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    Atrial Fibrillation Board Review

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    Introduction
    Atrial fibrillation is the most common cardiac arrhythmia. Fibrillation can be thought of as a worsening of flutter. These patients are at increased risk for stroke due to the potential for thrombus formation. This is because of the constant quivering from the atria. The blood will become stagnant and a clot will form. It takes a couple of days after atrial fibrillation starts for a thrombus to form.

    Signs and Symptoms
    Both types may present with palpitations, shortness of breath, and/or chest pain.

    Diagnostic Testing
    Diagnosed on ECG. Fibrillation will have an irregularly irregular rhythm without any P waves. Atrial flutter will present as a regular rhythm (regular atrial rate and irregular ventricular rate) with a saw tooth pattern. Flutter will usually have an atrial rate of 300 and a ventricular rate of 150.

    Treatment
    Unstable patients are treated the same: Cardioversion

    If the patient has been symptomatic for less than two days, you may rate control or cardiovert (may be safely done because it is too soon for a thrombus to form).

    If symptoms have been present for more than 2 days, then the possibility of thrombus exists. In this case you will want to rate control with beta blockers or calcium channel blockers. If a calcium channel blocker is used, use the non-dihyropyridines (verapamil or diltiazem). Rate control in the symptomatic patient is 85 bpm. Rate control in the asymptomatic patient is <110 bpm.

    If the patient requests cardioversion and symptoms have been present over 2 days, anticoagulate for 3 weeks before cardioversion OR order an echo to rule out a thrombus. If no thrombus exists, anticoagulate and cardiovert. If the echo shows a thrombus, you must anticoagulate for three to four weeks before cardioverting.

    Finally, make sure you provide long term anticoagulation if needed.

    First line anticoagulation options include: dabigatran (direct thrombin inhibitor), rivaroxaban (Factor Xa Inhibitor), or apixaban (Factor Xa Inhibitor). Warfarin is second line.

    Warfarin is only used first line in patients who have prosthetic heart valves and in mitral stenosis.

    We determine the need for anticoagulation with: CHA2DS2-VASc score:

    CHA2DS2-VASc

    C-CHF (1 point)
    H-Hypertension (1 point)
    A-Age > 75 (2 points)
    D-Diabetes (1 point)
    S-Stroke or TIA in past (2 points given here)
    V-Vascular Disease (1 point)
    A-Age 65-74 (1 point)
    S-Sex female (1 point)

    Score:
    0: Nothing
    1: Nothing
    >2: Anticoagulation