Cardiovascular Conditions: Arrythmias Flashcards
Arrhythmia is,,,
an abnormal heart rhythm, causing heart to beat too slow or too fast
Which node is the hearts pacemaker?
SA node
When is QTc considered prolonged?
> 440ms, but usually > 500ms is worrying
QT prolongation risk factors
Higher doses
Multiple QT prolonging drugs
Reduced drug clearance
Low potassium, mag, calcium
Other cardiac conditions
Female gender
Class I anti arrhythmic drugs mechanism
Na-channel blockers
Reduces speed of ion conduction through sodium channels
Class Ia, Ib, Ic
Double Quarter Pounder, Lettuce, Mayo, Fries, Please
Ia = DQP
Ib = LM
Ic = FP
D = disopyramide
Q = Quinidine
P = Procainamide
L = Lidocaine
M = Mexiletine
F = Flecainide
P = Propafenone
Class II anti arrhythmic drugs
Beta blockers
Class III anti arrhythmic drugs
K- channel blockers
D = Dronedarone
D = Dofetilide
S = Sotalol
I = Ibutilide
A = amiodarone
Class IV anti arrhythmic drugs
non-DHP CA blockers
Diltiazem
Verapamil
**Dont use in HF and HFrEF **
Paroxysmal AF
terminates spontaneously or with intervention within 7 days of onset
Persistent AF
continuous AF > 7 days
Long-standing Persistent AF
continuous AF > 12 months
Permanent AF
clinician/patient cease further attempt to restore/maintain normal sinus rhythm
Valvular AF
AF w/ moderate-severe mitral stenosis or with mech heart valve, long term warfarin anticoag indicated
Non-valvular AF
AF w/o moderate-severe mitral stenosis or mech heart valve
Rate control goals
resting HR < 80 BPM in symptomatic patients
resting HR < 110 BPM in asymptomatic w/ preserved left ventricular function
Preferred rate control treatment?
BB
non-DHP (dont use in HFrEF)
Rhythm control - Cardioaversion
High risk of thromboembolsim, zap the heart
pt should start anticoagulant 3 weeks before, and continue 4 weeks after
INR 2-3 if on warfarin
Rhythm control - pharmacologic cardio aversion
amiodarone
dofetilide
flecainide
ibutilide
propafenone
Amiodarone Boxed warning
Pulmonary toxicity
Hepatotoxicity
Amiodarone Contraindications
Iodine hypersensitivity
Amiodarone Warnings
Hyper/Hypothyroidism (hypo is common)
optic neuropathy
photosensitivity (slate-blue skin discoloration)
Amiodarone Side effects
hypotension
bradycardia
corneal microdeposits
photosensitivity
Amiodarone monitoring
ECG
BP
HR
Electrolytes
LFTs Q 6 months
Thyroid function
Amiodarone 1/2 life
40 - 60 days
Common drug interactions amiodarone
digoxin = decrease digoxin by 50%
warfarin = decrease warfarin by 30-50%
no more than 20mg/day simvastatin
no more than 40mg/day lovastatin
Dont sue with sofosbuvir, can increase bradycardic effect
Digoxin contraindications
V. Fib
Digoxin monitoring
Digoxin lvls, 12-24hrs after dose
Digoxin toxicity
N/V
loss of appetite
blurred/double vision
greenish-yellow halos
bradycardia
life threatening arrhythmias
low potassium, mag, calcium inc risk of digoxin toxicity
Digoxin antidote
DigiFab
Disopyramide warnings and Side effects
Warnings: pro arrhythmic
SE: anticholinergic effects
Quinidine take with or without food?
With food or milk to decease stomach upset
Quinidine warnings and Side Effects
Warnings: Proarrhythic, hemolysis risk (dont use in G6PD deficiency), can cause positive Coombs test
SE: DILE, diarrhea, stomach ache
Cinchonism (Quinidine OD) = tinnitus, hearing loss, blurred vision, headache, delirium
Procainamide boxed warnings
potentially fatal agranulocytosis
monitor first 3 months
long-term use leads to + ANA in 50% pts, can result in DILE (20-30% pts)
Procainamide Slow acetlyators
at risk for drug accumulation and toxicity
fast acetylators can have subthereapeutic drug conc
Drug used for refractory VT and cardiac arrest?
Lidocaine injection
Propafenone Side effects
metallic taste
Dronedarone Boxed warnings
inc risk of death/stroke in HF pts or permanent AF
Dronedarone CI
concurrent use strong CYP3A4 inhib and QT prolonging drugs
Dronedarone warnings
Hepatic failure (esp first 6 months)
pulmonary disease
Dronedarone SE
QT prolongation
diarrhea
Sotalol dosing adjustments
CrCL < 60 = decrease frequency
CrCl < 40 = depends on formulation
Ibutilide notes
correct hypokalemia and hypomagnesemia before use and throughout treatment with medication
Dofetilide boxed warning
initiated in setting of continuous ECG monitoring, assess CrCl for min 3 days, QT prolongation
Dofetilide CrCl adjustments
CrCl < 60 = decrease dose
CrCl < 20 = contraindicated
Dofetilide is the anti arrhythmic drug of choice in
Heart failure
