Arrhythmias pt 1

Question 1

what part of the heart starts the spark for cardiac conduction system?

Answer 1

SA (sinus) node

Question 2

how does depolarization happen in the heart?

Answer 2

depolarization reaches the end of the cell which depolarizes the cell next to it and then so on

Question 3

what is phase 0?

Answer 3

depolarization
right before the Q wave
up and down on the action potential wave
sodium current

Question 4

what is phase 1?

Answer 4

rapid repolarization
potassium current (Ito)
Q interval

Question 5

what is phase 2?

Answer 5

calcium current
plateau
QT interval

Question 6

what is phase 3?

Answer 6

repolarization of K currents (Iks, Ikr)
T wave

Question 7

what are the questions to ask if an ECG is a normal sinus rhythm?

Answer 7

is there a p wave in front of very QRS complex?
is there a QRS complex after every p wave?
Is the interval between the R waves equal?
Is the heart rate between 60-100 bpm?

Question 8

what is the 300-150-100 method?

Answer 8

measures bpm
find a R wave on a box then count off starting at 300 then 150 then 100 then 75 then 60 for each big box passed
where ever the next R wave falls is the bpm

Question 9

what is 5 big box method?

Answer 9

5 big boxes on an ECG is roughly 1 second so you can count the number of waves in each box will tell you the bpm

Question 10

what is the normal value of the PR interval?

Answer 10

0.12 - 0.2 seconds
120-200 ms

Question 11

what are example of drugs that change the PR interval?

Answer 11

BB
CCB
amiodarone
digoxin

Question 12

what is the normal duration for QRS?

Answer 12

0.08-0.12 seconds
80-120 ms

Question 13

what is normal value for QT interval?

Answer 13

0.38-0.46 seconds
380-460 ms

Question 14

what is the normal time of the QTc interval for men?

Answer 14

0.36-0.45 seconds
360-450 ms
testosterone shortens it

Question 15

what is the normal time for QTc interval for women?

Answer 15

0.36-0.45 seconds
360-460 ms

Question 16

how would one find a corrected QT interval?

Answer 16

take the QT interval and divided by the square root of respiration rate

Question 17

when does torsades de pointes occur?

Answer 17

when the QTc interval exceeds 500 ms there is an increased risk

Question 18

what is torsades de pointes?

Answer 18

drug-induced arrhythmia due to lengthening of action potential too much
no p waves

Question 19

what are the drug classes that can induce torsades de pointes when on long-term?

Answer 19

anti arrhythmic
antimicrobials
antidepressants
antipsychotics
anticancer
methadone

Question 20

what anti-arrhythmics cause TdP?

Answer 20

procainamide
flecainide
amiodarone
dronedarone
ibutilide
dofetilide
sotalol
Phineas and Ferb Are Doing IDiot Stuff

Question 21

what antimicrobials can induce TdP?

Answer 21

macrolides - azithromycin, clarithomycin, erythromycins
fluoroquinolones - levofloxacin, moxifloxican, ciprofloxacin

Question 22

what antidepressants can induce TdP?

Answer 22

citalopram
escitalopram
clomipramine
desipramine
lithium
mirtazapine
venlafaxine

Question 23

what antipsychotics can induce TdP?

Answer 23

chlorpromazine
haloperidol
pimozide
thioridazine
aripiprazole
clozapine
iloperidone
olanazapine
paloperidone
quetiapine
risperidone
sertindole
ziprasidone

Question 24

what anticancer drugs can cause TdP?

Answer 24

arsenic trioxide
eribulin
vandentaib (and most drugs ending in nib)

Question 25

what are examples of supraventricular arrhythmias?

Answer 25

sinus bradycardia atrioventricular (AV) nodal block sinus tachycardia atrial fibrillation supraventricular tachycardia

Question 26

where do supraventricular arrhythmias occur?

Answer 26

above the ventricles

Question 27

what are the types of ventricular arrhythmias?

Answer 27

premature ventricular complexes (PVCs) ventricular tachycardia ventricular fibrillaton

Question 28

what are the features of sinus bradycardia?

Answer 28

HR under 60 bpm impulse originates in sinoatrial (SA) node

Question 29

what is the MOA of sinus bradycardia?

Answer 29

decreased automaticity of the SA node

Question 30

what are etiologies of sinus bradycardia?

Answer 30

MI/ischemia abnormal sympathetic/parasympathetic tone electrolyte abnormalities (high K/Mg) drugs idiopathic (sick sinus syndrome)

Question 31

what are examples of drugs that can induce sinus bradycardia?

Answer 31

digoxin BB diltiazem, verapamil amiodarone dronedarone ivabradine

Question 32

when a drug is suspected to cause sinus bradycardia, how should it be treated?

Answer 32

remove it and see if the HR returns to normal, need to know half-life though for this for specifically diltiazem/verapamil, just stop it entirely

Question 33

what are symptoms of sinus bradycardia?

Answer 33

hypotension - due to not generating enough CO dizziness, fainting (syncope)

Question 34

when is treatment necessary for sinus bradycardia?

Answer 34

only if pt is symptomatic

Question 35

what is the first line treatment of sinus bradycardia?

Answer 35

atropine 0.5-1 mg IV, repeat as required every 3-5 minutes up to max dose of 3 mg

Question 36

what is the AE of atropine?

Answer 36

tachycardia urinary retention blurred vision dry mouth mydriasis

Question 37

how should sinus bradycardia be treated if pt is unresponsive to atropine?

Answer 37

transcutenous pacing OR infusion of B-agonists with rate-accelerating effects

Question 38

what is transcutaneous pacing?

Answer 38

electrical jolt to pt while figuring out next steps for sinus bradycardia

Question 39

what are B-agonist used to tx sinus bradycardia?

Answer 39

dopamine 5-20 mcg/kg/min epinephrine 2-10 mcg/min titrate to desired effect isoproterenol 20-60 mcg IV bolus based on HR response

Question 40

how should a person who recently had a heart transplant or spinal cord injury be treated for symptomatic or hemodynamically unstable sinus bradycardia?

Answer 40

amiophylline via IV over 20-30 minutes theophylline via IV (transplant) or PO (spinal cord) titrated to effect

Question 41

for patients who have sick sinus syndrome induced sinus bradycardia, how should they be treated?

Answer 41

long-term treatment of permanent pacemaker which titrated HR to 60-70 bpm