atheroma?
Fatty streak
Fibro-fatty plaque
Plaque disruption - plaque rupture, plaque erosion
What are the clinical features of acute myocardial infarction?
- Chest Pain
- severe, crushing radiating to jaw & arm - Associated “autonomic’ symptoms - nausea, sweating, terror
- Breathlessness
What are the pathological features of acute myocardial infarction?
- Plaque rupture (70-75%)
- Plaque Erosion (25-30%)
- Coronary embolism
- Coronary artery spasm/drugs
- Coronary anomaly
- Spontaneous coronary dissection
What are the complications associated of acute myocardial infarction?
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What are the clinico-pathological features of chronic ischaemic heart disease?
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What are dysrhythmias? Why may they arise?
Dysrhythmia describes conditions where the co-ordinated sequence of electrical activity in the heart is disrupted, Due to: changes in the heart cells, changes in the conduction of the impulse through the heart or a combo of the 2.
How are dysrhythmias classified?
Broadly classified as
- atrial (supraventricular)
- junctional (associated with AV node)
- ventricular
- tachycardias or brachycardias
What are the 2 commonest types of tachyarrhythmia?
Atrial fibrillation Supraventricular tachycardia (SVT)
What 4 broad categories of events do dysrhythmias arise from?
- Heart block
- Ectopic pacemaker activity
- Delayed after-depolarisations
- Circus Re-entry
How does heart block arise?
It results from damage (usually ischaemia) to a part of the conducting system. It often affects the AV node - the only path for conduction between atria & ventricles
Impulses can either be slowed, partially blocked or completely blocked
How is Heart Block classified?
1st Degree HB - AV node is slightly affected & conduction slowed. Have an abnormally long P-R interval, otherwise every atrial depol (P wave) is passed to the ventricles (QRS)
2nd Degree - more serious damage to AVN => partial block where only some of the atrial depol lead to ventricular depol (QRS)
3rd Degree - AVN completely blocked, no conduction progresses to ventricles. Atria depol (&beat) at inherent rate & the ventricles depol (&beat) at a pace set by Purkinje fibres
What are the subtypes of second degree heart block? (HINT: there’s 3 subtypes)
MOBITZ (type2) - most beats conducted with a constant P-R, but occasional an atrial depol without a ventricular depol
2:1 or 3:1 - describes ratio of P waves to QRS complexes
WENCKEBACH - Progressive lengthening of P-R interval until a P wave fails to produce a QRS complex. The P-R interval then shortens & normal conduction occurs before the P-R interval starts to lengthen again
The spontaneous electrical discharge of the SAN is from the combined effect of what 3 things?
- Decrease in K+ outflow
- Funny Na+ current
- Slow inward Ca2+ current
What are the ways/reasons that other areas of the heart can develop pacemaker activity? (HINT: there’s 4 ways)
- If damaged (ischaemia, CHD, rheumatic heart disease, hypertension etc)
- increased sympathetic activity (stress, exercise etc)
- Increased sensitivity to catecholamines (GA, caffeine, hyperthyroidism etc)
- Cardiac glycoside toxicity
What is early after-depolarisation?
Occurs towards the end of phase 2 (plateau due to inwards Ca2+). Results in a prolonged QT
It is triggered by fluctuating increases in Ca2+ permeability
Can set off self-sustaining depolarisations
What are delayed after-depolarisations?
Following every AP, some of the Ca entering in phase 2 has to be removed back to ECF (done via ca/3Na exchange). Normally a net influx of + & insignificant depolarisation.
If Ca intracellularly rises, the after-depol can get increasingly larger & become self-perpetuating (triggering AP)
Delayed repol increases Ca intracellularly which leads to increased after-depol & can lead to dangerous ventricular dysrhythmias
What is circus re-entry movements?
When an electrical impulse can re-stimulate (re-enter) a region of the heart AFTER its refractory period has passed
Comes from an unusual direction & before the tissue would have been re-stimulated by the next normal impulse from the SAN
- either a unidirectional block or a transient block can generate these circus re-entries
the differences in the electrical activity of the different parts of the heart and between normal and abnormal pacemaker cells which allow antidysrhythmic drug treatment
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