Atrial fibrillation – an irregular, usually rapid supraventricular rhythm caused by simultaneous discharge and reentry at multiple atrial fociCAUSES
Serious cardiopulmonary causes |
Other causes |
Acute myocardial infarction or acute coronary syndrome | Hyperthyroidism |
Pulmonary embolism | Ethanol use (“holiday heart”) |
Cardiomyopathy | Hypothermia |
Restrictive heart disease | Drugs: sympathomimetics, cocaine, amphetamine derivatives, ephedra |
Chronic obstructive pulmonary disease | Metabolic causes: hypokalemia |
Sleep apnea | Idiopathic: lone AF |
Hypertension | |
Valvular heart disease | |
Left ventricular hypertrophy | |
Left ventricular diastolic dysfunction | |
Congestive heart disease | |
Sick sinus syndrome | |
Pericarditis | |
Post-cardiac surgery |
History
HPI
- Onset, duration (< or > 48 hours) and frequency
- Symptoms: palpitations, fatigue, dyspnea
- chest pain?
- fevers/ constitutional symptoms assoc’d with sepsis
- EtOH ingestion, drug use
PMHx
- CAD, MI, valve disease, CHF, other cardiac abnormalities
- thyroid disease
- COPD
Physical
- Vitals – irregularly irregular pulse +/- tachycardia
- CV – murmurs, S3 gallop, increased JVP, pedal edema
- Respiratory – crackles
- Neuro – assess for embolic complications
Investigations
- ECG – no organized P waves, chaotic baseline, irregularly irregular ventricular response, narrow QRS
- Initial labs – CBC/diff, elytes (hypokalemia can cause Afib), glucose, TSH, free T4, CXR
- Trop/ CK – if ACS suspected
- CT chest – possible PE
- ABG – CO poisoning, hypercarbia, shock, acidemia
- Echo – not usually used in acute assessment
- Holter monitor – used in some patients with paroxysmal Afib
Management
Dependent upon several factors: acuity of onset, associated symptoms, hemodynamic status, and the duration of the dysrhythmia (<48 h or >48 h).
Options:
- RATE CONTROL
- B-blockers, diltiazem, verapamil
- if CHF, use amiodarone or digoxin
- initial management in hemodynamically stable patients
Note: carotid massage may slow ventricular rate
- THROMBOEMBOLISM PROPHYLAXIS
- Acute: heparin
- Chronic: use CHADS2 score (see below) to determine appropriate Rx
- 0 stroke risk factors – ASA 81 – 325 mg daily
- 1 mod RF – ASA or warfarin
- > 1 mod RF or any high risk factor – warfarin (goal INR 2.0 – 3.0)
- RESTORE SINUS RHYTHM
- New onset
- Self-limited episode – no antiarrhythmic drugs necessary if serious symptoms absent
- if high stroke risk, anticoagulation beneficial
- Persistent
- rate control + anticoagulation OR
- cardioversion
-
- Chemical – amiodarone, sotalol, diltiazem, Class I anti-arrhythmic agent
- Electrical – synchronized DC cardioversion
- if duration <48 h, can cardiovert without anticoagulation
- if duration>48h, MUST anticoag 3 wks prior/ 4 wks following cardioversion
- use CHADS2 score to assess need for longterm anticoagulation
-
- Recurrent/ Permanent
- Brief episodes or minimal symptoms- rate control + anticoag
- Prolonged or bothersome symptoms – antiarrhythmic drugs
- Permanent Afib – rate control + anticoag (use CHADS2 score)
- New onset
Risk Factor | Points |
|
> 75 years | 1 | |
diabetes | 1 | |
hypertension | 1 | |
congestive heart failure | 1 | |
Prior stroke/TIA | 2 |
CHADS 2 score |
Yearly risk of stroke (%) |
Anticoagulation |
0-1 |
1.9-2.8 |
aspirin 81-325 mg |
2-3 |
4.0-5.9 |
coumadin |
4-6 |
8.5-18.2 |
coumadin |