Cardio Flashcards
What ECG changes are associated with hyperkalaemia?
peaked or ‘tall-tented’ T waves (occurs first)
loss of P waves
broad QRS complexes
sinusoidal wave pattern
What are Stokes Adams attacks?
A sudden loss of consciousness, usually without warning and lasting for a few seconds, due to an abnormal heart rhythm (especially complete atrioventricular block).
What causes cannon A waves?
occur in conditions with atrioventricular dissociation and right atrial contraction against a closed tricuspid valve
How does pericarditis usually present?
- pleuritic chest pain (sharp retrosternal pain caused by inflammation of te parietal pleura, aggravated by swallowing , coughing or deep inspiration)
- pain improves on sitting and leaning forward
- low grade intermittent fever
- non-productive cough
What investigation findings are seen in pericarditis?
ECG changes: diffuse ST elevations and PR segment depression; T-wave inversion
Echo: effusion may be present, often normal
CXR: usually normal
WCC: leukocytosis
Management of acute pericarditis
often self-limiting
NSAID (with gsastroprotection)
can consider colchicine
consider prednisone
surgical management is pericariectomy
What is Dressler syndrome
post-myocardial infarction syndrome
occurring 2-10 weeks post MI without an infective cause
(thought to be due to circulating antibodies against cardiac muscle cells -> autoimmune aetiology -> immune complex deposition -> inflammation)
Differences in the shape of ST elevation in pericarditis and MI
concave upwards ST elevation is associated with pericarditis
convexity in ST elevation is seen in MI
What viruses commonly cause pericarditis?
Coxsackie B virus group
What bacteria can cause pericarditis?
is bacterial or viral more common
viral is more common (Coxsackie B)
Bacterial may be due to staphylococcus spp., streptococcus spp., M tuberculosis
What is Eisenmenger’s syndrome
reversal of a left-to-right shunt (associated with VSDs, ASD and a PDA)
Classification systems for aortic dissection
Stanford (type A and B)
DeBakey (I, II, III)
What is the anticoagulation of choice in patients with AF?
DOAC
- apixaban
- dagibatran
- edoxaban
- rivaroxaban
Warfarin is second line (where DOAC is contraindicated or not tolerated)
List the reversible causes of cardiac arrest
The 4 Hs and 4 Ts
Hypoxia
Hypovolaemia
Hyperkalaemia, hypokalaemia, hypoglycaemia, hypocalcaemia, acidaemia and other metabolic disorders
Hypothermia
(+heroin +hypoglycaemia)
Thrombosis (coronary or pulmonary)
Tension pneumothorax
Tamponade - cardiac
Toxins
Acute management of heart block
-IV loop diuretics (furosemide, bumetanide)
+/- oxygen (aim 94-98%)
+/- vasodilators (nitrates; main contraindication/SE is hypotension)
+/- CPAP if resp failure
in patients with hypotension:
- inotropic agents e.g. dobutamine
- vasopressors (e.g. norepinephrine)
- mechanical circulatory assistance (e.g. intra-aortic balloon counterpulsation or ventricular assist devices)
may need to stop b-blockers if:
- >50 bpm
- 2nd/3rd degree AV block
- shock
What type/location of MI most commonly predisposes you to AV block?
Inferior
What system is used in the classification of chronic heart failure?
NYHA classification
new york heart association classification
Duration of management of an unprovoked PE
6 months (DOAC e.g. rivaroxaban)
inheritance pattern of HOCM
AD
what classifications are used for aortic dissection?
Stanford
(A and B)
DeBakey (I, II, IIIa, IIIb)
-> emergency surgery is needed in Stanford A and DeBakey I and II.
A(S) and I and II (D) affecting the ascending aorta.
Signs and sx of aortic dissection
- sudden onset, severe pain, radiating to the chest/abdomen/back
- tearing/ripping pain
- anterior chest (ascending) or back (descending)
- interscapular or retrosternal pain
- asymmetrical BP and pulse readings on both sides
- syncope
- diaphoresis
- confusion
Definition of aortic dissection
- tear in the inner layer of the aorta that leads to a progressively growing hematoma in the intima-media space.
RFs for aortic dissection
- HTN
- age
- smoking
- people with connective tissue diseases may be affected at a younger age (30-50) as opposed to 60-80
Investigations for ?aortic dissection
- obs (incl. bilateral pulse and BP)
- ECG
- CXR (often normal but can have widened mediastinum)
- CT angio (may see double lumen) - in stable patients
- MRA
- Transoesophageal Echo (in unstable patients or in renal insufficiency/contrast allergy)
Management of aortic dissection
If Stanford A / DeBakey I or II -> IMMEDIATE SURGERY
- open surgery
- endovascular treatment (only in type B dissections and if the open operative risk is too high)
Otherwise treat conservatively, unless complications occur.
Medical Therapy:
- if hypotensive: aim MAP 70 or euvolaemia with IV fluids +/- vasopressor support; AVOID INOTROPES as they can worsen aortic wall stress
- Hypertensive: BP control! srart with IV beta blocker followed by vasodlator)
- supportive care: pain management (morphine)
complications of aortic dissection
- aortic rupture, acute blood loss, shock -> EMERGENCY SURGERY
Type A complications
- MI
- aortic regurg
- cardiac tamponade progressing to cardiogenic shock
- stroke
Complications of type A and type B
- arterial occlusion followed by ischemia of the
-> renal arteries -> AKI
-> spinal arteries -> weakness of the lower extremities due to paraplegia
What can you see on CTA/MRA in aortic dissection?
double lumen
Beck’s triad of cardiac tamponade
Hypotension
Muffled heart sounds
Raised JVP
what are the pros and cons of bioprosthetic and mechanical heart valves?
bioprosthetic
- higher failure rate (structural deterioration and calcification)
+ don’t usually require anticoagulation (if needed, they get warfarin for 3 months and then long term low dose aspirin)
mechanic
+ low failure rate
- increased risk of thrombosis -> require long-term anticoagulation with warfarin
Where do bioprosthetic heart valves commonly come from?
porcine and bovine
target INR for aortic and mitral valves in mechanical valve replacement
aortic: 3.0
mitral: 3.5
What is the most common cause of death in patients following a myocardial infarction?
ventricular fibrillation
During what part of the cardiac cycle is the heart perfused?
diastole
(during systole the blood is sent to the rest of the body)
Law of flow in relation to radius
Poiseuille’s Law
flow is proportional to r^4
(halving radius would decrease the flow 16x)
main features of angina
- central (crushing) pain / constricting discomfort in the front of the chest or in neck, shoulder or arm
- precipitated by physical exertion
- relieved by rest or nitrates within 5 minutes
Ix in people with stable angina to assess risk
- bloods: fasting glucose, HbA1c, lipid profile, thyroid function
- resting and ambulatory ECG
- resting Echo
-> higher risk and worse sx flavour functional testing +/- invasive angiography
MoA of dobutamine
beta 1 agonist
(enhances cardiac contractility etc.)
how is a stress echo done?
it is a functional test
after exercise or giving someone dobutamine before (beta 1 agonist)
what is the first line Mx of stable angina?
non-dihydropyridine CCB e.g. dilitazem
or BB
What should all patients with stable angina be prescribed?
aspirin with PPI
statin
GTN
BB or non-DHP CCB
2nd line meds for stable angina?
long acting nitrates
ivabradine
ranolazine
nicorandil
name of syndrome of pericarditis following MI
Dressler syndrome
Causes of pericarditis
infection (viral e.g. coxsackie, TB)
malignancy
connective tissue (RA, SLE)
Dressler’s syndrome
uraemia
Mx of pericarditis
1st line: NSAIDs + colchicine
2ns: add steroids
3rd: azathioprine
Where on the leg would you find a scar from a CABG procedure?
saphenous vein runs medially, therefore the scar for a CABG would be on the medial aspect of the leg/calf
Keep in mind thata now often the LIMA is used for CABG.
indication for a CABG
multi vessel CAD
angina not responding to optimal medical management
CABG - where can you get the graft from?
arterial graft harvesting in the arm
venous graft harvesting from the leg
What do you want to know in someone who had an MI?
What happened when the MI occurred?
What were the consequences of the MI
How is the MI being treated
Wellen syndrome
critical stenosis of LAD
-> high risk of anterior wall MI within the next days/weeks
pts pain might have resolved at the time of presentation and cardiac enzymes may be normal or minimally elevated
-> management: admission and coronary intervention
ECG findings in Wellen syndrome
- biphasic or deep T wave inversion in V2-V3
- minimal ST elevation
- no Q waves
SA & AV nodes - what do they do?
SA node: impulse initiation issues
AV node: impulse propagation
commonest cause of ventricular arrythmia
ischaemic heart disease
commonest cause of SA node dysfunction
age
sick sinus syndrome
Sinus node dysfunction
= an abnormality in sinus node acrion potential generationor conduction
causes:
- intrinstic (SA node fibrosis/degeneration/ischaemia
- extrinsic (hypothyroidism, negative chronotropes)
pts present with signs and symtpoms of end-organ hypoperfusion due to bradycardia (fatigue, dyspnoea, SOBOE), +/- Stokes Adams attacks
tachycardia bradycardia syndrome is a subtype of SND with an increased risk of cardiovascular events and mortality
Dx: ECG and stress test
what is a junctional rhythm?
rhythm coming from the AV node or below
this will be at a lower rate
What is a 3rd-degree heart block?
completeheart block
no conduction between atria and ventricles
P waves and QRS have thor own rhythms but bear no relationship to each other
Management of a symptomatic 2nd degree type 2 heart block?
follow the adult bradycardia algorithm
you are worried about 2nd degree type 2 ad a type 3 AV block - they are dangerous rhythms
- high risk of systole (if it occurs with with end organ dysfunction e.g. syncope, a pacemaker is likely needed)
indication for insertion of a pacemaker in heart block
end-organ dysfunction
AVNRT management
unstable -> synchronised shock
stable ->
why synchronised shock in AVNRT?
the point of synchronisation is for it to occur on the R
where is the defect in atrial fibrillation?
pulmonary veins
bulk of the impulse formation in AF is in pulmonary veins
they take over
in advanced AF the pulmonary veins are ablated
how does flecainide work
blocks sodium channels (Ic)
classification of anti-arrhythmic drugs
Vaughan Williams
mx of a >48 h of AF
anticoagulation (based on CHADSVASC and ORBIT score)
Rate/ rhythm control
LAA
left atrial appendage
AF predisposes towards LAA thrombus formation which may result in embolic stroke
CO formula
HR x SV
bumetanide MoA
loop diuretic
dapaglifozin MoA
SGLT2i
inhibits proximal sodium and glucose reabsorption
-> glycosuric and natriuretic agent
Which medications do you give in HF?
ACE inhibitor
BB
then
MC receptor antagonist
then
dapaglifozin
any congestion -> diuretics
NYHA… -> Entresto
fluid restriction is not recommended by NICE
Why does CPAP work in heart failure?
alveoli collapse on themselves because of the water in them
CPAP forces air in the alveoli
CPAP also increases intrathoracic pressure which decreases venous return
management of acute heart failure
loop diuretics (ideally continuous) with output monitoring
CPAP if acute pulm oedema and dyspnea
hemofiltration only if
Don’t give morphine
Don’t give beta blockers
nitrates show no improvement in mortality (they don’t cause harm, only advised by NICE in severe HTN/evidence of myocardial iscemia)
C
What does PCI stand for?
percutaneous coronary intervention
What are the valves of the heart and how to remember them?
RTP
(RA -> tricuspid -> pulmonary artery)
LMA
(LA -> mitral/bicuspid -> aorta)
List the layers of the heart from innermost to outermost
endocardium (1 cell thick)
myocardium
visceral pericardium
parietal pericardium
fibrous pericardium
What are the main coronary vessels?
RCA (right coronary artery)
LCx (left circumflex)
LAD (left anterior descending)
where is the coronary sinus and where does it drain?
sinus itself is situated within the atrioventricular groove on the posterior surface of the heart between the left atrium and ventricle.
drains blood from coronary veins into the right atrium via the coronary sinus orfice
Summarise the Frank Sterling relationship
filling of the heart increases the force of contraction
increased diastolic fibre length increases ventricular contraction
ventricles pump greater SV so that, at equilibrium, CO exactly balances the augmented venous return
What is the law of LaPlace?
when the pressure within a cylinder is held constant, the tension on its walk increases with increasing radius (T = P x R)
T = (PxR)/h -> when incorporating wall thickness
What are the molecular steps that occur during contraction of the heart?
- SA node depolatises
- AP travels down T-tubules
- Ca2+ enters cell
- Ca2+ binds to Ryanodine receptor (RyR)
- Ca2+ enters cytoplasm from sarcoplastic reticulum (calcium mediated calcium release)
- Ca2+ binds to troponin C (leads to conformational changes of troponin I tropomyosin -> opens cross bridge binding sites)
- Myosin heads bind to actin
- Muscle fibres shorten
- Sarcoplasmic endoreticular calcium pump brings Ca2+ back into the sarcoplasmic reticulum for relaxation
What medications can you use for rhythm control in AF?
beta blocker (bisoprolol is commonest)
CCB (has to be a rate limiting one, e.g. dilitazem)
b blocker in HF?
bisoprolol
xx
ca..olol
What patients would you not give a beta blocker to for rate control? what is the alternative?
asthma
can give CCB that rate controls, e.g. dilitazem
How will you assess stroke risk in AF?
Chadvasc
ORBIT score
valvular/non-valvular disease
DOAC vs warfarin
what is the ORBIT score for?
bleeding risk
what is the biggest risk of AF?
stroke
Does DOAC vs warfarin make a difference in valvular disease?
in valvular heart disease use warfarin, not DOAC
examples of DOACs
apixaban
rivaroxaban
etc
Cardioversion types
electrical (DC cardioversion)
pharmacological (e.g. flecainide, sotolol -> these can be CI’d in structural heart disease, then you would have to do electrica lcardioversion)