• Atrial fibrillation (AF) is a supraventricular arrhythmia characterized by uncoordinated atrial activation and consequent deterioration of mechanical function.
• AF is associated with a high risk of stroke as well as increased mortality and health expenditures; as such, it is a major public health issue.

• Cardiovascular: HTN, CAD, CHF, valvular (mitral stenosis), and pericardial heart disease
• Non-cardiovascular: DM, hyperthyroidism, alcohol abuse, COPD, age
• Iatrogenic: Surgery, medications (beta-agonists, cold medications, antihistamines, local anesthetics)
• Familial: Na⁺ and K⁺ channel mutations
• Perioperative: Atrial injury or ischemic inflammation, increased adrenergic tone, atrial stretch from volume overload, and electrolyte disturbances

• Re-entry is the main electrophysiologic mechanism of AF, and is secondary to structural or electrical remodeling.
• Atrial dilation and inflammation can result in interstitial fibrosis and is the most common substrate predisposing to AF.
• Channelopathies involving both K⁺ and Na⁺ channels are responsible for most familial forms of AF.
• Triggers include alcohol, sleep deprivation, emotional stress, caffeine, and exercise.

• Maintain rate control in patients presenting with AF; maintain NSR in patients with recurrent or paroxysmal AF.
• Perioperative anticoagulation strategy should balance the risk of bleeding related to the type of surgery and the individual patient's risk of thrombosis (3) [B].
• Optimization of comorbidities
• Implement preventative strategies in surgical patients who are at a high risk for the development of AF (e.g., thoracic and cardiac procedures).

• Palpitations, shortness of breath
• Neurologic symptoms

• Length of treatment
• Antiarrhythmics: Class, efficacy, side effects
• Previous electrical cardioversion
• Electrophysiological ablation
• Percutaneous closure of the left atrial appendix
• Anticoagulation regimen; INR if on warfarin

• for rhythm control, Class III antiarrhythmics (amiodarone, sotalol) are preferred due to their decreased toxicity, however they should be used with caution in patients with LQT. for rate control, beta-blockers, calcium channel blockers, and digitalis are commonly used.
• Amiodarone is effective for both rate control and pharmacological cardioversion (up to 90% success if bolused followed by infusion). It is considered safe in patients with LV dysfunction, unlike class I_C drugs. Acute side effects: Hypotension, bradycardia.
• CHADS2 provides an objective score for estimating the risk of stroke in non-valvular AF. Points for individual stroke risk factors are assigned as follows: 1 point is assigned for CHF, HTN, age >75, or DM; and 2 points are assigned for a history of CVA/TIA. A CHADS2 score of 0 denotes low risk, 1–2 intermediate risk, and 3–6 high risk of stroke (4) [A].
• Anticoagulation regimens are based upon the risk of stroke (CHADS2 or other scores) and are balanced against the risk of bleeding.
  • Aspirin if CHADS2 score 1
  • Warfarin if CHADS2 score 2
  • Dabigatran is a direct selective thrombin inhibitor. Stroke prevention is equal to that of warfarin and fewer bleeding complications are seen with low doses. It is dosed twice per day, orally. for a CHADS2 score = 1, the dose is 110 mg PO and for a CHADS2 score 2, the dose is 150 mg PO (4) [A].
  • The CHADS2 score has not been validated in valvular AF where there is a high risk of stroke; thus, anticoagulation is always required.
• Statins

• Palpation or auscultation: Irregular heart rate
• EKG: Uneven R-R interval with occasional f waves
• CXR: Pulmonary vasculature congestion and cardiomegaly
• Echocardiogram and stress testing may be considered to rule out underlying structural or ischemic myocardial disease, left atrial enlargement, thrombus, RV strain if PE is suspected.
• Holter monitor in suspected paroxysmal AF or if evaluating the efficacy of rate control treatment
• Pacemaker may be in place.

Evaluate cardiopulmonary, neurologic, and endocrine systems for known associated comorbidities

• Poor rate control
• Signs and symptoms of CHF
• New-onset AF of unknown etiology (rule out ischemic or structural heart disease)
• Delay DC cardioversion until therapeutic INR or TEE evidence of atrial thrombus

• Newly discovered AF is the first presentation of AF for which the actual onset is not known.
• Paroxysmal and persistent AFs are both recurrent, but the former is self-terminating within 7 days, while the latter requires cardioversion to restore sinus rhythm.
• Permanent AF describes unsuccessful or abandoned attempts to convert to sinus rhythm.
• Etiologically, AF can be valvular or non-valvular. Patients with mitral valve disease are at an increased risk for stroke.

• Routine postoperative care is usually appropriate in stable patients.
• Telemetry or ICU care may be warranted in poorly controlled AF and hemodynamic instability.

• Reinstitute rate control, antiarrhythmic, and/or anticoagulants as soon as appropriate
• Labs: Electrolytes, glucose in DM, INR/PTT
• Troponins if underlying cause for AF is CAD

• RVR with hypotension, CHF
• Ventricular arrhythmias
• Myocardial ischemia
• Bleeding versus stroke and other thrombotic complications
• Postoperative cognitive dysfunction

• Atrial Flutter
• Cerebrovascular Disease
• Postoperative Stroke
• Perioperative Statins

427.31 Atrial fibrillation

• I48.0 Paroxysmal atrial fibrillation
• I48.2 Chronic atrial fibrillation
• I48.91 Unspecified atrial fibrillation

andrea Vanucci , MD, DEAA

Ivan M. Kangrga , MD, PhD