Acute coronary disease Flashcards
What is acute coronary syndrome
Any acute presentation of coronary artery disease
What are the characteristics of acute coronary syndrome (4)
dynamic stenosis
Supply-led ischaemia
Unpredictable
Dangerous
What is the pathogenesis of acute coronary syndrome (3)
plaque ruptures
Clot forms
Vessel is either partially or totally occluded
What factors can affect plaque rupture (6)
lipid content
Thickness of fibrous cap
Intraluminal pressure changes
Bending/twisting of artery
Shape
Mechanical injury
What can total vessel occlusion lead to
ST elevation MI
What can subtotal vessel occlusion lead to
Non-ST elevation MI
What are the three steps of the platelet cascade
Adhesion
Activation
Aggregation
How are platelets activated (4)
when platelets are exposed to a vascular injury, they release ADP and switch on cycloxygenase
Cycloxygenase generates thromboxane A2
ADP and thromboxane A2 bind to receptors on the surface of platelets
This activates the platelets
Other than platelets, what can be incorporated into a clot (3)
Fibrin
White blood cells
Red blood cells
What is the pain caused by STEMI like (5)
severe
Radiating
Crushing
Prolonged
Not relieved by GTN
What symptoms other than pain are associated with STEMI (3)
sweating
Nausea
Vomiting
What must be observed on an ECG for diagnosis as a STEMI (2)
an elevation of more than 1mm in two adjacent limb leads
Or
An elevation of more than 2mm in two contiguous precocial leads
What other abnormal features can be observed on an ECG due to a STEMI (3)
New onset bundle branch block
T wave inversion
Q waves
What mechanisms can be used to manage STEMIs (2)
preventing platelet activation
Fibrinolysis
What drugs can be used to prevent platelet activation in STEMI (2)
P2Y12 receptor antagonists (clopidogrel blocks ADP receptors on platelets)
Aspirin (inhibits cycloxygenase system)
What are the risks of using thrombolytic drugs to manage STEMIs (3)
Failure to re-perfuse
Haemorrhage
Hypersensitivity
What does reperfusion therapy include (2)
thrombolytic drugs
Percutaneous coronary intervention
What are the indications for reperfusion therapy (2)
Chest pain that suggests acute myocardial infarction
ECG changes
What are the contraindications of reperfusion therapy (6)
bleeding disorder
stroke
CNS damage/neoplasm
Internal bleeding
Aortic dissection
Trauma/surgery
What increases long-term mortality (in relation to management of STEMIs)
failed thrombolysis
When is thrombolysis used to treat STEMIs
If angioplasty is not available within 120 minutes
What complications can arise from acute myocardial infarction (4)
death
Arrhythmic complications
Structural complications
Functional complications
What are examples of structural complications arising from acute myocardia infarction (3)
Cardiac rupture
Ventricular septal defect
Mitral valve regurgitation
What observations are taken for an acute myocardial infarction (7)
pulse
Bp
Patient feeling
Heart sounds
Murmurs
Pulmonary crepitations
Fluid balance
What can be used to diagnose an NSTEMI
bio markers - troponin complex
Describe the troponin complex (3)
Globular protein complex
Found in thin myofilaments
Regulates muscle contraction
How are NSTEMIs managed (2)
stent
Dual-anti-platelet therapy
Which drug is preferred as the first agent in treatment of NSTEMIs
Clopidogrel
Describe characteristics of unstable angina (3)
symptoms suggestive of MI
No troponin I release
Usually no ECG changes
What is type one myocardial infarction
ischaemia due to a primary coronary event
What are the characteristics of type one MI (3)
major ECG changes
Higher troponin
Severe coronary artery disease
What is type two MI
secondary
Ischaemia due to imbalance of oxygen supply and demand
What can cause type two MI (2)
coronary embolism
Hypertension
What can cause type one MI
plaque rupture
What are the characteristics of type 2 MI (5)
less severe chest pain
Minor ECG changes
Mild-moderate coronary disease
Tachycardia
Low blood pressure
What is type three MI
sudden cardiac death with symptoms suggestive of ischaemia
What is controlled in secondary prevention of acute coronary syndrome (3)
blood pressure
Cholesterol
Diabetes
What are the four phase of cardiac rehabilitation
in-patient care
Early post-discharge period
Structured exercise program
Long term maintenance of physical activity and lifestyle changes
What are the target cholesterol levels in cardiac rehabilitation (2)
total < 4.0 mmol/l
HDL . 1.0 mmol/l
What are the types of atrial tachycardia (6)
Sinus tachycardia
Atrial fibrillation
Atrial flutter
AVNRT
AVRT
EAT
What are the types of ventricular arrhythmia (4)
ventricular fibrillation
Ventricular tachycardia
Premature ventricular complexes
Asystole
What are the types of bradycardia (3)
sinus bradycardia
Sinus pauses
Heart block
What does the level of threat to life posed by tachycardia depend on
how the arrhythmia affects cardiac output and blood pressure
What can be caused by haemodynamically unstable tachycardia (2)
syncope
Cardiac arrest
What can be caused by haemodynamically stable tachycardia (4)
hypotension
Reduced coronary circulation
angina
Heart failure
In what way can sinus tachycardia be non-pathological
Due to reflex changes in vagal tone during respiratory cycle
What is the management for sinus tachycardia (2)
treating underlying cause
Βeta blockers
What is idiopathic atria fibrillation (2)
Atrial fibrillation that occurs in the absence of any heart disease with no evidence of ventricular dysfunction
A diagnosis of exclusion
What increases incidence of atrial fibrillation
increasing age
When would a pacemaker be used to treat atrial fibrillation (2)
if atrial fibrillation with a slow ventricular rate coexists with periods of fast ventricular rate - to allow for pharmacological control of fast ventricular rate
If pharmacological fails/is not tolerated
What risks does atrial fibrillation pose (2)
thromboembolic stroke
Congestive heart failure
What are the possible causes of atrial fibrillation (8)
congenital
Genetic
Infection
Inflammation
Vascular
Metabolic
Structural
Lifestyle
What are the symptoms of atrial fibrillation (7)
palpitations
Presyncope
Syncope
Chest pain
Dyspnoea
Sweatiness
Fatigue
What are the patterns of atrial fibrillation (3)
paroxysmal
Persistent
Permanent
Describe paroxysmal atrial fibrillation (3)
<48 hrs
Limited period of time
Often recurrent
Describe persistent atrial fibrillation (3)
> 48hrs
Can be cardioverted to normal sinus rhythm
Unlikely to spontaneously revert to Norma sinus rhythm
Describe permanent atrial fibrillation
Normal sinus rhythm cannot be restored
Describe the appearance of atrial fibrillation on an ECG (4)
irregularly irregular QRS complexes
Absence of P waves
Presence of F waves
Atrial rate > 300bpm
how does atrial fibrillation affect the cardiac cycle (2)
Diastole time decreased
Therefore cardiac output is decreased
What treatment is used to restore rhythm in the event of atrial fibrillation (2)
anti-arrhythmic drugs
Direct current cardioversion (DCCV)
What treatment is used to maintain rhythm in the event of atrial fibrillation (3)
Anti-arrhythmic drugs
Catheter ablation (of atrial focus/pulmonary veins)
Surgery
What is used to control heart rate in the event of atrial fibrillation (4)
digoxin
Beta blockers
Verapamil
Diltiazem
What class of drug must be used in atrial fibrillation if there is a high risk for stroke
anticoagulants
What is atrial flutter(2)
a rapid and regular form of atrial tachycardia
Sustained by a macro-re-entry circuit (usually confined to right atrium)
what does atrial flutter carry the risk of
Thromboembolic stroke
What can chronic atria flutter often progress to
atrial fibrillation
How is atrial flutter treated (4)
radiofrequency ablation
Pharmacological therapy
Cardioversion
Oral anti-coagulant
How does supraventricular tachycardia present on an ECG
Narrow QRS complex
How is acute supraventricular tachycardia treated
increasing vagal tone and slowing atrioventricular node conduction
Us using IV adenosine and IV verapamil
How is chronic supraventricular tachycardia treated (4)
avoiding stimulants
Elecrophysiological study (and radiofrequency ablation)
Beta blockers
Anti-arrhythmic drugs
What are the types of atrioventricular tachycardia (2)
atrioventricular nodal re-entrant tachycardia
Atrioventricular re-entrant tachycardia via accessory pathway
Where may ventricular tachycardia originate (2)
ventricular myocardium
Fascicles of the conducting system
How does ventricular tachycardia show up on an ECG and why
wide QRS complex
As arrhythmia pathway is outside His-PK system - depolarisation takes longer
How is acute ventricular tachycardia treated (3)
stable: pharmacological cardioversion with anti-arrhythmic drugs
Unstable: direct current cardioversion (DCCV)
Correct triggers
What is involved in long-term treatment of ventricular tachycardia (2)
Implantable cardiovertor defibrillator (if life threatening, high risk of recurrence)
Ventricular tachycardia ablation
What are triggers of ventricular tachycardia (4)
electrolytes
Ischaemia
Hypoxia
Pro-arrhythmic drugs
Describe ventricular fibrillation (2)
Fast and irregular contractions
Heart loses ability to function as a pump
Describe heart block (bradycardia)
delayed/no conduction via atrioventricular node
What are the degrees of heart block
first - slow conduction
Second - intermittent conduction
Third - non-conduction
How does first degree heart block show up on an ECG
Long PR interval
How does second degree heart block show up on an ECG
varied PR interval
How + when is sinus bradycardia treated
atropine
Pacer
If symptomatic or unstable
What are clinical causes of arrhythmias (6)
Abnormal anatomy
Autonomic nervous system
Metabolic
Inflammation
Drugs
Genetics
How can abnormal anatomy cause arrhythmia (2)
congenital heart disease
Accessory pathways
What are example metabolic causes of arrhythmias (3)
hypoxia
Ischaemic myocardium
Electrolyte imbalances
How can genetics link to arrhythmias
Mutations can occur in genes that encode cardiac ion channels
What are the mechanisms of arrhythmias (2)
ectopic beats
Re-entry
What are ectopic beats (3)
beats/rhythms originating in places other than the sino-atrial node
Triggered activity
Altered automaticity
What does re-entry require (2)
multiple connected conduction pathways with different speeds of induction/recovery of excitability
Central blocking by a core block of issue so impulse can loop around via surrounding excitable tissue
When does re-entry occur
When an action potential fails to extinguish itself and re-activates a region that has recovered from refractoriness
What are substrates
electrophysiological abnormalities that pre-dispose to re-entry
What does arrhythmia propagation require (2)
triggers
Substrates
What are the symptoms of arrhythmias (7)
palpitations
Dyspnoea
Pre-syncope
Syncope
Angina
Heart failure
Anxiety
What investigations are performed form arrhythmias (5)
ECG/ 24hr ECG/ stress ECG
Bloods (FBC< biochemistry, thyroid function)
CXR
Event recorder
Echocardiography
What is CXR used to assess (2)
heart size and heart failure
What feature on an ECG shows abnormal repolarisation
a long QT interval
What can echocardiography be used to identify
structural heart disease
What is radiofrequency ablation
Selective localised cautery of cardiac tissue to prevent tachycardia
What can radiofrequency ablation target (2)
autonomic focus
Part of a re-entry circuit
What can radiofrequency ablation be used to do (2)
restore rhythm
Control rate
What is ablated to maintain sinus rhythm
Atrial fibrillation focus
What is ablated to control rate
Atrioventricular node
Prevents rapid conduction to ventricles
What are the four types of anti-arrhythmic drugs
reducing Na channel current
Beta blockers
Prolonging action potentials
Calcium channel blockers
Which drugs reduce sodium channels current (3)
lignocaine
Quinidine
Flecainide
Which drug is a beta blockers and anti-arrhythmic
propranolol
Which drugs prolong action potentials (3)
amiodarone
Sotalol
Dronedarone
Which drugs are calcium channel blockers (2)
verapamil
Diltiazem
What are the types of pacemakers (2)
single chamber (pace either right atrium or ventricle)
Dual chamber (pace both right atrium and ventricle)
Describe electrophysiological studies (2)
trigger clinical arrhythmias to study mechanisms
Radiofrequency ablation to extra pathway can be delivered
What is heart failure (2)
the state in which the heart is unable to pump blood at an adequate rate to meet the requirements of tissue/is only able to do so at high pressures
Due to impaired filling or ejection
What is ejection fraction and what should it be in a health individual
the percentage of blood pumped out of the heart during each beat
50%
What are the two types of heart failure
HRrEF - heart failure with reduced (40%) ejection function
HRpEF - heart failure with preserved ejection fraction
What is the impairment associated with HRrEF
Left ventricle is unable to eject enough blood during systole
What is the impairment associated with HRpEF
Less blood is able to fill the ventricle during diastole due to myocardial stiffness
What are the symptoms of heart failure (6)
SOB
Difficulty breathing at night
Reduced exercise tolerance
Fatigue
Tiredness
Ankle swelling
What investigations/examinations are used to diagnose heart failure (6)
neck exam
Auscultation of lungs and heart
Checking for oedema
ECG
Chest C-ray
Echocardiography
What lifestyle medications can be made to manage heart failure (4)
reduced water and salt intake
Regular exercise
Updated vaccinations
Mental health management
What pharmacological treatment can be used to prolong survival in the event of heart failure (6)
RAS inhibition (ACEi, ARII antagonists)
Beta blockers
Aldosterone antagonists
vasodilators
Sinus node blockers
SGLT2 inhibitors
What drugs can be used to improve symptoms of heart failure (2)
digoxin
Frusemide
What are the four pillars of therapy in heart failure
ARNII
Beta blockers
MRA - aldosterone receptor antagonists
SGLT2 inhibitors
What management is used for patients with refractor end-stage heart failure (3)
control of fluid retention
IV inotropics/vasodilators
Consideration of resynchronisation, mechanical assist devices, or heart transplant
What is cardiac resynchronisation therapy (2)
a method to manage left bundle branch block in heart failure
Pacing of left ventricle form left lateral wall to increase synchronous contraction and improve left ventricle haemodynamics
What changes can alter direction and magnitude of fluid movement across capillary walls
Increased capillary hydrostatic pressure
Decreased capillary oncotic reassure
Increased capillary permeability
Decreased lymphatic drainage
what is oedema
accumulation of fluid in interstitial spaces
what are the types of oedema (2)
pulmonary
Peripheral
how is oedema managed
with diuretics
What is the most common mechanism resulting in heart failure in patients with myocarditis
Systolic dysfunction
Which cells migrate from the tunica media into the tunica intima forming a fibrous capsule over a plaque
smooth muscle cells
