For Phase 1a Maria Digby & Rowena Speak Cardiology The Peer Teaching Society is not liable for false...
-
Upload
calvin-clarence-shelton -
Category
Documents
-
view
216 -
download
3
Transcript of For Phase 1a Maria Digby & Rowena Speak Cardiology The Peer Teaching Society is not liable for false...
For Phase 1a
Maria Digby & Rowena Speak
Cardiology
The Peer Teaching Society is not liable for false or misleading information…
1st Half* Physiology* Pharmacology* Anatomy* ECG
2nd Half* Pathophysiology + Clinical Scenarios* More Pharmacology!* Question time
What we’re going to cover…
The Peer Teaching Society is not liable for false or misleading information…
Ventricles
The Peer Teaching Society is not liable for false or misleading information…
* Phase 0: depolarisation – Na+ in
* Phase 1: partial repolarisation – Na+ channels shut, K+ out
* Phase 2: plateau – Ca2+ in through L-type channels
* Phase 3: repolarisation – K+ out
* Phase 4: resting potential – (-90mV) – Na+/K+ ATPase
SAN
The Peer Teaching Society is not liable for false or misleading information…
* Phase 4 = pacemaker potential – less K+ out, Na+ in through F-type channels, Ca2+ in through T-type channels
* Phase 0 = slower depolarisation – Ca2+ in through L-channels NOT Na+ in like depolarisation ventricles!)
* Phase 3 = repolarisation – K+ out
Antiarrhythmic drugs: Vaughan Williams classification
The Peer Teaching Society is not liable for false or misleading information…
* Class I: Na+ channel blockers1a) Quinidine – moderate blocker 1b) Lignocaine – weak blocker1c) Flecainide – strong blocker
* Class II: Beta blockers: block sympathetic stimulation - atenolol
* Class III: K+ channel blockers: prolong repolarisation - amiodarone
* Class IV: Ca2+ channel blockers: verapramil
I
IV
Phase 4
Phase 0
Phase 1
Phase 2
Phase 3
0 mV
-80mV
II
III
Cardiac cycle
The Peer Teaching Society is not liable for false or misleading information…
- AP = aortic pressure- LVP = left ventricular
pressure- LAP = left atrial pressure- LVEDV = left ventricular
end diastolic volume- LVESV = left ventricular
end systolic volume
Cardiac cycle: Systole
The Peer Teaching Society is not liable for false or misleading information…
• Systole
- After ventricular filling, pressure in ventricles > in atria = AV valves close (SOUND 1 = “lub”)
1. Isovolumetric contraction: ventricles contracts when all valves are shut (this increases pressure in ventricles)
2. Ventricular ejection: pressure in ventricles > in pulmonary artery/aorta = semilunar valves open and blood flows out of ventricle
Cardiac cycle: Diastole
The Peer Teaching Society is not liable for false or misleading information…
• Diasystole
- After ventricular ejection, pressure in pulmonary artery/aorta > than in ventricles = semilunar valves shut (SOUND 2 = “dub”)
1. Isovolumetric relaxation: ventricles relax when all valves are shut (this decreases the pressure in the ventricles)
2. Ventricular filling: pressure in ventricles < in atria = AV valves open
Cardiac cycle: “atrial kick”
The Peer Teaching Society is not liable for false or misleading information…
• Ventricular filling is mostly a passive process
• But towards the end of diastole, the atria contract causing a small increase in pressure in the ventricles = “atrial kick”
Cardiac cycle: dicrotic notch
The Peer Teaching Society is not liable for false or misleading information…
• When the aortic valve closes, blood rebounds against the valve causing a decrease then a rebound of aortic pressure = dicrotic notch
Equations: learn these!!
The Peer Teaching Society is not liable for false or misleading information…
* SV = EDV - ESV* CO = HR x SV* MAP = DP + 1/3(SP-DP)* BP = CO x TPR
Monitoring MAP: Baroreceptors
The Peer Teaching Society is not liable for false or misleading information…
Where are the arterial baroreceptors?
a) Carotid sinus + b) Aortic arch
Baroreceptors detect changes in arterial pressure Afferent nerve (Glossopharyngeal) CNS (Medullary Cardiovascular Centre) Efferent nerve i. Sympathetic outflow to heart and arterioles ii. Parasympathetic (Vagus) outflow to heart
Maintaining MAP (BP = CO x TPR)
The Peer Teaching Society is not liable for false or misleading information…
BP
CO TPR
Maintaining MAP: 1. Changing CO
The Peer Teaching Society is not liable for false or misleading information…
CO = HR x SV
Change Heart Rate* Sympathetic nervous
stimulation of the heart* Parasympathetic nervous
stimulation of the heart (Vagus)
* Plasma adrenaline
Change Stroke Volume* Sympathetic nervous
stimulation of the heart* Plasma adrenaline* End-diastolic ventricular
volume (preload) – FRANK-STARLING MECHANISM
FRANK-STARLING MECHANISM – learn this!
The Peer Teaching Society is not liable for false or misleading information…
At any given heart rate….
Any ↑ Venous Return….
Causes ↑ End-Diastolic Volume…
Causes ↑ stretch in the cardiac muscle (Preload)…
Causes ↑ forceful contraction…
Which ↑ Stroke Volume and thereby the Cardiac Output
Maintaining MAP: 2. Changing TPR
The Peer Teaching Society is not liable for false or misleading information…
The arterioles are the principle site of resistance to blood flow
Vasoconstriction* Local: Endothelin-1, internal
blood pressure (myogenic response)
* Neural: Sympathetic nerves* Hormonal: Adrenaline (on
alpha receptors), Angiotensin II, Vasopressin (aka Antidiuretic hormone)
Vasodilation* Local: decrease in Oxygen,
increase in CO2/H+, Nitric Oxide, Eicosanoids, Prostacyclin
* Neural: Neurons that release Nitric oxide
* Hormonal: Adrenaline (on beta 2 receptors), Atrial Natriuretic Peptide
Important point…
The Peer Teaching Society is not liable for false or misleading information…
* There is sympathetic stimulation to both the heart and arterioles
* But there is no parasympathetic stimulation to the arterioles, only to the heart
Terms to understand…
The Peer Teaching Society is not liable for false or misleading information…
Active hyperaemia – vasodilation in response to an increase in metabolic activity
Flow autoregulation – vasodilation in response to decreased pressure
Reactive hyperaemia – when a tissue’s blood supply has been completely occluded, on removal of the occlusion there is a profound, transient increase in blood flow
GO LOOK AT…
The Peer Teaching Society is not liable for false or misleading information…
VANDERS - especially page 399 (12th edition)
Long term regulation of MAP
The Peer Teaching Society is not liable for false or misleading information…
The Baroreceptor reflex is a short term regulator. They end up adapting to a maintained change in pressure.
The most important long-term regulator of arterial pressure is blood volume – this is regulated by the Renin-Angiotensin-Aldosterone System (RAAS)
ACE inhibitors inhibit RAAS to reduce blood volume
(have a quick look at RAAS – try to understand it but don’t worry about memorising it until Phase 1b!)
Haemostasis
The Peer Teaching Society is not liable for false or misleading information…
1. Platelet plug2. Clotting cascade
* Clotting factors dependent upon Vitamin K: II, VII, IX, X
* Haven’t got time to talk about this now – make sure you understand the principles of it
* Important for understanding pharmacology of Aspirin, Clopidogrel, Warfarin, Heparin and Fibrinolytics
Anatomy - valves
The Peer Teaching Society is not liable for false or misleading information…
Valve Surface marking Auscultation area
Tricuspid 4th intercostal space-midline
5th intercostal space-right and left sternal edge
Pulmonary 3rd costal cartilage-sternal junction-left
2nd intercostal space-left sternal edge
Mitral 4th intercostal cartilage-midline
5th intercostal space-left, midclavicular line
Aortic 3rd intercostal space-left half of sternum
2nd intercostal space-right sternal edge
Valve pathology
The Peer Teaching Society is not liable for false or misleading information…
Pathology Cause MurmurMitral stenosis Rheumatic fever Mid-diastolic
Mitral regurgitation Ischaemic heart disease, MI, Rheumatic fever
Pan-systolic
Aortic stenosis Calcific valve disease, Rheumatic fever
Ejection-systolic
Aortic regurgitation Rheumatic fever, bicuspid aortic valve
Diastolic
Rheumatic fever
The Peer Teaching Society is not liable for false or misleading information…
• Endocarditis • Post-Streptococcus pyogenes infection• (Scarlet fever, Strep throat)• Damages heart valves
Anatomy – heart borders
The Peer Teaching Society is not liable for false or misleading information…
Right: formed by right atrium, runs between 3rd and 6th right costal cartilages approximately 2-3cm from the midline in the adult
Left: formed by left atrial appendage + left ventricle, apex 2nd left intercostal space 2-3cm from midline
Inferior: formed by right atrium and right ventricle + tiny bit of left ventricle
Anatomy – aorta
The Peer Teaching Society is not liable for false or misleading information…
Thoracic* Right + left coronary arteries* Brachiocephalic (aka innominate)
artery* Left common carotid artery* Left subclavian artery
Passes through diaphragm at T12
Abdominal* Abdominal aortic aneurysm –
expansile, pulsatile mass, midline, above umbilicus
Bifurcates at L4
Electrocardiography (ECG) – heart rate
The Peer Teaching Society is not liable for false or misleading information…
Heart Rate– Quick estimation = 10 x no. of QRS complexes on
one rhythm strip (check speed of ECG is 25mm/s)
• Sinus bradycardia < 60bpm• Sinus tachycardia >100bpm• Normal PR interval = 0.12-0.20s• Normal QRS complex = 0.08-0.12s
ECG – AV block
The Peer Teaching Society is not liable for false or misleading information…
1st degree – PR interval prolonged, >0.20sec
2nd degree:-1. Mobitz type I - progressive lengthening of PR interval with
each successive complex until a P wave is not conducted2. Mobitz type II – PR interval constant, QRS complexes
dropped intermittently or in fixed ratio to P wave rate
3rd degree - Complete dissociation of P Waves and QRS complexes
ECG
The Peer Teaching Society is not liable for false or misleading information…
Atrial flutter = saw tooth pattern
Atrial fibrillation = irregularly irregular rhythm
ECG – Ventricular fibrillation: fine and coarse
The Peer Teaching Society is not liable for false or misleading information…
Ventricular fibrillation
Useful websites
The Peer Teaching Society is not liable for false or misleading information…
• http://www.cvphysiology.com• http://www.cvpharmacology.com/
Pathology/Pathophysiology
• Normal arterial structure
The Peer Teaching Society is not liable for false or misleading information…
Getting old ain’t pleasant
• Progressive fibrous thickening of intima
• Fibrosis + scarring of muscular or elastic media
• Accumulation of mucopolysaccharide-rich ground substance
• Fragmentation of elastic laminae
• ATHEROSCLEROSIS
The Peer Teaching Society is not liable for false or misleading information…
Atherosclerosis
Some predisposing factors?
Prevented?
The Peer Teaching Society is not liable for false or misleading information…
Atherosclerosis
• Effects medium and large arteries
Risk factors:• Aging• Male • Hypertension • Smoking • Diabetes mellitus
• Hyperlipidemia • Increase LDL• Decreased HDL• Having a factor 7
genetics• Lifestyle- Exercise - Obesity- Diet- Stress and personality
The Peer Teaching Society is not liable for false or misleading information…
Drugs – ‘all’s well that ends well’ ;)
• Drugs• Calcium channel blockers “ipine”s eg:
amlodipine• ACE Inhibitors “il”s eg: ramipril• Angiotensin Receptor Blockers “sartans” eg:
candesartan• Diuretics “ide”s eg: loop – furosemide,
thiazide – bendoflumethiazide and K sparing - Amiloride
• Beta blockers “olol”s eg: atenolol• Statins “statin”eg: simvastatin
The Peer Teaching Society is not liable for false or misleading information…
• Clopidogrel - is an oral, thienopyridine class antiplatelet agent
• Anticoagulants “rin” eg: warfarin and heparin
• NSAIDS “profen” eg: ibuprofen, aspirin *so doesn’t work for everything
The Peer Teaching Society is not liable for false or misleading information…
Angina Pectoralis
• Caused by chronic heart disease
• Atherosclerosis in the coronary artery
• Means less O2 to heart muscle
• Crushing chest pain • No troponin • No new changes on
ECG
• Stable or unstable? • Stable - Caused by activity / stress (watching Barnsley)- relieved by GTN/rest• Unstable - NOT relieved by GTN /rest - Can occur at rest
The Peer Teaching Society is not liable for false or misleading information…
MI
What is an MI? How does it occur?How does it present? How is it prevented?
• ST elevation myocardial infarction
• Non-ST elevation myocardial infarction
The Peer Teaching Society is not liable for false or misleading information…
MI - STEMI
• Crushing chest pain • Feeling of
“impending doom” in Barnsley – “gonna miss Barnsley play at weekend” ;)
• Nausea • Sweating• SOB• Clammy skin
• Raised Troponin level
• ST elevation on ECG
The Peer Teaching Society is not liable for false or misleading information…
MI - STEMI
• STEMI • Ambulance • MONA
• A and E • β blocker (atenolol)• Thrombolytics (tPA
or streptokinase)• ACE inhibitor
(lisinopril)• Clopidogrel
• Back at home• Warfarin• Aspirin• β Blocker
(metoprolol)• ACE inhibitor• Statin (simvastatin)
The Peer Teaching Society is not liable for false or misleading information…
MI - NSTEMI
• Infarct • Feeling again same
“impending doom” - Barnsley be relegated?
• Nausea • Sweating• SOB • Clammy skin
• Raised Troponin• No new ECG
changes
The Peer Teaching Society is not liable for false or misleading information…
MI - NSTEMI
NSTEMI Ambulance • MONA• M= Morphine • O = Oxygen• N = Nitrates• A = Aspirin
A and E • β blocker (atenolol)• LMW heparin• GPIIb/IIIa antagonist
(tirofiban)• Nitrates• Clopidogrel Back at home • Warfarin• Aspirin• β Blocker (metoprolol)• ACE inhibitor • Statin
The Peer Teaching Society is not liable for false or misleading information…
Heart Failure
• Heart failure = pathophysiological state in which the heart is unable to pump sufficient blood to meet the needs of the metabolising tissues or can only do so with elevated filling pressures
• R, L or Congestive • Systolic / diastolic /Both• Excessive salt and water retention• Low cardiac output and raised peripheral
resistance
The Peer Teaching Society is not liable for false or misleading information…
Causes:- 1. Ischaemic heart disease – 34%2. Dilated cardiomyopathy – 32% 3. Primary valvular disease and
congenital heart disease – 12% 4. Hypertensive heart disease – 11% 5. Other -5%
The Peer Teaching Society is not liable for false or misleading information…
• Physiological– A state where the heart is unable to
pump enough blood to satisfy the needs of the metabolising tissues
• Clinical– A symptomatic condition where
breathlessness, tiredness and fatigue are associated with a cardiac abnormality that reduces cardiac output
The Peer Teaching Society is not liable for false or misleading information…
Key concepts - Pathophysiology
1. Initial insult2. Fall in cardiac output 3. ↑Preload to maintain ventricular
performance4. ↑Afterload limits ventricular performance5. Maladaptive hormonal responses6. Progressive left ventricular remodelling 7. Progressive decline in cardiac
performance
The Peer Teaching Society is not liable for false or misleading information…
Left heart failure
• Symptoms:
• fatigue,
• exertional breathlessness,
• orthopnoea
• paroxysmal nocturnal dyspnoea
• Signs: (occur late)
• cardiomegaly,
• added heart sounds,
• tachycardia,
• crackles in lung bases
The Peer Teaching Society is not liable for false or misleading information…
Right heart failure
• Symptoms:
• -swollen ankles, fatigue, anorexia
• Signs: (occur early)
• -raised jugular venous pressure
• -hepatomegaly
• -pitting oedema
• -ascitesThe Peer Teaching Society is not liable for false or misleading information…
Congestive
• A mixture of both left and right heart failure!
• Almost always right heart failure secondary to severe left heart failure…
The Peer Teaching Society is not liable for false or misleading information…
Tetralogy of Fallot
• Congenital defect – most common form of cyanotic congenital heart disease
Causes:-Low O2 levels in the blood leading to cyanosis
The Peer Teaching Society is not liable for false or misleading information…
Classic form includes 4 defects of the heart and its major blood vessels
1. Ventricular septal defect 2. Narrowing of the pulmonary outflow
tract3. Overriding aorta - shifted over to
the RV and ventricular septal defect (usually just from LV)
4. Right ventricular hypertrophy
The Peer Teaching Society is not liable for false or misleading information…
Factors that increase risk
• Alcoholism in mother • Diabetes • Mother who is over 40 years old• Poor nutrition during pregnancy• Rubella or other viral illnesses during
pregnancy • Children more likely to have Downs
syndrome
The Peer Teaching Society is not liable for false or misleading information…
Symptoms
• Cyanosed (blue skin)• Clubbing of fingers • Difficulty feeding • Failure to gain wt• Passing out • Poor development • Squatting during episodes of
cyanosis
The Peer Teaching Society is not liable for false or misleading information…
Signs and tests• Chest Xray• Complete blood count • ECHO • MRI (usually after surgery)TreatmentSurgery to repair tetralogy of Fallot is done when the infant is very youngOutcome – 90% survive to adulthood and live an active, healthy and productive life• Do have to have regular cardiology
appointments The Peer Teaching Society is not liable for false or misleading information…
Problem solving time
• 50 year old man presents with “crushing chest pain”, he was rushed in to AandE from the local Barnsley vs Owls, smoker for 35 years, the chest pain radiates to his jaw. He feels sweaty, nauseous and vomited.
The Peer Teaching Society is not liable for false or misleading information…
a) MIb) Angina c) Tetralogy of Fallotd) Right heart failuree) Football fever
The Peer Teaching Society is not liable for false or misleading information…
• 80 year old retired postman complains of severe onset central chest pain which comes on when he is walking his cat Jess. He sometimes gets it when sitting reading the sports section of the Barnsley Chronicle.
• Any ideas?
The Peer Teaching Society is not liable for false or misleading information…
a) MI b) Unstable Angina pectoralisc) Palpitationsd) Intermittent claudication e) Stable angina pectoralis
The Peer Teaching Society is not liable for false or misleading information…
• A 50 year old lady diabetic (type 2) complains of pain when walking in her calves and is relieved by rest.
• She used to smoke until 2 years ago and is a telesales rep
The Peer Teaching Society is not liable for false or misleading information…
a) Crampb) Intermittent Claudication c) DVT (deep vein thrombosis)d) Pulled a muscle e) Been stabbed in the leg in the past
The Peer Teaching Society is not liable for false or misleading information…