Arrhythmia Flashcards
(103 cards)
Reverse use dependence
Increased effect at slow heart rates All class III drugs including dofetilide
III: block outward potassium channel activity (IKs) and prolong refractoriness
Dofetilide side effects
Hypomagnesemia, hypokalemia, QT prolongation
Pacemaker cardiomyopathy
12% of patients who are paced >20% of the time-> change or upgrade to biventricular
Ventricular pacing alone (without atrial pacing) increases
Afib
Management of LQTS
Genetic testing of index patient Beta blockers ICDs if strong personal risk factors for SCD QTC > 480ms more definitive Polymorphic VT
Persistent afib
Paroxysmal
Long-standing persistent
Permanent
> 7 days
<7 days
12 months
We have stopped attempts to control and accepted it
Primary prevention ICD (MADIT-II trial)
Just EF and GDMT?
CRT (biventricular ICD) indication
EF <35%, QRS> 150, LBBB, sinus rhythm, class II-IV despite GDMT
Palpitations work up
24 hour holter vs event monitor
If risk factors for cardiac disease, attempt to correlate with monitor
Event monitor generally shown to be better
Palpitations and lightheaded ness with exercise and emotion in young person, positive family history
CPVT
Ryanodine receptor mutation more common
Transforming growth factor-beta (TGF-β) mutations
Familial thoracic aortic aneurysms
Fibrillin mutation
Marfan
Myosin heavy chain mutation
HCOM and dilated cardiomyopathy
Plakophilin mutation
ARVC
Monomorphiv VT that originates in RVOT
Differential
LBBB morphology (down in V1) with inferior axis, can ablate / BB/ CCB/ class 1C
idiopathic VT and arrhythmogenic right ventricular cardiomyopathy (ARVC)
RVOT VT is usually not ischemia driven
ARVC
Epsilon wave after QRS and TWIs in V1-V3
Get CT/MRI
Arrhythmias in Brugada
Beta blockers CI- increase ST elevation
Amiodarone is pro arrhythmic
Treat fever, avoid drugs and alcohol
Quinidine for
ICD w/ multiple shocks for VT
ICD is CI
LVOT VT
LBBB, inferior axis, early R wave progression
VT in structurally normal heart
VT in abnormal heart
Meds or ablate
ICD
Most common cause of VT (wise complex, positive concordance, monophasic R in V1) in CAD
Scar-mediated, re-entrant
Torsades in LQTS mechanism
Early afterdepolarizations
Mobitz type II vs complete heart block
Fixed PR interval
Brugada
Sodium channel blockers (flecainide, propafenone) can exacerbate the transient ECG abnormalities that occur in patients with Brugada syndrome who commonly have normal ECGs.