Atrial fibrillation

Vignette says a 55 year old female presents to the emergency department with a sudden onset of palpitations that started 30 minutes ago; She describes the sensation as her "heart racing" and feels lightheaded and dizziness but denies chest pain, shortness of breath or syncope; She states that she had similar episodes in the past that resolved spontaneously; She has a history of coronary artery disease; Vital signs show pulse rate of 180 beats/min, blood pressure of 110/70 mm of Hg, respiratory rate of 16 breaths/min, oxygen saturation of 96% in RA and temperature of 98.2 F; Laboratory studies show CBC, serum electrolytes, BMP, TSH and HbA1C within normal limits; ECG shows absent P waves, irregularly irregular rhythm (i.e. irregular R-R interval) and narrow QRS complexes; Transesophageal echocardiography shows thrombus in the left atrium; Diagnosis?

Diagnosis is Atrial fibrillation. 

Atrial fibrillation

Types:- 
1. Paroxysmal AFib:- Episodes of AFib shorter than 7 days, either self terminated or cardioverted (usually self terminated within 48 hours, often triggered in pulmonary veins). 2. Persistent AFib:- Episodes of AFib longer than 7 days, either self terminated or cardioverted. 
3. Long standing persistent AFib:- AFib lasting more than 1 year and rhythm control strategy is being adopted. 
4. Permanent AFib:- Episodes of AFib where no more rhythm strategy is adopted (i.e. as the rhythm is unresponsive). 

Presents with palpitations, SOB, syncope, and features of underlying conditions (e.g. stroke, sepsis, thyrotoxicosis). 

Causes:- 
1. Ischemic heart disease 
2. HTN 
3. Thyrotoxicosis 
4. Mitral stenosis or mitral regurgitation 
5. Alcohol 
6. OSA 

Diagnosis:- 
1. ECG shows absent P waves, irregularly irregular rhythm (i.e. irregular R-R interval), narrow QRS complex and tachycardia. 
2. Echocardiography (TEE or TTE) is done prior to cardioversion to prevent embolic stroke. 
3. Cardiac Monitor
4. EPS

Management:- 
1. Rate control:- Beta blockers (e.g. metoprolol, carvedilol, atenolol), non-dihydropyridine CCBs (e.g. verapamil, diltiazem) and Digoxin (in patients with CHF).
2. Rhythm control:- Pharmacological cardioversion (e.g. ibutilide, amiodarone, flecainide) or electrical cardioversion (DC 200J biphasic); It helps to return to sinus rhythm; Immediate cardioversion is deployed if the AFib has been present for less than 48 hours or the patient are hemodynamically unstable whereas delayed cardioversion is deployed if the AFib has been present for more than 48 hours and the patient are hemodynamically stable. 

What are the options for cardioversion for new-onset atrial fibrillation or atrial fibrillation of uncertain duration? 
· TEE prior to cardioversion while on effective anticoagulation with at least 4 weeks of therapeutic anticoagulation to follow (continue indefinitely if suggested by stroke risk).
· Alternatively, may therapeutically anticoagulate for at least 3 weeks prior to cardioversion and continue for at least 4 weeks afterwards, in lieu of TEE.

3. Anticoagulation:- Warfarin, DOACs (e.g. apixaban, rivaroxaban); CHA2DS2VASc is a clinical tool for prescribing anticoagulants in patients with nonvalvular atrial fibrillation; Congestive heart failure (1), Hypertension (1), Age ≥75 years (2), Diabetes (1), Stroke/TIA (2), Vascular disease e.g. previous myocardial infarction or peripheral arterial disease (1), Age 65-74 years (1), Sex category female (1). In non-valvular AFib, warfarin or Novel oral anticoagulants (NOACs) is indicated when CHA2DS2-VASc score ≥2 in men and ≥3 in women and should be considered CHA2DS2-VASc score >1 and >2 in men and women respectively. In valvular AFib, warfarin should be considered and targeted INR should be 2-3. 

4. Percutaneous ablation of pulmonary veins (i.e. pulmonary vein isolation) is first line for symptomatic paroxysmal atrial fibrillation. Catheter ablation for atrial fibrillation in patients with heart failure was associated with a significantly lower rate of a composite end point of death from any cause or hospitalization for worsening heart failure than was medical therapy (i.e. CASTLE HTx TRIAL).

5. Percutaneous left atrial appendage occlusion (if patients are contraindicated for long term anticoagulation therapy) i.e. Watchman, Watchman-FLX and Amlet devices. Percutaneous left atrial appendage occlusion is recommended in AF patients with a risk of stroke who have contraindications to long term anticoagulation. For high bleeding risk (HAS-BLED is greater than or equal to 3 if DOAC contraindicated.

6. Surgical ablation in patients with concomitant plan for cardiac surgery (e.g.maze procedure).
HAS-BLED score monitors a patient’s risk of major bleeding whilst on anticoagulation (i.e. Bleeding risk associated with anticoagulation); H - Hypertension, A - Abnormal renal and liver function, S - Stroke, B - Bleeding, L - Labile INRs (whilst on warfarin), E - Elderly, D - Drugs or alcohol; HAS-BLED score ≥ 3 (indicates high risk of bleeding).

Figure:- Management Guidelines of Atrial Fibrillation