Week 4 Flashcards
What 6 questions do you think about from any paper?
- When and where was it published?
- Why was it conducted?
- Who conducted the research?
- Where was it conducted?
- How was it conducted?
- What were the results and take home message?
What is the difference between sympathy and empathy?
SYMPATHY- quality/state of being affected by the condition of another with a feeling similar. Capacity of entering or sharing the feelings of another.
EMPATHY- the ability to understand and appreciate another person’s feelings, experience etc
What care must a doctor provide according to GMC?
- Must act in accordance with relevant legislation
- Must not treat patients unfairly
- Must not deny patients access to appropriate services or care
- Must not cause patients distress
- You must not refuse to treat a particular patient because of personal belief
When do the BMA support doctors freedom of choice/ Conscientious Objection (3)?
- Abortion
- Fertility treatment
- Withdrawal of life-sustaining treatment
What does the Abortion Act, 1967 say about conscientious objection and abortion?
Nothing shall affect any duty to participate in treatment which is necessary to save the life or to prevent grave permanent injury to the physical or mental health of a pregnant woman
How do Human Rights Acts come into play?
- Everyone has the right to freedom of thought, conscience and religion.
- Freedom to manifest one’s religion or beliefs shall be subject only to such limitations… in the interests of public safety, for the protection of public order, health or morals or protection of right and freedoms of others
How does CO affect medical students?
- You also have the right to hold a conscientious objection to some types of treatment and you should discuss this with your medical school
- Treating patients fairly and communicating in a polite way, not expressing your personal beliefs
- Do not discriminate!
What are the 4 arguments against the practice of CO?
- Inefficiency and inequity
- Inconsistency
- Commitments of a doctor
- Discrimination
What is Pre-load?
Determined by venous return and EDV (end diastolic volume)
What is afterload?
Force the contracting heart must generate to eject blood from the heart depending on vascular resistance and ventricular wall tension
What is myocardial contractility dependent on (inotropy)?
Influenced by Ca2+:
- L type channels (opening faciliatated by cAMP)
- Na+/Ca2+ exchange (inhibited indirectly by cardiac glycosides)
What is the difference between systolic and diastolic dysfunction?
SYSTOLIC ventricular dysfunction - impaired cardiac contractility, thus a decreased ejection fraction. (less than 40%)
DIASTOLIC ventricular function - normal ejection fraction but impaired diastolic ventricular relaxation and decreased filling, meaning a decrease in stroke volume and cardiac output.
What does systolic dysfunction lead to?
- Contractility problems such as cardiomyopathy and ischaemic heart disease
- Volume overload
- Pressure overload such as in valvular stenosis and hypertension.
- Results in increased EDV (preload), ventricular dilation and increased ventricular wall tension
What causes systolic dysfunction?
- MI and transient myocardial ischaemia
- Mitral regurgitation
- Aortic regurgitation
- Severe hypertension
- Aortic stenosis
(all REDUCE ejection fraction)
What causes diastolic dysfunction?
- Left ventricular hypertrophy
- Myocardial fibrosis
- Transient myocardial ischaemia
- Pericardial constriction or tamponade
(all PRESERVE ejection fraction but DECREASE SV and CO)
What is the effect of right heart failure?
- Congestion of peripheral tissues as increased preload.
- Leads to oedema and ascites, liver congestion and GI tract congestion which may lead to anorexia and GI distress
What is the effect of left heart failure?
- Decreased cardiac output which leads to intolerance of activity and decreased tissue perfusion, leading to cyanosis and hypoxia (deficiency of oxygen reaching tissues)
- Also get pulmonary congestion, which leads to orthopnea (breathlessness when flat), paroxysmal nocturnal dyspnea and cough with frothy sputum
What are the causes of right heart failure?
- Conditions impeding flow into lungs such as pulmonary hypertension and valve damage/stenosiss
- Infarction of cardiomyopathy in right ventricle
- Left ventricular failure
- Congenital heart defects
What are causes of left heart failure?
- Hypertension
- Acute MI
- Aortic or mitral stenosis or regurgitation
What are the compensatory mechanisms for heart failure?
- Renin-angiotesin-aldosterone
- Frank-Starling
- Sympathetic nerve activity
- Fluid movements
What is the problem with the Frank Starling mechanism?
- Increase in vascular volume leads to increased EDV
- Increase in muscle stretch and oxygen consumption leads to decline of SV as we go past optimum sarcomere length.
- Flattened curve in contractility of heart in heart failure, even though EDV increases, CO does not increase comparatively, increase pressure.
What is the problem with sympathetic activity as a compensatory mechanism?
- Leads to tachycardias, decreased perfusion of tissues, cardiac arrythmias and renin release
- This leads to increased workload on the heart, leading to ischaemia and damage to myocytes.
- Get desensitisation of beta receptors
What is the problem with renin angiotensin compensatory mechanism?
- Decrease in renal blood flow stimulates release of renin, increasing angiotensin II formation. This is a vasoconstrictor and stimulates aldosterone release
- Thus there is sodium and water resportion which is increased both by decreased flow rate through kidneys and indirectly via aldosterone
- Angiotensin II and aldosterone are also involved in inflammatory responses leading to deposition of fibroblasts and collagen in the ventricles, increasing stiffness and decreasing contractility of the heart
What 4 strategies would be used for treatment?
- Increasing cardiac contractility
- Decreasing preload and or after load by relaxing smooth muscle and reducing blood volume
- Inhibit the RAAS
- Prevent inappropriate increase in heart rate
What is the Definition of Heart Failure?
- Failure of the heart to pump sufficient blood to satisfy metabolic demands
- Results in under-perfusion which causes fluid retention and increases blood volume
What is Acute Heart Failure?
Rapid onset of symptoms, often with definable cause ie. Myocardial infarction
What is Chronic Heart Failure?
Slow onset of symptoms, associated with, ischaemic or valvular heart disease
What is Acute-on-Chronic Heart Failure?
Chronic failure becomes worsened by an acute event
List Systemic Diseases which have an affect on the CVS?
- Diabetes Mellitus
- Hypertension
- Chronic Obstructive Pulmonary Disease
- Amyloidosis
- Rheumatoid Arthritis
- Vasculitides & SLE
- Thyroid disease
- Sarcoidosis
- Nutrition
- Drugs
What is “forward failure”?
Reduced perfusion of tissues, more associated with advanced failure
What is “backwards failure”?
Due to increased venous pressures, dominated by fluid retention and tissue congestion
What happens pathologically when there is too much circulating glucose (diabetes mellitus)?
- Non-enzymatic glycation occurs
- Glucose is in excess so sticks to proteins and membranes
Which protein is an ideal marker for blood glucose control in diabetics?
Glycated Heamoglobin
What would be classed as a primary cause of hypertension?
Cardiovascular disease
How does emphysema cause ischaemic damage to the heart?
Vessels within the scar tissue within the lungs are non-functional and present a high resistance for blood to force through, this increases the workloads of the right side of the heart, which causes pulmonary hypertension and right ventricular hypertension- leading to ischaemic damage to the heart muscle
What is amyloid and what does it do?
- Extracellular beta-pleated sheet material
- Deposited on organs, impairing it’s function
What pathologcial condition produces AA and what does this stand for?
AA= amyloid associated protein
Chronic inflammation produces excess amyloid associated proteins
What pathological condition produces AL and what does this stand for?
AL= amyloid light chains
Myeloma produces excess amyloid light chains (related to immunoglobulin)
What is vaculitis?
Damage to blood vessels due to hyper sensitivity
What is type 1 hypersensitivity?
Allergic reaction
If a middle aged, possibly overweight, female patient presents with a cold, what diagnosis should be kept in mind?
Hypothyroidism
What is sarcoidosis?
Abnormal collections of inflammatory cells that form nodules in multiple organs
What could have happened in a patient with sarcoidosis and arrthymia?
Granuloma formed in the conducting tissue
List Drugs that affect CVS?
- Anti-cancer
- Immunosuppressive
- Diabetogenic
- Anti-inflammatory
What are the valve components (4)?
- Valve rings
- Cusps
- Chordae tendiniae
- Papillary muscles (mitral/tricuspid only)
Define stenosis of valve?
Narrowing of valve outlet caused by thickening of valve cusps, or increased rigidity/scarring
Define valve incompetence?
Insufficency or regurgitation caused by incomplete seal when valves close, allowing blood to flow backwards
What are vegetations?
- Something growing on valve
- Platelets and fibrin accumulations that form hard plaque
What are the three main causes of cardiac valve stenosis and incompetence
- Congenital heart disease
- Cardiomyopathy
- Acquired
What types of valve problems would be expected from congenital heart disease?
Bicuspid valve incompetence or atresia
What types of problems in valves are found with cardiomyopathy?
Incompetence from hypertophic heart, therefore dilated valve ring
What sorts of things can cause acquired valve problems?
- Rhematic fever
- MI
- Age related (idiopathic)
- Endocarditis
What are the risks of aortic stenosis?
- Left ventricular hypertrophy
- Syncope
- Sudden cardiac death
What are causes of aortic stenosis?
- Calcification of congenital biscuspid valve
- Senile calcification degeneration
- Rheumatic fever
What is rheumatic fever?
- An inflammatory disease that can involve the heart, joints, skin, and brain.
- Typically develops 2-4 weeks after a throat infection from Streptococcus pyogenes.
- The heart is involved in about half of cases
What are the consequences of aortic stenosis?
- Increases the work of the heart
- Ventricular hypertrophy
- Causes cardiac failure
(symptoms: dyspnoea, angina, syncope)
What are causes of aortic valve incompetence?
- Marfan’s syndrome
- Rheumatic fever
- Infective endocarditis
- post MI
What are the consequences of aortic valve incompetence?
- Aortic regurgitation
- Increases volume of blood to be pumped significantly
- Increases the workload of the heart
- Causes left ventricular hypertrophy and cardiac failure
What are the causes of mitral valve incompetences?
Cusp/chordae- rheumatic disease scarring/contraction, floppy valve & marfans, infective endocarditis (perforation)
Papillary muscles- post MI
Valve ring- age
What is almost always the cause of mitral valve incompetence?
Childhood rheumatic fever
What are the risks of Mitral valve incompetence?
Pulmonary hypertension, and so right ventricular hypertrophy
What are the 2 main causes of mitral valve stenosis?
- Congenital
- Post rheumatic fever
What is the consequence of mitral valve stenosis?
- Restricts blood flow to left ventricle
- Atrial fibrillation
- Back pressure causes pulmonary hypertension and finally right heart failure
Define infective endocarditis?
- Infection of valve with formation of thrombotic vegetations.
- Virulence of organisms determines damage and severity.
- Classed as acute and subacute
- Bacteraemia is common
What is the biggest risk factor for infective endocaridits?
Rheumatic fever in childhood
Name the 3 main risk factors for infective endocarditis
- Valve damage- especially in rheumatic fever
- Bacteraemia (dental, catheterisation)
- Immunosupression
Describe the principles of diagnosis and treament of infective endocarditis?
- Initially treat strep. infection
- Prophylatic antibiotics in at risk patients for invasive procedures (like dental work)
- Replacement of damaged valves
- Imaging, blood cultures, clinical signs
What is the most common cause of CVS?
Smoking
What does atherosclerotic coronary disease cause?
- Chronic coronary insuficciency (Angina)
- Unstable coronary disease (MI, sudden ischaemic coronary disease)
- Heart failure
- Arrythmia (acute is ischaemic, scar related)
What surface of the heart do the coronary arteries lie on?
Epicardial (outer surface of the heart)
What causes resistance in coronary arteries?
Presence of atheromas
Where does ischaemia occur first in the heart?
Subendocardial region (water shed area) when there is no cell death.
How can the coronary arteries be imaged?
- Coronary Angiography
- CT
- MR imaging (more functional but not as much accuracy)
What is the usual pathology of atherosclerotic coronary artery disease?
- Fatty streak (already found in young people)
- Fibro fatty plaques
- Plaque disruption
- Plaque rupture & plaque erosion
What are the risk factors for atherosclerotic coronary arteries?
Age Hypertension Hypercholesterolaemia Smoking Diabetes Obesity Physical Inactivity
What is the histology of coronary atherosclerosis?
Lipid rich core, fibrous cap and a lumen
What is the mechanism of coronary atherosclerosis?
- LDL becomes oxidised and taken up by a macrophage
- Macrophage responds to it thinking it is a germ, eats it and stores the fat in lysosomes
- In fibro fatty plaques, cytokines drive macrophage to form the fibrous cap
What is Angina and how does it present?
- It presents as: Gripping central chest pain, radiation to arm and jaw.
- Clear and precise relationship to exercise.
- Worse after food and in the cold.
- No autonomic features and flat of hand to describe pain.
- The cause is sub endocardial ischaemia.
- ECG shows depression in the ST segment
What is the mechanism of Angina?
Mismatch of blood supply to demand because of epicardial stenosis.
Supply = coronary blood flow
Demand = myocardial oxygen consumption
50% of the lumen diameter reducing usually signifies limitation of maximal flow. Coronary flow reserve must always be able to accomodate myocardia 02 demand. Angina is when it becomes inadequate.
What is Coronary Flow Reserve?
Coronary flow reserve (CFR) is the maximum increase in blood flow through the coronary arteries above the normal resting volume
What are two regulatory systems of coronary circulation?
- Autoregulation (myogenic control, where blood flow is kept constant)
- Metabolic regulation (Blood vessels sense the changes in BP)
How does exercise affect myocardial blood flow?
Rise up to 5 fold to accommodate a 20 fold increase in total body 02 consumption