Atrial Fibrillation

Abdel Karim, M.D.King Hussein Medical Center, Amman, Jordan

Jim Holliman, M.D., F.A.C.E.P.Department of Emergency MedicineM. S. Hershey Medical CenterPenn State University

Atrial Fibrillation (AF) Incidence

ƒ Overall prevalence : –2.2 % in men–1.7 % in women

ƒ Age prevalence : –0.2 % at 25 to 34 years–3.0 % at 55 to 64 years

ƒ By age 75, 10 % of population has AF

AF Terminology

ƒ Chronic : present most or all the time

ƒ paroxysmal : short bursts interrupting sinus rhythm

ƒ Lone : in younger people 20 to 30 years with no apparent cause

ƒ Idopathic : in older people 50 years or older with no apparent cause

Causes of AF

ƒ Valvular heart disease –mitral stenosis–mitral regurgitation–aortic stenosis–aortic regurgitation

Causes of AF (cont.)

ƒ Nonvalvular heart disease :ƒPericarditisƒDilated and hypertrophic cardiomyopathyƒIschemic heart diseaseƒSystemic hypertensionƒCongestive heart failureƒSick sinus syndromeƒCongenital heart disease

Causes of AF (cont.)

ƒ Pulmonary diseaseƒPulmonary emboliƒAcute or chronic airway diseaseƒPrimary pulmonary hypertension

Causes of AF (cont.)

ƒ Toxic : alcohol (Acute & Chronic)ƒ Metabolic : hypomagnesemiaƒ Recent thoracotomyƒ Hyperthyroidism (occurs in 24

%)ƒ Lone or idiopathic (8 / 100,000)

Mortality and Morbidity

ƒ doubles mortality risk in patients with other heart disease

ƒ increases risk for stroke by 5 to 7 %

ƒ 45 % of cardiogenic emboli are associated with AF

ƒ risk of pericardioversion emboli increases considerably if AF has been present for more than 2 days

ƒ Are due to : rapid ventricular rate

impaired left ventricular filling

elevated left atrial pressure and decreased cardiac output

DiagnosisSymptoms

Diagnosis (cont.)Symptoms

ƒ palpitations (commonest complaint)ƒ neurological symptoms :

dizziness lightheadedness syncope or near syncope

ƒ shortness of breath

Diagnosis (cont.)Symptoms

ƒ chest pain ƒ reduction in exercise toleranceƒ aggravation of preexisting heart

failure or anginaƒ a few patients may have no

symptoms

Physical Findings

ƒ peripheral pulse : irregular pulse deficit

ƒ fluctuating systolic blood pressure

ƒ absence of "a" wave in jugular venous pulse

ƒ presence of "f" wave in jugular vein

ƒ varying intensity of first heart sound (None of these indicators can be diagnostic)

Diagnosis (cont.)ECG

ƒ fibrillary waves *called f wave *best seen in V1, II, III, and AVF *are fine to coarse *rate 350 to 600 / minute *they are pathognomonic for AF *may not be clearly present & may appear isoelectric

Diagnosis ECG

ƒ presence of missing 'p' wave

ƒ irregularly irregular QRS complexes

ƒ presence of fibrillary waves

AF : Rate

ƒ usual rate is 100 to 160 / minuteƒ if more than 160 / minute :

hyperthyroidism adrenergic

stimulationsƒ fast and wide QRS

.preexcitation syndromes (WPW)

ƒ in AF and WPW, ventricular response may be as rapid as 300 / min. or more and may degenerate to VF

ƒ sometimes it is difficult to differentiate between AF & WPW from VT

ƒ if slow rate :

medications like digitalishigh vagal tone sick sinus syndrome

Rate (cont.)

Investigations

ƒ ECGƒ Echocardiogram :

condition of mitral & aortic valves left atrial enlargement

left ventricular abnormalities pericardial effusion

ƒ thyroid function studiesƒ work up for coronary diseaseƒ work up for pulmonary emboli

Current therapy

ƒ Primary therapeutic goal is control of ventricular rate in new onset as well as chronic Atrial Fibrillation

Cardioversion

ƒ indications :preexcitation syndrome

acute hemodynamic deterioration

ƒ Rx : synchronized cardioversion 100 joules : over 60 % can be

converted 200 joules : over 80 % can be converted

If failure :procainamide IV (18 mg/kg)

and then cardioversion 360 joules

Paroxysmal AF

ƒ No Rx if :episodes are rare

self limited and well tolerated has no associated angina or heart failure nor neurological symptoms

ƒ Rx if : the patient has symptomatic episodes

AF : RxSustained AF

ƒ AF less than 2 daysƒ AF more than 2 days but TEE shows

no left atrial emboli Rx :control ventricular response

immediate cardioversion

AF : Rx

ƒ every patient deserves a chance at cardioversion

ƒ the probability of successful long-term cardioversion may be low if :

–AF has lasted for more than one year –left atrium is greater than 4.5 cm by echo

AF : Rx

ƒ acute AF more than 2 daysƒ long standing AF

Rx :.control ventricular response .anticoagulate.have patient return back in 3 to 4 weeks for cardioversion

AF : Rx

ƒ rapid ventricular rate should be treated initially with IV medication to avoid emboli, and then oral medication

ƒ anticoagulation : –warfarin for 4 weeks –maintain INR 2 to 3 times control–continue giving warfarin for 2 to 3 weeks following cardioversion

AF : Rx

ƒ control ventricular response only without restoring sinus rhythm if :–long standing well-tolerated sustained AF–patient refractory to cardioversion–patient who declines cardioversion–recurrent AF

AF : Rx

ƒ in the absence of contraindications, anticogualation is recommended even without cardioversion

AF : Rxƒ DO NOT USE –digoxin–beta blockers–calcium channel blockers

in patients with preexitation syndromes

AF : Rxƒ irregular slow

ventricular response to AF may signal the presence of AV node disease

AF : Rxƒ regular slow

ventricular response to AF may signal the presence of complete heart block often caused by digitalis toxicity

AF : RxDigoxin

ƒ used for over 200 yearsƒ commonest drug for control of AFƒ IV onset of action is 30 minutesƒ maximal response occur in 1 to 4

hoursƒ loading dose 0.1 to 0.6 mgƒ additional doses as needed 0.1 to

0.25 mg every 4 to 6 hoursƒ total dose in 24 hours is 1 mg

AF : RxDigoxin

ƒ for patients already on digoxin additional dose is 0.25 mg every 6 to 12 hours

ƒ Beta blockers or calcium channel blocker can be added if necessary

ƒ contraindications to digoxin :

*hypertrophic cardiomyopathy *WPW syndrome

AF : RxBeta Blockers

ƒ ordinarily used –Esmolol–Propranolol

ƒ particularily used in –thyrotoxicosis

ƒ adverse effects–hypotension –cardiac depression & bradyarrhythmias–bronchospasm

AF : RxBeta blockers (cont.)

ƒ Esmolol–rapid acting : half-life a few minutes–loading dose 500 mcg / kg over 1 min.– maintenance infusion 50 mcg / kg / min.–loading dose can be repeated after 5 min.–maintenance dose can be increased to 100 mcg /kg / min. as needed–effects dissipate within minutes of discontinuation of infusion

AF : RxBeta blockers (cont.)

ƒ Propranolol–can be taken orally as well as IV–dose : 1 to 3 mg boluses every 2 min. until control achieved–usual total dosage is 10 to 20 mg–effective for 4 to 10 hours–*Adverse effects : ƒ hypotension ƒ cardiac depresion

AF : RxCalcium channel blockers

ƒ verapamilƒ diltiazem

–Particularly useful in patients with pulmonary disease who cannot take beta blockers–Adverse effects :

*hypotension

*bradyarrhythmias

*cardiac depression

AF : RxCalcium channel blockers (cont.)

ƒ Verapamil–dose 5 to 10 mg given over 2 min.–if no response : additional dose after 5 to 10 min.–is usually effective for 4 to 6 hours

ƒ Diltiazem–20 mg (0.25 mg / kg) bolus over 2 min.–second bolus of 25 mg can be given 15 min. later ( if necessary)–infusion of 5 to 15 mg / hour will control the response for 24 hours

AF : RxAnticoagulation

ƒ long term Warfarin is recommended for :–mitral valve disease–previous embolic events–congestive heart failure

ƒ Aspirin 325 mg daily may be considerd in patients with nonvalvular AF

AF : RxAnticoagulation (cont.)

ƒ contraindications : –active peptic ulcer –alcoholism–gait disorders –uncontrolled hypertension–previous major bleeding–previous intracranial bleeding

ƒ incidenceƒ terminologyƒ causesƒ mortality and morbidityƒ symptomsƒ signsƒ ECG findingsƒ investigationsƒ current therapy

AF : Summary