arrhythmias pt 4 Flashcards
tisdale pg 32- 42 (to SVTs)
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?
LV function
hx of prior MI
significant structural HD
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?
dofetilide, dronedarone, flecainide, or propafenone
THEN
amiodarone
THEN
sotalol
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?
amiodarone or dofetilide
sotalol as last line
maybe dronedarone if no class III/IV or recent decompensated HF
when is dronedarone CI?
in pts with NYHA class III/IV or recent decompensated HF
why do pts undergoing dofetilide and sotalol initiation must be hospitalized when be treated for maintenance of sinus rhythm?
due to risk of TdP, continuous ECG monitoring for QT interval prolongation is required for 3 days
what is the first step to inpatient initiation of dofetilide/sotalol?
place pt on telemetry
continuous ECG monitoring
what is step 2 of inpatient initiation of dofetilide?
check baseline QTc
if over 440 ms, do NOT use
if under or equal to 440 ms, proceed
what is step 3 of inpatient initiation of dofetilide?
calculate CrCl
if under 20, do NOT continue its CI
use CrCl to determine dose
what is the dose of dofetilide if CrCl over 60 mL/min?
500 mcg BID
what is the dose of dofetilide if CrCl is between 40-60 mL/min?
250 mcg BID
what is the dose of dofetilide if CrCl is between 20-39?
125 mcg BID
what is step 4 of inpatient initation?
give dose based on CrCl
what is step 5 of inpatient initation of dofetilide?
post-dose adjustment 2-3 hours after 1st
check QTc interval
if after the 1st dose of dofetilide in inpatient initiation the QTc increases by less than 15%, what should the 2nd dose be?
continue current dose
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?
decrease the dose by half
so 500 mcg BID –> 250 mcg BID
250 mcg BID –> 125 mcg BID
125 mcg BID –> 125 mcg QD
what is step 6 of inpatient initiation of dofetilide?
administer 2nd dose based on QTc changes
d/c if QTc increases to over 500 ms anytime after 2nd dose
what is step 2 of inpatient initiation of sotalol?
check baseline QTc
if over 450 ms, do not use
if under 450, proceed
what is step 3 of inpatient initiation of sotalol?
calculate CrCl
if under 40, sotalol is CI
what is step 4 of inpatient initiation of sotalol?
administer first dose based on CrCl
what is step 5 of inpatient initiation of sotalol?
check QTc interval 2-4 hours after each dose
what is the dose of sotalol if a pt CrCl is over 60?
80 mg BID
what is the dose of sotalol if CrCl between 40-60?
80 mg QD
what is step 6 of inpatient initiation of sotalol?
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
when is catheter ablation used in AF?
for rhythm control to improve symptoms in pts where antiarrhythmic drugs have been ineffective, CI, not tolerated, or not preferred
when would catheter ablation be first line in AF?
in selected pts (generally younger and with fewer comorbidities) with symptomatic paroxysmal AF
used to improve symptoms and reduce progression to persistent AF
what is the most common type of supraventricular tachycardia (SVT)?
paroxysmal SVT (PSVT)
what is PSVT?
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
what are the features of SVT?
regular rhythm but a rate of 110-250 bpm
narrow QRS complexes
what are the different MOA of SVTs?
AV node (60% of cases)
Accessory AV pathway
atria
SA node
what pts are more likely to experience SVTs?
women 2x
age over 65 (5x riskier)
often occurs in individuals with no underlying CVD
what are symptoms of SVT?
neck pounding
palpitations
dizziness
weakness
lightededness
near-syncope
syncope
polyuria
what are signs of a hemodynamically unstable pt?
SBP under 90
HR over 150 bpm
ischemic chest pain
unconscious
what are goals of therapy for SVT?
terminate SVT, restore sinus rhythm
prevent recurrences
what drugs are used to terminate SVT?
adenosine
verapamil
diltiazem
BB (esmolol, propranolol, metoprolol)
what are the AE of adenosine?
chest pain (usually last 20-30s)
flushing
SOB
sinus pauses
bronchospasm
what are the drug-drug interactions of adenosine?
dipyridamole and carbamazepine accentuate response to adenosine so reduce adenosine dose by half
what is the dosing of adenosine to terminate SVT?
6mg IV rapid bolus
if no response, then 12 mg IV rapid bolus
can repeat 12 mg IV dose once
what is the MOA of adenosine in termination of SVT?
inhibits conduction through AV node, interrupting reentrant pathway
how is the termination of hemodynamically stable SVT treated?
vagal maneuvers and/or IV adenosine
if not effective/feasible, then IV BB or Diltiazem, or Verapamil
if not effective/feasible, then synchronized DCC
when determining therapy for prevention of recurrent SVT, what should be considered first?
if a pt is symptomatic or asymptomatic
if asymptomatic, then no treatment just clinical follow-up
if a pt has symptomatic SVT and is searching for therapy to prevent recurrence, what should be considered first?
if pt prefers catheter ablation
if yes, instale
if no, consider oral therapy
if a pt has symptomatic SVT, does not want catheter ablation, and does not HFrEF, what drug therapy should be considered to prevent recurrence?
BB, diltiazem, verapamil
then flecainidine, propafenone (but not in CAD pts cause CI)
then catheter ablation as last option
if a pt has symptomatic SVT, does not want catheter ablation, and has HFrEF, what drug therapy should be considered to prevent recurrence?
amiodarone, digoxin, dofetilide, sotalol
