arrhythmias pt 4

Question 1

if a pt is being treated for maintenance of sinus rhythm after conversion to sinus rhythm or in pts with paroxysmal afib, what is the determinants for treatment type?

Answer 1

LV function
hx of prior MI
significant structural HD

Question 2

if a pt is being treated for maintenance of sinus rhythm after conversion to sinus rhythm or in pts with paroxysmal afib and has normal LV function/no hx of MI/no significant HD, how should they be treated?

Answer 2

dofetilide, dronedarone, flecainide, or propafenone
THEN
amiodarone
THEN
sotalol

Question 3

if a pt is being treated for maintenance of sinus rhythm after conversion to sinus rhythm or in pts with paroxysmal afib and has either prior MI, significant structural HD, or HFrEF Class II, how should they be treated?

Answer 3

amiodarone or dofetilide
sotalol as last line
maybe dronedarone if no class III/IV or recent decompensated HF

Question 4

when is dronedarone CI?

Answer 4

in pts with NYHA class III/IV or recent decompensated HF

Question 5

why do pts undergoing dofetilide and sotalol initiation must be hospitalized when be treated for maintenance of sinus rhythm?

Answer 5

due to risk of TdP, continuous ECG monitoring for QT interval prolongation is required for 3 days

Question 6

what is the first step to inpatient initiation of dofetilide/sotalol?

Answer 6

place pt on telemetry
continuous ECG monitoring

Question 7

what is step 2 of inpatient initiation of dofetilide?

Answer 7

check baseline QTc
if over 440 ms, do NOT use
if under or equal to 440 ms, proceed

Question 8

what is step 3 of inpatient initiation of dofetilide?

Answer 8

calculate CrCl
if under 20, do NOT continue its CI
use CrCl to determine dose

Question 9

what is the dose of dofetilide if CrCl over 60 mL/min?

Answer 9

500 mcg BID

Question 10

what is the dose of dofetilide if CrCl is between 40-60 mL/min?

Answer 10

250 mcg BID

Question 11

what is the dose of dofetilide if CrCl is between 20-39?

Answer 11

125 mcg BID

Question 12

what is step 4 of inpatient initation?

Answer 12

give dose based on CrCl

Question 13

what is step 5 of inpatient initation of dofetilide?

Answer 13

post-dose adjustment 2-3 hours after 1st
check QTc interval

Question 14

if after the 1st dose of dofetilide in inpatient initiation the QTc increases by less than 15%, what should the 2nd dose be?

Answer 14

continue current dose

Question 15

if after the 1st dose of dofetilide in inpatient initation the QTc increases by more than 15% or to over 500 ms, what should the 2nd dose be?

Answer 15

decrease the dose by half
so 500 mcg BID –> 250 mcg BID
250 mcg BID –> 125 mcg BID
125 mcg BID –> 125 mcg QD

Question 16

what is step 6 of inpatient initiation of dofetilide?

Answer 16

administer 2nd dose based on QTc changes
d/c if QTc increases to over 500 ms anytime after 2nd dose

Question 17

what is step 2 of inpatient initiation of sotalol?

Answer 17

check baseline QTc
if over 450 ms, do not use
if under 450, proceed

Question 18

what is step 3 of inpatient initiation of sotalol?

Answer 18

calculate CrCl
if under 40, sotalol is CI

Question 19

what is step 4 of inpatient initiation of sotalol?

Answer 19

administer first dose based on CrCl

Question 20

what is step 5 of inpatient initiation of sotalol?

Answer 20

check QTc interval 2-4 hours after each dose

Question 21

what is the dose of sotalol if a pt CrCl is over 60?

Answer 21

80 mg BID

Question 22

what is the dose of sotalol if CrCl between 40-60?

Answer 22

80 mg QD

Question 23

what is step 6 of inpatient initiation of sotalol?

Answer 23

if QTc under 500 ms after 3 days, pt can be discharged
OR
dose can be increase to 120mg BID and pt followed for 3 days on this dose

Question 24

when is catheter ablation used in AF?

Answer 24

for rhythm control to improve symptoms in pts where antiarrhythmic drugs have been ineffective, CI, not tolerated, or not preferred

Question 25

when would catheter ablation be first line in AF?

Answer 25

in selected pts (generally younger and with fewer comorbidities) with symptomatic paroxysmal AF used to improve symptoms and reduce progression to persistent AF

Question 26

what is the most common type of supraventricular tachycardia (SVT)?

Answer 26

paroxysmal SVT (PSVT)

Question 27

what is PSVT?

Answer 27

a subset of SVT where pts have intermittent episodes (paroxysms) of SVT episodes start suddenly and spontaneously, can last minutes to hours, and terminate suddenly and sponatenously recur with variable frequency

Question 28

what are the features of SVT?

Answer 28

regular rhythm but a rate of 110-250 bpm narrow QRS complexes

Question 29

what are the different MOA of SVTs?

Answer 29

AV node (60% of cases) Accessory AV pathway atria SA node

Question 30

what pts are more likely to experience SVTs?

Answer 30

women 2x age over 65 (5x riskier) often occurs in individuals with no underlying CVD

Question 31

what are symptoms of SVT?

Answer 31

neck pounding palpitations dizziness weakness lightededness near-syncope syncope polyuria

Question 32

what are signs of a hemodynamically unstable pt?

Answer 32

SBP under 90 HR over 150 bpm ischemic chest pain unconscious

Question 33

what are goals of therapy for SVT?

Answer 33

terminate SVT, restore sinus rhythm prevent recurrences

Question 34

what drugs are used to terminate SVT?

Answer 34

adenosine verapamil diltiazem BB (esmolol, propranolol, metoprolol)

Question 35

what are the AE of adenosine?

Answer 35

chest pain (usually last 20-30s) flushing SOB sinus pauses bronchospasm

Question 36

what are the drug-drug interactions of adenosine?

Answer 36

dipyridamole and carbamazepine accentuate response to adenosine so reduce adenosine dose by half

Question 37

what is the dosing of adenosine to terminate SVT?

Answer 37

6mg IV rapid bolus if no response, then 12 mg IV rapid bolus can repeat 12 mg IV dose once

Question 38

what is the MOA of adenosine in termination of SVT?

Answer 38

inhibits conduction through AV node, interrupting reentrant pathway

Question 39

how is the termination of hemodynamically stable SVT treated?

Answer 39

vagal maneuvers and/or IV adenosine if not effective/feasible, then IV BB or Diltiazem, or Verapamil if not effective/feasible, then synchronized DCC

Question 40

when determining therapy for prevention of recurrent SVT, what should be considered first?

Answer 40

if a pt is symptomatic or asymptomatic if asymptomatic, then no treatment just clinical follow-up

Question 41

if a pt has symptomatic SVT and is searching for therapy to prevent recurrence, what should be considered first?

Answer 41

if pt prefers catheter ablation if yes, instale if no, consider oral therapy

Question 42

if a pt has symptomatic SVT, does not want catheter ablation, and does not HFrEF, what drug therapy should be considered to prevent recurrence?

Answer 42

BB, diltiazem, verapamil then flecainidine, propafenone (but not in CAD pts cause CI) then catheter ablation as last option

Question 43

if a pt has symptomatic SVT, does not want catheter ablation, and has HFrEF, what drug therapy should be considered to prevent recurrence?

Answer 43

amiodarone, digoxin, dofetilide, sotalol