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