Atrial Fibrillation

The Big Asthma Lie

Herbal Treatment for Asthma

Get Instant Access

Classification {JACC 2006:48*149)

• Paroxysmal (self-terminating) vs. persistent (sustained -7 d) vs. permanent (typically

> 1 y and when cardioversion has failed or is foregone)

• Valvular (rheumatic MV disease, prosthetic valve, or valve repair) vs. nonvalvular

• Lone AF age <60 and w/o clinical or echo evidence of cardiac disease (including HTN) Epidemiology and etiologies

• 1% of population has recurrent AF (8% of elderly); mean age at presentation 75 y

Cardiac: CHF, myo/pericarditis, ischemia/Ml. hypertensive crisis, cardiac surgery Pulmonary: acute pulmonary disease or hypoxia (eg. COPD flare, pneumonia). PE Metabolic: high catecholamine states (stress, infection, postop. pheo). thyrotoxicosis Drugs: alcohol ("holiday heart"), cocaine, amphetamines, theophylline, caffeine

• Chronic t age. HTN. ischemia, valve dis. (MV. TV. AoV). CMP. hyperthyroidism, obesity

Pathophysiology (NEJM 1998.339:659; Ort 1995:92:1954)

• Commonly originates from ectopic foci in atrial "sleeves" in the pulmonary veins

• Loss of atrial contraction HF; LA stasis thromboemboli; ? tachycardia CMP Evaluation

• H&P. ECG. CXR. echo (LA size, presence of thrombus, valves. LV fxn, pericardium).

TFTs. ? r/o ischemia (AF unlikely due to ischemia in absence of other sxs)

Figure 1-5 Approach to acutc Af

New or Recent-Onset AF -

i stable

( Urgent ' cardioversion

Spont. cardioversion (Occur* win 2« h in 50*7% acute AF)

(IB or CCB IV UFH If admitting & cardio -erting (see Table) <vw warfann

Spont. cardioversion (Occur* win 2« h in 50*7% acute AF)

3. Consider cardioversion

low nsk of stroke or high risk of stroke

3. Consider cardioversion

low nsk of stroke or high risk of stroke

Cardioversion

(etectrxal and'or pharmacologic) / |_a Empiric anticoag a thi thromb. warfann x ¿3 w

(Adapted from NEJM 2004:351:2-408: JACC 2006:48:e149)

(Adapted from NEJM 2004:351:2-408: JACC 2006:48:e149)

Rate Control for AF (Goal HR 60-80,90-115 with exertion)

Agent

Acute (IV)

Maint. (PO) Comments

co

Verapamil

5-10 mg over 2' may repeat in 30'

120-360 mg/d 1 BP (Rx w/ Ca glue) in divided doses Watch for CHF

u

Diltiazem

0.25 mg/kg over 2' may repeat after 15' 5-15 mg/h infusion

120-360 mg/d Preferred if COPD in divided doses Can T dig levels

s.

Metoprolol

5 mg over 2' may repeat q 5' x 3

25-100 mg bid 1 BP (Rx w 1 glucagon) or tid Watch for CHF &

Propranolol

1 mg q 2'

80-240 mg/d bronchospasm in divided doses Preferred if CAD

Digoxin

(takes h)

0.25 mg q2h up to 1.5 mg

0.125-0.375 mg Consider in HF or low BP qd (adj for CrCI) Poor exertional HR Ctrl

Amiodarone

150 mg over 10' — 0.5-1 mg/min

IV ßB. CCB. and digoxin contraindicated if evidence of WPW (ie. preexcitation or WCT)

IV ßB. CCB. and digoxin contraindicated if evidence of WPW (ie. preexcitation or WCT)

Strategies for recurrent AF

• Rate control: goal HR 60-80. 90-115 w/ exertion (see above table for options)

AV node ablation + PPM as a last resort (nejm 2001:344 1043; nejm 2002:346 2062)

• Rhythm control: no clear survival benefit vs. rate Ctrl; perhaps b/c of premature d/c of anticoag & antiarrhythmic drugs can be proarrhythmic (affirm, nejm 2002:347:1825.1834)

• Anticoagulation (if indicated, see below) to prevent thromboemboli. whether rate or rhythm strategy

Antiarrhythmic Drugs (AAD) for AF

Agent

Conversion

Maintenance

Comments

Amiodarone

5-7 mg/kg IV over 30-60' - 1 mg/rnin to achieve 10 g load

200-400 mg qd (most effective drug)

IQTbutTdP rare Pulm. liver, thyroid toxicity ✓ PFTs. LFTs.TFTs

III

Ibutilide

1 mg IV over 10' may repeat x 1

nil

Contraindic. if i K or T QT t QT, 3-8% risk of TdP Mg 1-2 g IV to 1 risk TdP

Dofetilide

0.5 mg PO bid

0.5 mg bid

T QT, t risk of TdP 1 dose if CrCI < 60

Sotalol

n/a

90-160 mg bid

/ for 1 HR.! QT Need to renally adjust

Flecainide

300 mg PO x 1

100-150 mg bid

PreRx w/AVN blocker

IC

Propafenone

600 mg PO x 1

150-300 mgtid

Contraindic. if structural or ischemic heart disease

IA

Procainamide

10-15 mg/kg IV over 1 h

1-2 g bid of slow release

• PreRx w/AVN blocker

(Adapted from NEJM 2001:344:1067; Anno ft 2003:139:101&;ACC 2006;48:c149)

(Adapted from NEJM 2001:344:1067; Anno ft 2003:139:101&;ACC 2006;48:c149)

Cardioversion

• Consider pharm or DC cardioversion in Pts w/ 1st episode of AF or in those w/ sx if AF -48 h. 2-5% risk stroke w/ cardioversion (pharm. or electric) either TEE to r/o thrombus or therapeutic anticoagulation for -3 wks prior

• Likelihood of success dependent on AF duration (better < 7d) and atrial size

• Consider preRx w/ antiarrhythmic drugs (especially if 1st attempt fails)

• For pharmacologic cardioversion, class III and IC drugs have best proven efficacy

• Even if SR returns, atria mechanically stunned. Also, greatest likelihood of recurrent AF

in first 3 mos after return to SR. must anticoagulate postcardioversion -4-12 wks

• "Pill-in-pocket": if IC drugs have been safely tolerated in Pts w/o ischemic or structural heart disease, can take as outPt prn if recurrent sx AF (nejm 2004:351 2384) Maintenance of SR (as necessary)

• CHF — dofetilide or amiodarone (N£/m 2007:356935) Nonpharmacologic therapy

• Radiofrequency ablation (circumferential pulm. vein isolation): 80% success (although often requires repeat procedures); consider if J EF or failed antiarrhythmic Rx

(nejm 2004.351 2373 A 2006:354 934. jama 2005:293:2634)

• Surgical "maze" procedure (70-95% success rate) option if undergoing cardiac surgery

• Left atrial appendage obliteration in Pts w/ AF undergoing cardiac surgery i risk of stroke Anticoagulation (jacc 2006:48x149; Ok* 2004:126:429S)

• Risk of stroke ff in valvular AF. anticoagulate all

• Risk of stroke 4.5% per year in nonvalvular AF; risk factors include:

prior stroke/TIA. DM. HTN. older age (¿65 y). HF. ? CAD

echo: EF <35%. dense spontaneous echo contrast in LAA. ? T LA size. I Ao athero

• Risk of stroke in recurrent paroxysmal AF persistent AF permanent AF; AFL AF

• Treatment options warfarin (INR goal 2-3. nejm 1996:335 540 A 2003:349:1019) - 61% i stroke aspirin (81-325 mg qd): better than placebo (19% i stroke) but inferior to warfarin aspirin - clopidogrel inferior to warfarin (ACTiVE-w. Lonce« 2006:367:1903)

valvular AF, prior stroke/TIA, or - 2 other risk factors - warfarin 1 risk factor • warfarin or ASA (if age 60-74 and no other risk factors -» ? ASA) if Pt not good candidate for warfarin (t risk of bleeding/falling) .ASA + ? clopidogrel lone AF . aspirin or no Rx

Was this article helpful?

0 0
Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

Get My Free Ebook


Post a comment