Atrial Pacing for the Prevention and Termination of Atrial Fibrillation

Abstract

Atrial fibrillation (AF) affects about 2% of the general population and 8%-11% of those older than 65 years. The demand for effective therapeutic strategies for AF is anticipated to increase substantially as the proportion of the elderly population increases. Atrioventricular nodal ablation accompanied by permanent pacemaker implantation is an established option in elderly patients with intractable arrhythmia and poor ventricular rate control. However, it renders most patients pacemaker dependent and does not eliminate symptoms associated with loss of atrial transport or reduce the risk of stroke. The considerable limitations of rhythm or rate control strategies prompted interest in preventative atrial pacing, which may reduce the incidence of AF by either eliminating the triggers and/or by modifying the substrate of AF. Atrial or dual-chamber pacing has been proven to prevent or delay progression to permanent AF in elderly patients with sinus node dysfunction as compared with ventricular pacing. Patients with advanced atrial conduction delay may benefit from atrial resynchronization pacing. There may be additional benefits associated with the use of particular sites of pacing, specific pacing algorithms designed to target potential triggers of AF, and pace-termination of atrial tachycardia. Preventive and antitachycardia pacing algorithms incorporated in implantable cardioverter-defibrillators and pacemakers are currently under investigation and may offer a valuable alternative to antiarrhythmic drug therapy in elderly patients with left ventricular dysfunction at high risk of proarrhythmia or worsening heart failure. The evolution of hybrid therapy, in which two or more different strategies are employed in the same patient, may be the most effective approach to management of AF.

Supraventricular Arrhythmias: An Electrophysiology Primer

“…However, AV nodal ablation results in complete heart block and subsequently necessitates the implantation of a permanent pacemaker. It is important to recognize that this treatment option does not eliminate the symptoms associated with the loss of atrial output (atrial kick), nor the risk of stroke 4 . Thus the patient must remain on anticoagulation therapy since his/her underlying rhythm (beneath the paced rhythm) remains AF.…”

“…Preventive atrial pacing therapy is currently being investigated as a strategy to reduce the incidence of AF by either elimination of the triggers and/or modification of the substrate of AF. In comparison to ventricular pacing, atrial or dual‐chamber pacing has been shown to prevent or delay progression to permanent AF in elderly patients 4 . Atrial resynchronization pacing is being studied in the treatment of patients with advanced atrial conduction delay.…”

“…The use of hybrid therapy consisting of two or more treatment strategies may help reduce morbidity and mortality of AF. In elderly patients and those with heart failure, proarrhythmia risks from antiarrhythmic drug therapy may be reduced or eliminated with preventive antitachycardia pacing 4 …”

“…Elderly patients and those with heart failure have a greater risk of developing proarrhythmia from antiarrhythmic drug therapy 4 . The risk of proarrhythmia is greatest in the first 24–48 hours after initiating the drug, and pausedependent torsades de pointes may occur after conversion to sinus rhythm 23 .…”

“…Although ventricular arrhythmias and implantable cardioverter‐defibrillators have garnered the spotlight in the field of cardiovascular electrophysiology, supraventricular tachycardias (SVTs) continue to be the most prevalent arrhythmias, with atrial fibrillation (AF) remaining the most common cardiac arrhythmia, 1–3 affecting 2% of the general population 4 . As the population ages, the incidence of AF continues to increase, 2,3 affecting 8%–11% of people over 65 years of age 4 . Eighty‐four percent of patients with AF are over 65 years (median age, 75 years), 5 and the prevalence of AF is expected to double over the next 50 years 6–8 …”