anti-arrhythmics Flashcards

1
Q

3 ways to counter arrhythmias

A

decrease automaticity, increase refractoriness, decrease conduction velocity

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2
Q

5 ways to decrease automaticity

A

increase threshold, decrease phase 4 slope, increase AP duration, slow SA/AV depolarization, increase maximum diastolic potential (more negative)

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3
Q

3 Class IA

A

quinidine, procainamide, disopyramide

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4
Q

2 class IB

A

Lidocaine, mexilitine

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5
Q

2 class IC

A

flecainide, propafenone

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6
Q

5 class II (beta blockers)

A

esmolol, metoprolol, propranolol, atenolol, timolol

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7
Q

5 class III

A

amiodarone, dronedarone, dofetilide, sotalol, ibutilide

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8
Q

2 class IV

A

verapamil, diltiazem

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9
Q

Class IA target/mech

A

Na channels (slow action potential, flatter phase 0 slope), also affect potassium (prolong AP duration/repolarization)

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10
Q

Class IB target/mech

A

weak Na block, shortened repolarization

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11
Q

Class IC target/mech

A

strong Na block (affect on phase 0) and minimal repolarization effect

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12
Q

overall mech for class I

A

slow the resetting of fast Na+ channels after AP- makes them selective for rapidly depolarizing tissue

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13
Q

IA toxicities

A

prolonged QT and torsade

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14
Q

IC toxicities

A

proarrhythmic, avoid w/ pts who have structural abnormalities

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15
Q

class II mech for decreasing automaticity

A

decrease phase 4 slope by competing w/ adrenergic stimulation and slowing HCN channel opening

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16
Q

class III mech for decreasing automaticity

A

block K+ channels and prolong repolarization

17
Q

class III toxicities

A

prolonged QT and torsade

EXCEPT amiodarone

18
Q

class IV mech to lower automaticity

A

slow depolarization in nodal cells by blocking Ca++ channels (responsible for phase 0 upstroke in pacemakers)

19
Q

adenosine mech for lowering automaticity

A

increase (more negative) maximum diastolic potential, bind to specific adenosine receptors, promotes K+efflux and inhibits adenylate cyclase (and cAMP) and thus the Ca++ channels as well

20
Q

PK of adenosine

A

short half life less than 30 seconds, must be administered by rapid IV bolus

21
Q

ways to inhibit reentrant arrhythmias

A

increase refractory period, slow conduction

22
Q

how to increase refractory period?

A

class IA and III- block K+ channels and repolarization, prolonging AP

Class IA-C and adenosine- inhibit recovery of Na+ (Ca++ for adenosine) channels prior to next AP, does not prolong current AP

23
Q

why want to slow conduction velocity?

A

blocking/slowing impulse along AV node can protect ventricles from atrial arrhythmias

24
Q

how to slow AV conduction?

A

Class II beta blockers (slow HCN Na+ influx) or class IV Ca++ blockers (slow Ca++ phase 0) or adenosine (hyperpolarization at maximum diastolic potential)

25
side effects of amiodarone
neuropathy, night terrors, nausea, discoloration (blue), pulmonary fibrosis, thyroid problems, corneal deposits
26
Tx for acute termination of SVT
block AV node- vagal maneuvers, adenosine
27
long term management of AVNRT
ablation of slow pathway or beta blocker
28
long term managment of AVRT
ablation of accessory pathway and/or flecanaide/propafenone (class IC) when there is pre-excitation (slows accessory) ablation of accessory pathway and/or beta blocker (slows AV node) when no pre-excitation
29
managment of a fib | depends on presence of structural heart disease
anticoag stroke prevention, rate control (class II, class IV, digoxin), rhythm control (when symptomatic or low EF), can do ablation or use class IC or III)
30
acute management of VT
cardioversion if unstable/ACLS w/ heart disease: cardioversion, procainamide, lidocaine, or amiodarone w/o heart disease: for outflow VT use beta blocker and for fascicular VT use verapamil
31
chronic managment of VT
AICD (automatic implanted cardioverter defib), up beta blocker, prevention w/ sotalol, amiodarone, or ablation
32
why add rhythm control for a fib?
Sx despite rate control, LV dysfunction, reduce hospitalization
33
rhythm control AAD options for a fib?
propafenone, flecanide (IC), sotalol, dofetilide, amiodarone, dronadarone (III)