Arrhythmias pt 2

Question 1

how many ppl in the US have Afib?

Answer 1

around 6 million with prevalence increasing with advancing age
8% of people age 80-89

Question 2

how is atrial activity characterized in Afib?

Answer 2

chaotic and disorganized
no organize atrial depolarization
atrials are quivering rather than contracting

Question 3

what is the ventricular rate associated with Afib?

Answer 3

120-180 bpm

Question 4

how are P waves and rhythm characterized in Afib?

Answer 4

P waves are absent
Rhythm is irregularly irregular

Question 5

during Afib, how does blood fill the ventricles?

Answer 5

relies on changes of pressure
leads to 70-75% of normal blood filling LV/RV

Question 6

what is stage 1 of Afib?

Answer 6

presence of modifiable and nonmodifiable risk factors associated with Afib

Question 7

what is stage 2 of AF?

Answer 7

pre-AF
evidence of structural or electrical findings further predisposing a pt –> atrial enlargement, frequent atrial premature beats, atrial flutter

Question 8

what is stage 3 of AF?

Answer 8

diagnosed AF
can be 3A, 3B, 3C, or 3D

Question 9

what is stage 3A?

Answer 9

paroxysmal AF
most common
starts and stops suddenly and usually resolves within hours
definition - AF that is intermittent and terminates within 7 days of onset

Question 10

what is stage 3B?

Answer 10

persistent AF
defintion - AF that is continuous and sustained for longer than 7 days and requires interventions

Question 11

what is stage 3C?

Answer 11

long-standing persistent AF
definition - AF that is continuous for more than 12 months in duration

Question 12

what is stage 3D?

Answer 12

successful AF ablation
definition - freedom from AF after percutaneous or surgical intervention to eliminate AF

Question 13

what is stage 4?

Answer 13

permanent AF
1/3 of pt progress here
definition - no further attempts at rhythm control after discussion between the pt and clinical

Question 14

do antiarrhythmics work in stage 4?

Answer 14

no because the pt will never have normal sinus rhythm again

Question 15

what are the MOA of AF?

Answer 15

abnormal atrial automaticity
—- pulmonary vein automaticity —-
atrial re-entry (competing waves of depolarization, increase HR)

Question 16

what are the risk factors of AF?

Answer 16

advancing age
cig smoking
sedentary lifestyle
alcohol
obesity
HTN, DM, CAD, HF, CKD
obstructive sleep apnea
valvular HD
familial (genetic)
idiopathic

Question 17

what are the etiologies of reversible Afib?

Answer 17

hyperthyroidism
Sepsis
thoracic surgery like CABG, lung resection, esophagectomy

Question 18

what are the symptoms of AF?

Answer 18

may be asymptomatic
palpitations
dizziness
fatigue
lightheadedness
SOB
hypotension
syncope
angine
exacerbation of HF symptoms

Question 19

if a pt has AF, what are they more likely to develop?

Answer 19

stroke/systemic embolism (5x)
HF (3x)
dementia (2x)
mortality (2x)

Question 20

why is dementia associated with AF?

Answer 20

due to small emboli forming occlusions in the brain

Question 21

what are lifestyle and risk factor modifications of AF?

Answer 21

weight loss if overweight or obese (10%)
physical fitness (210 vigorous/week)
smoking cessation
eliminate alc consumption
BP control if HTN
optimal glucose and A1c management in DM

Question 22

what are goals of AF drug therapy?

Answer 22

prevent thrombosis and embolism leading to stroke/systemic embolism
slow ventricular response
convert AF to normal sinus rhythm
maintain sinus rhythm (reduce frequency of episodes)

Question 23

how can ventricular response be slowed in AF?

Answer 23

by inhibition conduction of atrial impulse to ventricles

Question 24

what are the components of CHADS-VASc score?

Answer 24

1pt - congestive HF, HTN, DM, Vascular disease (prior MI, PAD, or aortic plaque), age 65-74, female
2 pt - age 75+, stroke/TIA/TE history

Question 25

when are oral anticoags recommended in AF pts?

Answer 25

CHADS-VASc score over 2 in men and over 3 in women

Question 26

when are oral anticoags reasonable in AF pts?

Answer 26

CHADS-VASc score of 1 in men, 2 in women

Question 27

what is the preferred anticoag treatment in most AF pts?

Answer 27

DOACs exceptions for warfarin

Question 28

when is warfarin only preferred in AF?

Answer 28

in mechanical heart valves (target INR 2.5-3.5) AF associated with heart valve disease (mod-severe mitral valve stenosis, target INR 2-3)

Question 29

when is warfarin or apixaban (eliquis) preferred?

Answer 29

end-stage CKD with CrCl under 15 mL/min hemodialysis

Question 30

what is the antidote of dabigatran?

Answer 30

idarucizumab

Question 31

what is the antidote of rivaroxaban, apixaban, and edoxaban?

Answer 31

andexanet alfa

Question 32

when is rivaroxaban and apixaban CI?

Answer 32

in pts receiving drugs that are combined strong p-glycoprotein and CYP3A4 inducers like rifampin, phenytoin

Question 33

when should normal apixaban dose be lowered?

Answer 33

if SeCr over 1.5 mg/dL over 80 yrs weight under 60 kg

Question 34

how do p-glycoprotein substrate INHIBITORS affect DOACs?

Answer 34

increase plasma concentrations through inhibitors like KTZ, verapamil, amiodarone, dronedarone, clarithromycin

Question 35

how do p-glycoprotein substrate INDUCERS affect DOACs?

Answer 35

reduce plasma concentrations by inducers such as phenytoin, rifampin, carbamazepine, St Johns wort

Question 36

how should anti-coags be monitored in AF?

Answer 36

INR in warfarin therapy at weekly intervals during initiation, when stable monthly at least

Question 37

what drugs are used for ventricular rate control in AF?

Answer 37

diltiazem verapamil BB digoxin amiodarone

Question 38

what are the AE of diltiazem/verapamil?

Answer 38

hypotension HF exacerbation (dont use in HFrEF) bradycardia AV block constipation (oral V only)

Question 39

what are important drug-drug interactions of diltiazem/verapamil?

Answer 39

inhibits CYP3A4 - cyclosporine, statins V also inhibits p-glycoprotein - digoxin/dofetilide

Question 40

what BB are used in AF?

Answer 40

esmolol propranolol metoprolol tart and succ

Question 41

when would BB exacerbate HF in AF pts?

Answer 41

if dose too high or dose increased aggressively

Question 42

what is the MOA of diltiazem, verapamil, and BB in AF?

Answer 42

direct AV node inhibition

Question 43

what is the MOA of digoxin in AF?

Answer 43

vagual stimulation Direct AV node inhibition

Question 44

what is the MOA of amiodarone in AF?

Answer 44

BB and CCB

Question 45

what is the AE of digoxin?

Answer 45

NV anorexia ventricular arrhythmias

Question 46

what are important drug-drug interactions of digoxin?

Answer 46

amiodarone and verapamil inhibit dig elimination

Question 47

what are the AE of amiodarone?

Answer 47

hypotension (IV only) bradycardia blue-grey skin discoloration photosensitivity corneal microdeposits pulmonary fibrosis hepatotoxicity hypothyroidism/hyperthyroidism

Question 48

what are important drug-drug interactions of amiodarone?

Answer 48

inhibits CYP P450 - warfarin, statins inhibits p-glycoprotein - digoxin

Question 49

why is amiodarone not commonly used?

Answer 49

due to long half life (2 months) and a lot of AE