Therapeutics - Arrhythmias Part 1 Flashcards by amanda kastel

a normal sinus rhythm (NSR) originates where? where transmitted?
what is a normal rate?

originates at SA node (pacemaker)
transmitted through the AV node to the His-Purkinje system

normal is 60-100 beats/minute

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define arrhythmia

anything other than NSR

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if SA node fails, what takes over next?

AV node/his purkinje system

but much slower

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3 categories to classify arrhythmias

above the bundle of His = supraventricular arrhythmia

below the bundle of His = ventricular arrhythmias (prolly emergency)

conduction blocks

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true or false

supraventricular arrhythmias have NORMAL QRS complexes

true

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what are the different types of conduction blocks

1st, 2nd, 3rd degree
left or right bundle branch block

essentially a diconnect between the atria and the ventricles

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what is the heart rate in sinus bradycardia

less than 60bpm

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true or false

sinus bradycardia is a supraventricular arrhythmia

true

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true or false

decreased vagal tone causes sinus bradycardia

FALSE - increased vagal tone (parasympathetic)

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2 meds that can cause sinus bradycardia

beta blockers
verapamil

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give 2 scenarios in which a patient presenting with sinus bradycardia is not a concern

when asleep
athletes - have such strong contractions that their heart doesnt need to beat as fast

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5 signs of hypoperfusion

altered mental status
hypotension
shock
angina
acute heart failure

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can sinus bradycardia cause hypoperfusion?

YES

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treatment regimen for sinus bradycardia

FIND THE CAUSE - could be from a med, MI, or just that the patient is very athletic and fit. may not need treatment

if treatment is needed - 1mg of IV atropine every 3-5 mins for a max of 3mg

if atropine fails, can use transcutaneous pacing (electrodes to set pace), dopamine, epinephrine

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dose of atropine for sinus bradycardia

1mg IV repeated every 3-5 mins for a max of 3mg

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Sinus tachycardia is what heart rate

over 100bpm

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true or false

sinus tachycardia is a ventricular arrhythmia

false - supraventricular

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2 potential causes of sinus tachycardia

-the body’s reflex to maintain blood pressure and cardiac output

medications

can be a normal response! - ie: when exercising

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can sinus tachycardia cause signs of organ hypoperfusion

yes

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what meds can cause sinus tachycardia

anything that is sympathetic

ie - epinephrine, caffeine, nicotine, cocaine

OR anything that BLOCKS the parasympathetic – atropine

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true or false

atropine makes the heart rate decrease

false - INCREASE

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treatment algorithm for sinus tachycardia (no doses yet)

like bradycardia - find the cause and correct.

can do vagal maneuver to decrease vagal tone (decrease sympathetic tone) – increasing intrabdominal pressure does this

1ST LINE - adenosine
for chronic treatment if needed - beta blocker or non DHP CCB

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as mentioned, adenosine is 1st line to treat sinus tachycardia

what is the dose

6mg IV bolus

repeat with 12mg bolus every 2 mins to max of 30mg

after the bolus - flush the line so it all gets in the body

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does atropine work right away to treat sinus tachycardia?

YES

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patient counseling points when they're given adenosine (for sinus tachycardia) what can they expect?

chest heaviness, flushing, wheeze/SOB in asthma also, may feel their heart stop at first - this is normal

patient's HR is 38bpm They are a swimmer what is course of action

NOTHING - no concern. patient is physically fit and their heart is likely very strong and doesnt have to pump very often

patient's HR is 129bpm after exercising. they are very out of breath what is course of action

NOTHING - this is a physiologic response should resolve in 1-2 mins. if it's still happening after like hours later, then we may start something

in which arrhtyhmia may a patient's EKG appear "irregularly regular" ventricular rate with no readable p waves

atrial fibrillation

the ventricular rate in an afib patient can range from ___ to ___

normal to RVR (160 - rapid ventricular rate)

"3 pillars" of atrial fibrillation

paroxysmal (7 days or less) persistent (over 7 days) permanent

true or false we do not treat paroxysmal a fib patients

FALSE - there is a high probability that the arrhythmia will come back once it is gone. we treat chronically

a big part of a fib management is reducing stroke risk. patients are ____ as indicated after bleed risk has been calculated

anticoagulated

as far as symptom management of a fib, it is really ___ vs ___

rate control vs rhythm control

overweight patient has afib what is recommendation

over 10% weight loss

true or false caffeine must be avoided in all afib patients

false - only if it triggers the afib

true or false inactivity is a risk factor for arrhythmia

true

what is the site of clot formation in afib patients

the left atrial appendage

the AFFIRM, RACE, PIAF trials all compared rate vs rhythm control in afib patients what was the ultimate conclusion

all the patients received oral anticoagulants - just differed in rate vs rhythm control really no difference - except 1-2 trials concluded that patients on antiarrhythmics had better exercise tolerance -- but that's about it

while previous trials showed that there is essentially no benefit of antiarrhythmics over rate control drugs for afib, what did a newer study conclude?

EAST-AFNET trial in 2020 showed that EARLY rhythm control showed better outcomes this conclusion is not very clinically relevant rn - but things could change

RATE CONTROL: what is the goal resting heart rate for afib patients

100-110 bpm dont NEED to get below 100

3 general rate control options for afib patients

beta blockers non DHP calcium channel bloc. digoxin

true or false theoretically, ANY beta blocker can be used for rate control in afib patients

TRUE - just need to select for comorbidities ie - pick selective if pt has asthma, 1 of the 3 options for heart failure if the pt has heart failure

for acute rate control for afib, what is the loading dose of metoprolol tartrate? maintenance?

5mg IV over 5 mins maintenance is 25mg-100mg PO BID

3 metoprolol tartrate contraindications

2nd or 3rd degree heart block sick sinus syndrome severe bradycardia (WILL SLOW HEART MORE)

2 patients in which metoprolol tartrate should be avoided (not necessarily contraindicated

hyperreactive airway (asthma) diabetics - may make it hard to see if hypoglycemic

true or false both non DHP and DHP can be used as rate control in afib patients

FALSE - only non DHP

loading dose verapamil for acute rate control for afib maintenance?

loading - 5-10mg IV over 2 mins. can repeat in 15-30 mins 10mg. then 5-10mg/hr infusion maintenance - 40-120mg PO TID (or long acting)

true or false non DHP's (verapamil and diltiazem) MUST BE AVOIDED IN HFREF

TRUE - CAN EXACERBATE HEART FAILURE

consideration when prescribing verapamil

watch for 3A4 DDI

verapamil brand names

calan, verelan

true or false digoxin is used for rhythm control in afib patients

FALSE - rate control

true or false beta blockers and non DHP calcium channel blockers are generally preferred rate control agents over digoxin, because they are better than digoxin at maintaining normal sinus rhythm

TRUE

important note about digoxin when looking for rhythm control results

the max response may take hours bc of long distribution phase

explain the dosing of digoxin and why this is the case

loading dose IV is 1-1.5mg -- split up q 6 hours. bc every patient's heart responds differently to cardiac glycosides - have to see how patient tolerates

true or false digoxin dose needs to be adjusted for renal dysfunction

true

the serum concentrations of digoxin should be kept below....

1.2mcg/L

true or false digoxin is CI in HFREF

false - it's okay if necessary

any DDI concern with dogoxin?

watch for p-glycoprotein interactions! inhibitors - vreapamil, quinidine, flecainide, amiodarone, propafenone

maintenance dose digoxin

start at 0.125mg eveyr other day eventually to 0.5mg QD

true or false digoxin is given as a single IV push for acute rate control

FALSE - given in divided doses. unpredictable response from pt to pt

1 good thing about digoxin over b blockers and non DHP CCB

no effect on blood pressure! good if the patient has low BP and we dont want to lower anymore

digoxin afib controversey

possibly increased mortality in afib patients

in general, afib patients should be STARTED on..

beta blocker if not enough and at max dose - add non DHP or can start with non DHP

if an afib patient is hemodynamically unstable, what is done right away

a cardioversion (restore regular rhythm)

elderly pt has long standing afib. heart rate is 126bpm. she is asymptomatic what to recommend

give diltiazem 20mg IV once OR verapamil loading dose of 5-10mg or can do STARTING DOSE of a beta blocker -- 100mg metoprolol tartrate is NOT appropriate

will a valsalva maneuver work in an afib patient

important note about doing a cardioversion on an afib patient

the patient MUST be anticoagulated for at least 3 weeks. this is bc when we cardiovert, a potential clot can go straight to the brain

diltiazem loading and maintenance dose for afib

loading - 0.25mg/kg IV over 2 mins can increase to 0.35mg/kg in 15 mins then 15mg/hr IV infusion 60-90mg TID or QID PO (or long acting)

safer options for an afib patient who is hemodynamically stable and has decompensated heart failure (sudden worsening of heart failure)

IV amiodarone

____ can be added to an AV nodal blockade

magnesium

Therapeutics - Arrhythmias Part 1 Flashcards

(71 cards)