Cardiology Flashcards
What is the difference between a true and false aneurysm?
True: involves all three layers of artery - intima, media, and adventitia
False: only involves a single layer of fibrous tissue
What is the screening program for AAA?
65+ men, abdominal ultrasound
What causes AAA?
- Same risk factors as arterial disease: HTN, smoking, diabetes
- Connective tissue disease: Marfan’s
How does connective tissue disease increase the risk of AAA?
Disruption of extracellular matrix - change in balance of collagen and elastin fibres
How is AAA managed?
If symptomatic, or between 5.5-6cm, surgical
If asymptomatic, monitor for growth
How is Laplace’s law relevant in AAA?
Increase in size correlates with increase in pressure
As size of aneurysm increases, greater likelihood of rupture.
Which part of the heart do leads V1-4 correspond to?
Anterior
Which artery do leads V1-4 correspond to?
Left anterior descending artery
Which part of the heart do leads II, III, and aVF correspond to?
Inferior
Which artery do leads II, III, and aVF correspond to?
Right coronary artery
Which part of the heart do leads I, V5, and V6 correspond to?
Lateral
Which artery do leads I, V5, and V6 correspond to?
Left circumflex
What is the initial treatment for ACS?
300mg aspirin
How does MONAT link to ACS?
Morphine only if in severe pain Oxygen only if sats <94% Nitrates with caution if hypotensive Aspirin 300mg Ticagrelor
How are nitrates administered in ACS?
Sublingually, or IV
How are STEMIs managed?
Asprin 300mg
If patient has presented within 12 hours, and PCI possible in 120 minutes, PCI
If more than 12 hours, but patient still has symptoms of ongoing MI, consider PCI
If PCI not possible in 120 minutes, fibrinolysis. If ECG changes still present >90 minutes after fibrinolysis, offer PCI
If a patient is a candidate for PCI, how would you anticoagulate prior to PCI?
Dual antiplatelet therapy with aspirin and prasugrel if the patient is not already on an anticoagulant
If a patient is a candidate for PCI, and is already on an oral anticoagulant, how would you anticoagulate prior to PCI?
Dual antiplatelet therapy with aspirin and clopidogrel
What drug therapy would you give for patients during a PCI procedure using radial access?
Unfractionated heparin + bailout glycoprotein IIb/IIIa inhibitor (GPI)
What drug therapy would you give for patients during a PCI procedure using femoral access?
Bivalirudin without glycoprotein inhibtiors
What drugs should be given to patients undergoing fibrinolysis?
Antithrombin drugs
When should an ECG be repeated following fibrinolysis?
60-90 minutes - if persisting myocardial ischaemia, consider PCI
How should NSTEMI/unstable angina be managed?
Aspirin 300mg and fondaparinux if no immediate PCI planned
What are the risk factors for ACS?
- Age
- Male
- Family history
- Smoking
- Obesity
- Hypertension
- Hypercholesterolaemia
- Diabetes
Describe in 5 steps the pathophysiology behind ACS.
- Initial endothelial dysfunction triggered by smoking, hypertension, hyperglycaemia
- Pro-inflammatory changes to endothelium - pro-oxidant state, proliferative, reduced NO bioavailability.
- Fatty infiltration of the subendothelial space by LDLs
- Monocytes migrate and differentiate into macrophages. Macrophages phagocytose LDLs and become foam cells. As macrophages die, this can propagate the inflammatory process.
- Smooth muscle proliferation and migration from the media into the intima results in formation of a fibrous capsule covering the fatty plaque.
which risk stratification scoring system is used for NSTEMI to decide whether coronary angiogram?
GRACE score
what are the risk factors for AAA?
- Age (screening in 65+)
- Male
- Diabetes
- Smoking
- HTN
- Connective tissue diseases e.g. Marfan’s
What is the screening program for AAA?
men aged 65 or more - ultrasound measurement of the aneurysm
when is CT offered for AAA?
when size reaches 5cm - CT CAP with a view to manage surgically
When is surgery offered for AAA?
5.5-6cm
what symptoms of AAA
central tearing abdo pain, radiating to back
pulsatile, expansile mass in abdomen
what is the management of AAA
EVAR - endovascular repair
what complication of AAA repair using EVAR?
endo-leak - blood still collects in the aneurysm
what is the pathophysiology of aortic dissection?
tear in the tunica intima causes blood to pool in the tunica media
how is aortic dissection classified?
Type A - ascending aorta - 67% cases
Type B - descending aorta
what are the RFs of aortic dissection
- HTN
- Connective tissue disorders - EDS, Marfan’s
- Trauma
- Bicuspid aortic valve
- Noonan’s/Turner’s syndrome
- Pregnancy
- Syphilis
- Cocaine
What are the symptoms of aortic dissection
Central sharp, tearing chest pain.
Upper back pain if type B
some overlap between site of pain
What are the signs of aortic dissection
- HTN
- pulse deficit - weakness in pulse, absent brachial/femoral/carotid pulse
- variation (>20mmHg) in systolic BP between two arms
- aortic regurgitation
What are the complications of aortic dissection?
- Aortic regurgitation
- False lumen puts pressure on subclavian and renal arteries - renal failure
- Paraplegia
- Cardiac tamponade
- Stroke
- Myocardial Infarction
what murmur might be heard with aortic dissection?
diastolic murmur
which branch of coronary arteries is usually affected by aortic dissection and how would this present on ECG
right coronary arteries - inferior ST elevation (II, III, aVF)
how is aortic dissection managed
Type A - surgical
Type B - medical, occasionally surgical repair, but labetalol to prevent further progression
what surgical procedure for type b aortic dissection?
thoracic endovascular aortic repair (TEVAR)
What are the shockable cardiac arrest rhythms?
VT
VF
what are the non-shockable cardiac arrest rhythms
PEA
Asystole
how is tachycardia treated in an unstable patient?
- 3 synchronised shocks
- consider amiodarone infusion
how is tachycardia classified in a stable patient?
narrow (QRS <0.12s) and broad complex (>012s)
what are the three narrow-complex tachycardias
- AF
- Atrial flutter
- SVT
Give an example of broad-complex tachycardias
Ventricular tachycardia
How is AF rate control achieved
Beta blocker or diltiazem
how is atrial flutter rate control achieved
beta blocker
how is rate control achieved in SVT
vagal manoeuvres
IV bolus 6mg adenosine (verapamil in asthmatics)
electrical cardioversion
give examples of vagal manoeuvres
valsalva
carotid sinus massage
how is ventricular tachy treated
amiodarone infusion
what is the pathophysiology of atrial flutter
re-entrant electrical signal from atria loops back on itself and overrides normal sinus rhythm.
This establishes an endless loop of stimulation - tachycardia
what are the risk factors for atrial flutter
- Previous MI
- Ischaemia
- HTN
- Fibrosis
- Valvular heart disease
- obstructive sleep apnoea
what signs symptoms of atrial flutter
palpitations, chest tightness, heart failure
what investigations for atrial flutter
ECG
Echo for valvular disease, HF
TSH levels for hyperthyroidism
how is atrial flutter treated
- if hypertension/hyperthyroidism, treat underlying cause
- beta blocker for rate control
- anticoagulate based on chadsvasc
- radiofrequency catheter ablation
explain the pathophys of supraventricular tachy
- Electrical signal re-enters atria from ventricles
- Signal travels to AVN, stimulating another ventricular contraction
- Causes a self-perpetuating electrical loop
- Results in a narrow complex tachycardia (QRS <0.12s)
what is paroxysmal SVT?
remits and recurrs in same patient over time
give three causes of svt
- AV node re-entry tachycardia (re-entry through the AVN)
- Atrioventricular re-entrant tachycardia - re-entry to ventricles through an accessory pathway (eg WPW syndrome)
- Atrial tachycardia - ectopic electrical activity generated in the atria, but not from the SAN
how is svt treated
- Vagal manoeuvres (valsalva, carotid massage)
- IV adenosine, verapamil in asthmatics
- electrical DC cardioversion
what is the long term management of patients with paroxysmal SVT
beta blockers, rate limiting CCB, amiodarone
radiofrequency catheter ablation
explain the pathophysiology of wolff-parkinson white
Congenital accessory pathway connecting atria and ventricles, leading to AVRT.
how does wpw present on ecg
- delta waves (slurred upstroke to qrs)
- broad qrs
- short pr
- associated with left-axis deviation
how does WPW affect axis-deviation
if accessory pathway is in right atrium, left-axis deviation
if accessory pathway is in left atrium, right-axis deviation
how is WPW treated
radiofrequency ablation
sotalol, amiodarone, flecainide
when would you avoid giving sotalol/beta blockers/antiarrhythmics in WPW
if concurrent AF or atrial fibrillation
what conditions are associated with WPW
- HOCM
- Ebstein’s anomaly
- Secundum ASD
- Thyrotoxicosis
- Mitral valve prolapse
what ECG abnormality causes torsades de pointes
long QT
which electrolyte abnormalities cause long QT
hypocalcaemia
hypomagnesemia
hypokalaemia
how does hypothermia affect QT interval
hypothermia prolongs QT interval
list 6 drug groups that commonly cause QT prolongation
- Erythromycin and macrolides
- Antiarrhythmics - sotalol, amiodarone, flecainide
- Tricyclic antidepressants (amitriptyline)
- Antipsychotics
- Chloroquine
- Citalopram
What is the management of torsades de pointes acutely
Treat underlying cause
IV mag sulf
defibrillation if VT occurs
what is the difference between normal VT and torsades de pointes
normal VT is monomorphic
Torsades is polymorphic ventricular tachycardia
what is the long term management of torsades
- Beta blockers, but not sotalol
2. Pacemaker or implantable defibrillator
what are ventricular ectopics
random electrical impulse originating from outside the atria
how do ventricular ectopics present on ecg
individual random broad QRS on a background of normal ECG
what is bigeminy
ventricular ectopics happen so frequently that there is one for every normal sinus beat
what is first degree heart block
Delayed conduction of atrial impulse through AVN. Despite this, every atrial impulse results in a ventricular contraction.
How does first degree heart block present on ECG
prolonged PR interval (>0.2s) - 5 small squares/1 big square
What is second degree heart block mobitz type 1?
progressively prolonging PR interval until a dropped QRS occurs and the cycle restarts
what is second degree heart block mobitz type 2?
PR interval constant, but some atrial impulses fail to conduct, therefore occasional dropped beats occur, with no QRS.
There is usually a set ratio of impulses conducted to those not conducted, e.g. 3:1
how do you calculate the ratio for mobitz type 2?
how many P waves for every QRS. so if three p waves for every qrs, ratio of 3:1
which mobitz is associated with risk of asystole?
mobitz type 2
what is third degree heart block
no relationship between P and QRS - highest risk of asystole
which heart blocks are at risk of asystole
mobitz 2, third degree (complete)
what treatment for heart blocks at risk of asystole
atropine 500mcg IV
how would heart block present?
syncope
heart failure
regular bradycardia
what long term treatment for heart block
permanent pacemaker
what class of drug is atropine and how does it work
anti-muscarinic - inhibits the parasympathetic nervous system
what side effects of atropine (anti-muscarinic)
pupil dilatation
dry eyes
constipation
urinary retention
what causes arterial ulcers
insufficient blood supply to the skin due to peripheral artery disease
where do arterial ulcers usually occur
distal - toes, dorsum of foot, heel
what do arterial ulcers look and feel like?
small, punched out, may be necrotic/gangrenous, pale due to reduced blood supply
painful
describe surrounding limb in arterial ulcers
cold, hairless, pulseless
what is abpi in arterial ulcers
low ABPI
how are arterial ulcers treated
surgical revascularisation
no beta blockers and no compression
how do venous ulcers present
shallow, wide area, poorly defined borders, haemosiderin staining
occur in gaiter area
more likely to bleed than arterial
less painful than arterial
how is pain relieved in venous ulcers
pain relieved by elevating the leg
this is the opposite to arterial ulcers, where pain is relieved by lowering the leg
how are venous ulcers treated
compression therapy, analgesia - avoid NSAIDs
what ABPI measurement indicates PAD?
ABPI is ratio of systolic in legs to systolic in arms. ratio <1 indicates
what swabs if suspecting infection in foot ulcers
charcoal swabs
what analgesics must be avoided in venous ulcers
nsaids - can worsen condition
what are the three classifications of peripheral artery disease
intermittent claudication
critical limb ischaemia
acute limb-threatening ischaemia
what are the the risk factors for peripheral artery disease?
same as atherosclerosis - age, FH, male, smoking, HTN, hyperlipidaemia, alcohol, hyperglycaemia, obesity, sedentary lifestyle
how does intermittent claudication present?
leg (particularly calves) cramps when walking
predictably occurs after a certain distance of walking
better at rest
how does acute limb ischaemia present (6Ps)
Trophic changes - shiny, hairless shins
- Pain
- Pallour
- Pulseless
- Paraesthesia
- Paralysis
- Perishing cold
What sort of pain in critical limb ischaemia, and what symptoms?
Pain at rest
Ulceration
Gangrene
Burning pain, worse at night in bed with legs raised when gravity no longer helps to pull blood into lower limbs.
Pain better when dangling legs off bed
what assessments would you do for someone with intermittent claudication
- assess for pulses:
femoral, popliteal, posterior tibialis, dorsalis pedis - ABPI measurement
- FIRST LINE INVESTIGATION: duplex ultrasound
- MR angiography prior to any interventions
What is the first line investigation of intermittent claudication
duplex ultrasound
what ABPI value suggests critical limb ischaemia?
<0.6
what ABPI value suggests intermittent claudication
<0.9
what does a high ABPI (>1.3) indicate
calcification of arteries, making them difficult to compress
more common in diabetic patients
what is the management of intermittent claudication
- lifestyle changes - stop smoking, lose weight, exercise
- exercise training
- pharmacological: statin, clopidogrel, naftidrofuryl oxalate
- endovascular angioplasty + stenting
- endarterectomy
- bypass graft surgery
what is the management of critical limb ischaemia
Urgent referral to vascular team for revascularisation
- endovascular angioplasty + stenting
- endarterectomy
- bypass graft surgery
- limb amputation if irreversible ischaemia
what is the management of acute limb-threatening ischaemia
urgent referral to on-call vascular team
- endovascular thrombolysis
- endovascular thrombectomy
- surgical thrombectomy
- endovascular angioplasty
- endarterectomy
- bypass graft surgery
- limb amputation if irreversible ischaemia
what are the two causes of acute limb threatening ischaemia. explain the pathophys of each
thrombus: rupture of atherosclerotic plaque in previously atherosclerotic peripheral artery
embolus: originating from elsewhere eg AF
what factors would suggest thrombus causing acute limb ischaemia
- pre-existing claudication with sudden deterioration
- no obvious source for emboli (AF, recent MI)
- reduced/absent pulses in contralateral limb
- evidence of widespread vascular disease (MI, stroke, TIA, previous vascular surgery)
what factors would suggest embolus causing acute limb ischaemia
- sudden onset painful leg
- no pre-existing claudication/PAD
- present pulses in contralateral limb
- source of embolus identified - AF, recent MI
- evidence of proximal aneurysm - abdominal/popliteal
what analgesic for acute limb ischaemia pain
IV opiates
what pharmacological management for PAD
statin - atorvastatin 80
clopidogrel
naftidrofuryl oxalate - vasodilator
what causes leriche syndrome
occlusion of distal aorta or proximal common iliac artery
what is leriche syndrome triad
- buttock/thigh claudication
- absent femoral pulse
- male impotence
what is aortic stenosis caused by
- degenerative calcification
- bicuspid aortic valve
- william’s syndrome - postvalvular aortic stenosis
- post-rheumatic disease
- subvalvular: HOCM
what are the symptoms of aortic stenosis
chest pain
dyspnoea
syncope/presyncope (exertional dizziness)
murmur - Ejection systolic murmur
what are the signs of aortic stenosis
narrow pulse pressure absent S2 slow rising pulse thrill S4 heart sound?