Atrial fibrillation: established and innovative methods of evaluation and treatment

Abstract

Background: 5% to 8% of 70-year-olds and some 10% of persons over age 80 have atrial fibrillation (AF).

Methods: Selective literature review.

Results: New scoring schemes (CHA(2)DS(2)-VASc score, HAS-BLED score) have been introduced to enable more accurate estimation of the risk of stroke and hemorrhage in patients with AF. These scores are calculated on the basis of clinical data (left ventricular dysfunction, hypertension, age, diabetes, prior stroke, vascular diseases, sex, renal or hepatic dysfunction, bleeding, labile INR values, consumption of medications and alcohol) and are used to determine the potential indication for, and appropriate type of, anticoagulation in the individual AF patient. Hemodynamically unstable patients with rapid AF should undergo DC cardioversion at once. Patients with permanent AF should be given beta-blockers, calcium antagonists, or digitalis for rate control, with a target rate below 110/minute. A recently introduced drug, dronedarone, is used for rhythm control and has relatively few side effects. Patients with AF and impaired left ventricular function should be given amiodarone. Rhythm control has not been found to prolong life any more than rate control. Patients with a CHA(2)DS(2)-VASc score of 2 or above should be orally anticoagulated. Those with a score of 1 can be treated with aspirin (75 to 325 mg daily); those with a score of 0 do not need antithrombotic treatment. A HAS-BLED score of 3 or above is associated with a high risk of bleeding. Pulmonary vein isolation is an established method of treating symptomatic AF, with a success rate of 60% to 80%. Surgical procedures are possible in AF patients who need additional cardiac surgery.

Conclusion: The treatment strategy for AF must be individualized on the basis of the patient's clinical manifestations. The mainstay of treatment is anticoagulation; the indication for anticoagulation depends on the patient's age, underlying disease, and left ventricular function.

Figure 1

Intracardiac recordings before pulmonary vein isolation. The observed potentials (electrograms) from the pulmonary veins serve as triggers for the initiation of atrial fibrillation. They are the target potentials in pulmonary vein isolation: The goal of ablation in the treatment of atrial fibrillation is to eliminate them entirely. The absence of these potentials is taken to indicate successful ablation

Figure 2

Intracardiac recordings after pulmonary vein isolation. Total isolation of the pulmonary veins by interruption of the conducting pathways from the pulmonary veins to the left atrium (entrance block after ablation). The pulmonary vein electrograms that were seen before ablation (Figure 1) are no longer present; thus, pulmonary vein isolation is likely to be successful in this case. Pulmonary vein isolation is now an established technique, with success rates above 70% LSPV, left superior pulmonary vein