Arrhythmias Flashcards
conduct
transmit electrical charges
cardiac conductive system
electrical signalizing system that causes the atria and ventricles to contract
auscultation
listening to heart with stethoscope
arrhythmia
abnormal heart rhythm
can result in bradycardia (slow) or tachycardia (fast)zz
symptoms of arrythmia
heart “fluttering” or “skipping a beat”
dizziness
SOB
fatigue
diagnosis of arrhythmia
`ECG
Holter monitor
ambulatory ECG
detects intermittent arrythmias
normal sinus rhythm (NSR)
starts at SA node = pacemaker
60-100 BPM
conduction pathway
SA node
R and L atrium
AV node
Bundle of His
R bundle branch and R ventricle
L bundle branch and L ventricle
Purkinje fibers
source of arrhythmias
SA node firing abnormal rate/rhythm
scar tissue from past heart attack blocks/diverts signals
another part of the heart is acting as pacemaker
action potential
movement of ions through channels in myocytes that cause electrical impulses in the cardiac conduction pathway
give electricity to power heart
SA
pacemaker that has automaticity in cells = initiate own action potentials
Phase 0
heartbeat initiated
rapid ventricular depolarization = influx of Na = ventricular contraction
QRS complex
Phase 2
plateau response to influx of Ca and efflux of K
Phase 3
rapid ventricular repolarization bc efflux of K = ventricular relaxation
T wave
most common cause of arrhythmias
myocardial ischemia or infarction
non-cardiac conditions that can cause arrhythmias
electrolyte imbalances - K, Mg, Na, Ca
high sympathetic state - hyperthyroidism, infection, drugs (illicit drugs, antiarrhythmics, drugs that inc QT
origins of arrhythmias
supraventricular (above AV node)
ventricular (below AV node)
most common type of arrhythmia
atrial fibrillation
irregular/usually rapid ventricular response
inc risk of clot = stroke risk = may need anticoagulation
ventricular arrhythmias
premature ventricular contractions = skipped heartbeat; related to stress or too much caffeine
if in series = HR >100 = ventricular tachycardia
untreated VT can degenerate into ventricular fibrillation = completely disorganized electrical activation of ventricles = medical emergency
prolongation of QT interval
risk for Tosade de Pointes = can cause sudden cardiac death
QT prolongation risk factors
high dose of drug
multiple drugs
reduced drug clearance (drug interaction)
electrolytes: hypokalemia, hypomagnesemia
other cardiac conditions
drugs that inc or prolong QT interval
antiarrhythmics: !a, !c, III
hydroxychloroquine
azoles (except isavuconazaonium)
macrolies
quinolones
Lefamulin
SSRIs (worst w citalopram and escitalopram)
TCAs
mirtazapine
trazodone
venlafaxine
setrons
droperidol
metopclopramide
promethazine
First generation antipsychotics (haloperidol,
chlorpromazine, thioridazine)
Second generation antipsychotics (ziprasidone worst)
androgen deprivation therapy (leuprolide)
TKIs (nilotinib)
oxaliplatin
other: cilostazol, donepezil, fingolimod, hydrozyzine, loperamide, methadone, ranolazine, solifenacin, tacrolimus
what to do before starting drug from non-life-threatening arrythmia
check electrolytes/tox screen for reversible cause
Vaughan Williams classification
categorizes antiarrhymic drugs based on dominant electrophysiological effect
Double Quarter Pounds, Lettuce, Mayo, Fries Please
Because Dieting During Stress Is Always Very Difficult
Class I drugs
Na-channel blockers
proarrhythmic; caution with cardiac disease
Ia: disopyramide, quinidine, procainamide
Ib: lidocaine, mexiletine
Ic: flecainide, propafenone
Class II drugs
Beta-blockers
slow ventricular rates
Class III drugs
K-channel blockers
Dronedarone
Dofetilide
Sotalol
Ibutilide
Amiodarone
Class IV
Ca-channel blockers, non-DHP
verapamil
diltiazem
amiodarone and dofetilide preferable for AF in pts with HF
Sotalol
low ventricular rate
digoxin
Na-K-ATPase blocker
adenosine
activates adenosine receptors
used for paroxysmal supraventricular tachycardia
rate control goals
goal HR <80 BPM if symptomatic
lenient <110 BPM maybe if asymptomatic and have preserved L ventricular function
rate control meds
BB preferred
non-DHP CCB - do not give to HFrEF patients
rhythm control
convert to NSR and maintain NSR
cardioversion has high risk of thromboembolism; have anticoagulation at least 3 weeks before cardioversion and continue at least 4 weeks after cardioversion
NOACs preferred over warfarin in non-valvular AF
warfarin indicated in AF and mechanical heart valve
can cardiovert with Class Ia, Ic, or III antiarrhythmic drugs or electrical cardioversion (do not use drugs if permanent AF)
amiodarone BBW
pulmonary toxicity
hepatotoxicity
for life-threatening arrhythmias only
proarrhythmic, must be hospitalized for IV loading dose
amiodarone dosing
T1/2 = 40-60 days
amiodarone CI
iodine HSN
amiodarone warnings
hyper/hypothyroidism - amio inhibitors conversion of T4 to T3
optic neuropathy
photosensitivity (slate-blue skin discoloration)
amiodarone side effects
hypotension
bradycardia
cornealmicrodeposits
photosensitivity
amiodarone monitoring
ECG
BP
HR
electrolytes
LFTs
thyroid function
amiodarone notes
infusions >2 hrs need non-PVC container (polyolefin/glass)
premixed IV bags: Nexterone comes in non-PVC, non-DEHP container
antiarrhythmic DOC in HF
decrease infusion rate/dc prn for hypotension or bradycardia
IF: use 0.22 micron filter; central line preferable
incompatibile with heparin in IV
contains iodine
amiodarone DI
inc levels of others - inhibitor of CYP450 2C9, 2D6, 3A4, and P-gp
dec digoxin by 50%, warfarin by 30-50%
do not exceed simvastatin 20 mg/day or lovastatin 40 mg/day
additive dec HR w: non-DHP CCB, digoxin, BB, clonidine
Sofosbuvir: inc bradycia; do not use together
diltiazem/verapamil CI
HFrEF
diltiazem/verapamil warnings
may worsen HF symptoms
diltiazem/verapamil side effects
edema
arrhythmias
constipation (more w verapamil)
gingival hyperplasia
diltiazem/verapamil notes
non-DHP CCBs only CCBs used as antiarrhythmics
verapamil and diltiazem DI
additive dec HR: amiodarone, digoxin, BB, clonidine
CYP3A4 substrates: check drugs, do not take with grapefruit
substrates of P-gp; inhibitors of CYP3A4: inc conc of many drugs; lower doses of simvastatin or lovastatin
digoxin dosing
therapeutic range 0.8-2 ng/mL for AF
CrCl <50: dec dose or frequency
dec dose 20-25% when going oral to IV
digoxin monitoring
draw digoxin level
digoxin toxicity
initial toxicity s/sx: N/V, loss of appetite, bradycardia
severe: blurred/double vision; greenish-yellow halos
digoxin notes
used w/ BB or non-DHP CCB for rate control
antidote: DigiFab
hypokalemia, hypomagnesemia, hypercalcemia inc risk of toxicity
digoxin DI
substrate of P-gp - inc with inhibitors like amiodarone, diltiazem, verapamil; with amiodarone - dec digoxin 50%
additive with dec HR: amiodarone, non-DHP CCB, BB, clonidine
disopyramide warnings
proarrhythmic
anticholinergic effects
disopyramide side effects
anticholinergic effects
quinidine dosing
take with food
quinidine warnings
proarrhythmic
hemolysis risk (avoid in G6PD deficiency)
can cause positive Coombs test
quinidine side effects
drug-induced lupus erythematosus (DILE)
diarrhea
stomach cramping
cinchonism (overdose): tinnitus, hearing loss, blurred vision, HA, delirium
procainamide dosing
injection
active metabolite N-acetyl procainamide NAPA is renally cleared
therapeutic levels procainamide: 4-10 mcg/mL
procainamide BBW
granulocytosis
long-term leads to positive ANA = result in DILE
procainamide warnings
proarrhythmic
procainamide notes
metabolism by acetylation - slow acetylators risk for toxicity
lidocaine
injection
used for refractory VT/cardiac arrest
fkecainide BBW
proarrhythmic effects
flecainide CI
HF
MI
propafenone CI
HF
MI
propafenone warnings
proarrhythmic
propafenone side effects
taste disturbance (metallic)
dronedarone BBW
inc death, sstroke, HF in those with decompensated HF or permanent AF
dronedarone CI
use of strong CYP3A4 inhibitors and QT-prolonging drugs
dronedarone warnings
hepatic failure
pulmonary disease (fibrosis)
dronedarone side effects
QT prolongation
dronedarone notes
does not have iodine
little effect on thyroid
avoid use with strong inhibitors.inducers of CYP3A4 and those that inc QT interval
sotalol dosing
non-selective BB
CrCl <6-: dec frequency
sotalol BBW
adjust interval based on CrCl
concentration dec QT prolongation risk
ibutilide
injection
correct hypokalemia and hypomagnesmia prior and during
dofetilide BBW
initiate with continuous ECG monitoring
assess CrCl for >=3 days
proarrhythmic
dofetilide notes
DOC in HF
