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12.11.21 Cardiac

Heart failure basics
  • Definition
    • Inability of the heart to provide oxygen requirements of tissue
    • Or only at the expense of raised LV filling pressure
  • Causes
    • 50% CAD
    • Idiopathic 25%
    • Valve disease 10%
    • HTN 4%
    • Alcohol 4%
  • Survival varies depending on aetiology
    • But pooled 5-year survival is <50%
  • Signs
    • Raised JVP
    • Hepatojugular reflex
    • 3rd heart sound
    • Displaced apical impulse
    • Murmur
  • CXR
    • A - Alveolar oedema
    • B - B lines
    • C - Cardiomegaly
    • D - Diversion to upper lobe
    • E - Effusion
  • BNP
    • False positive if old, female, AF, LVH, renal or resp failure, PE ...
  • Drugs with survival benefit
    • ACE inhibitor
    • Beta blocker
    • Spironolactone
  • Calcium channel blockers in heart failure
    • NOT diltiazem or verapamil as they decrease contractility
    • Dihydropyridines (e.g. nifedipine) are OK as they have peripheral action
  • Pacing
    • Can help heart failure
    • DON'T put pacing leads, or anything else, in the left heart!
      • cf thrombosis
    • If you need LV pacing, thread it round the veins, on the outside

Angina
  • Definition
    • Chest pain described as constriction/discomfort in chest, +/- radiation
    • Brought on by exercise or emotion
    • Relieved by rest or GTN
  • Not all 3?
    • Only 2 out of 3 = Atypical angina pain
    • 0 or 1 out of 3 = Non-anginal pain
  • Most common cause
    • Atherosclerotic narrowing of coronary arteries
    • Symptomatic if >70%
  • Risk factors
    • Fixed
      • Age
      • Male
      • Genetics
    • Modifiable
      • Tobacco
      • HTN
      • DM
      • Hypercholesterolaemia
      • Depression
      • Obesity
  • Treatment options
    • Lifestyle modification
    • Pharmacotherapy
    • PCI
    • Surgical revascularisation
  • ECG features
    • T wave inversion
    • ST depression
    • LVH
    • LBBB
  • Exercise stress test
    • Very poor specificity
    • Therefore only useful when PPV is high
      • i.e. Previous Hx of CVD
  • Investigation based on risk
    • <10% => Consider non-cardiac cause
    • 10-30% => Do CT calcium score
    • 30-60% => Do functional test
      • Myoperfusion scan
      • Dobutamine stress echo
      • Stress MRI
    • 60-90% => Straight to coronary angiogram
  • CT calcium score interpretation
    • 0 => Consider other causes
    • 1-400 => 64-slice CT coronary angiography
    • >400 => Invasive angiography as you won't see shit on a CT angiogram
  • Treatment
    • Symptoms
      • Start with a beta blocker
      • Add a CCB if still symptomatic
        • Use a non-dihydropyridine (diltiazem, verapamil)
          • Block the AV node and slow rate
      • Then add ranolazine if still symptomatic
        • Sodium channel blocker
      • Plus PRN GTN
    • Secondary prevention
      • B - Beta blocker
      • A - Aspirin
      • S - Statin
      • I - ACEi
      • C - Control risk factors
  • Checkups
    • Glucose
    • Lipids
    • Hb
    • TFTs
    • U+Es
  • Indications for surgery over PCI
    • Disabled
    • > 65
    • Complex 3-vessel disease
    • Left main stem disease

ACS
  • Subtypes
    • STEMI
    • NSTEMI
    • Unstable angina
  • The 11 Ps
    • Pain relief
      • Morphine + cyclizine
    • Paralyse the platelets
      • Aspirin, clopidogrel, LMWH
    • Pacify the plaque
      • High-dose statin
    • Perfuse the myocardium
      • PCI
    • Prevent adverse remodelling
      • ACEi, Beta blocker
    • Predict risk of sudden death
      • GRACE, Echo
    • Protect from sudden death
      • Aldosterone receptor antagonist (eplerenone)
        • NB less anti-androgen effects than spironolactone
    • Promote exercise
    • Prevent smoking
    • Praise health
    • Permit sex after 2 weeks
  • Other things causing a trop rise
    • Myocarditis
    • Tachyarrhythmia
    • DC cardioversion
    • Sepsis
    • Trauma
    • CPR
    • Renal failure
    • Cardiomyopathy
    • PE

Arrhythmias
  • Types and causes
    • Brady
      • Sinoatrial node disease
      • Conduction disease
    • Tachy
      • AF/flutter
      • SVT
        • AVNRT
        • AVRT
        • Atrial tachyarrhythmia
      • VT
      • VF
  • Sinus node disease - subtypes
    • Slow rate
    • Occasional failure
    • Exit failure
    • Tachy-Brady syndrome
  • LBBB
    • Supraventricular origin
    • QRS ≥ 120 ms
    • QS or rS complex in V1
    • RsR' wave in V6
  • Wenkiebach
    • Progressively longer PR, then dropped beat
  • Mobitz II
    • Regular dropped beats
  • Escape
    • Infranodal
      • Broad QRS, as not using normal pathway
    • High junctional
      • Uses His-Purkinje system => Narrow QRS
  • Junctional bradycardia
    • Retrograde P waves
    • Weird STs
    • May see in a paced rhythm
  • AF
    • May be coarse or fine
    • Often originates in areas round the pulmonary vein
    • Bigger heart => Predisposition to AF
      • And AF => Bigger heart, so AF BEGETS AF
  • Atrial flutter
    • Dependent on a SLOW ZONE for re-entry round the circuit
      • So can fix by ablation of this zone
    • Conduction through the AV node may be regular or variable
  • Atrial tachycardia
    • Due to enhanced automaticity
    • With AV block, can look like flutter
  • AVNRT
    • Suspect AVNRT if there's an unexplained tachycardia
    • Dependent on the slow and fast pathways through the AV node
      • Can set up a self-propagating loop
      • This then spreads out to the ventricles and sometimes to the atria too
        • => Retrograde P waves
    • P waves may be buried in other stuff, making it all look weird
  • AVRT
    • Orthodromic 
      • Normal pathway carries impulse to ventricles
        • Uses bundle of His => Narrow QRS complexes
      • Impulse retrogradely re-enters the atrium via the accessory pathway
        • P waves follow QRS complexes
    • Antidromic
      • Accessory pathway carries impulse down into ventricles
        • Outside of the bundle of His => Wide QRS, maybe with delta wave
      • Impulse re-enters the atrium retrogradely via the AV node
    • Pathway: Posterioseptal or right-sided
  • Pre-excitation
    • WPW 
    • Delta waves
  • VT
    • Types
      • Polymorphic
      • Monomorphic
    • Check the axis to see if it could be coming from the AV node
    • Broad-complex tachycardia is VT until proven otherwise

Notes
  • ACS stats
    • 40% of A&E admission are for chest pain
    • 40% of STEMIs die within minutes
  • LBBB causes
    • Underlying CVD
    • Underlying heart muscle disorder
    • Congenital conduction disorder
    • Calcific aortic stenosis
  • Key drugs for management of angina: BETA BLOCKER AND CALCIUM CHANNEL BLOCKER
  • Normal sinus rhythm vs Atrial premature depolarisations vs SVT
  • Epsilon wave 
    • Small positive deflection (‘blip’) buried in the end of the QRS complex
    • Characteristic finding in arrhythmogenic right ventricular dysplasia (ARVD)

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