ATRIAL FIBRILLATION

Epidemiology: 10% of population by age 90.

Basic principles:

1. Identify cause- ECHO

a. Structural HD: HTN, CAD, valve dz, DCMP, post surgical, pericarditis, congenital dz (ASD)

b. Systemic: surgery, infection, hyper/hypothyroidism, electrolyte disturbance, malignancy, EtOH, sarcoid, pheo, amyloid

1. Control RVR- *IF wide complex, consider WPW(DC cardioversion

Setting	Drug	Dose	Comments
Acute
RVR, HD unstable			Urgent DC cardioversion
RVR, symptomatic	Diltiazem	1. Bolus 20mg IV over 2 min 2. 15 min later, 25mg IV over 2 min (if needed), THEN 5-15mg/hr	Rapid acting, well tolerated
	Verapamil	5-10mg IV, repeat after 10 min	Hypotension may occur
	Metoprolol	5mg IV Q5 min X 3	Rapid, useful post- operative
	Esmolol	0.5mg/kg IV over 1 min, THEN 0.05mg/kg/min	Short acting, hypotension common
	Digoxin	0.25-0.5mg (1 mg/24 hr)	Moderate efficacy, onset 1-6 hrs.
Chronic
RVR	Verapamil	120-180mg PO QD	Rest and exercise control
	Diltiazem	90-360mg PO QD	As above
	Atenolol	25-100mg PO QD	Esp effective at controlling exercise rate
	Digoxin	0.1-0.75mg PO QD	May not control exercise rate (primarily vagolytic)
Refractory			AV ablate, PM

1. ?Restore SR

a. 30-50% revert spontaneously in 48H

b. DC cardioversion- 200, 360J

-indicated for first episode of AF

-RELATIVE contraindications: 1)poor prognosis, 2)high risk anesthesia, 3)long-standing, 4)LA >6cm

-IF < 48H, heparinize, then cardiovert

-IF > 48H, anticoagulate 3-4 wks, then cardiovert, OR TEE to rule out thrombus in LA

-continue antigoagulation 3-4 wks after cardioversion

c. Chemical- Ibutilide

1. ?Maintain SR- see below

Drug	Oral Dose	Useful in	Avoid in
Class IA
Quinidine gluconate	324-648mg Q8-12H	Chronic renal failure	CHF, liver failure
Procainamide	0.5-1.5g Q6H	Men, short-term therapy	Renal failure, CHF, Joint disease
Disopyramide	200-44mg Q12H	Women	Older men at risk for urinary retention, CHF, Glaucoma, Renal failure
Class IC
Flecainide	75-150mg Q12H	Failure of Class IA drugs	Any LV dysfunction, CAD
Propafenone	150-300mg Q8H	Failure of Class IA drugs	Any LV dysfuntion
Class III
Sotalol	80-240mg Q12H	Failure of IA or IC, may be used with moderate LV dysfunction	Where beta blocker is contraindicated
Amiodarone	1200mg QD for 5 days followed by 400mg QD for 1 mo, then 200-400mg QD	Severe LV dysfunction, failure of other drugs, CHF, renal failure	Young pt, pulmonary disease

2. Anticoagulate- risk factors include 1)structural heart disease- depressed LV function, LA enlargement, CHF, valve disease, and 2)systemic risk factors for stroke- prior embolic event, HTN, DM.

a. IF younger than 60 w/o structural heart disease or risk factors for stroke,(ASA

b. IF younger than 75 w/ structural hear disease or risk factors for stroke(Coumadin, INR 2.0-3.0

c. IF older than 75(consider NO anticoagulation

1. IF single episode of AF converted to NSR for more than 3-6 mos(NO anticoagulation

Gilligan, et al. Am J Med 1996;101:413-421