SAFE Combinations Fail to Open the Door to Atrial Fibrillation Prevention

The prevalence of atrial fibrillation (AF) in the entire US population is ≈1%.1 The prevalence of AF increases substantially with age, with ≤9% of patients over the age of 80 years developing AF. The population presenting with permanent pacing requirements also increases with age, and the cumulative lifetime risk of developing paroxysmal AF in pacemaker patients may be as high as 40%.2Article see p 687Mechanisms for AF initiation and maintenance are multiple but are widely accepted to be a result of triggered initiation by atrial premature beats, and maintenance within the atrial substrate on the basis of multiple wavelets of reentry and rotors that depend on inhomogeneous atrial refractory periods and atrial conduction velocities. Atrial pacing may prevent both AF triggers and atrial substrate changes by suppressing atrial premature beats and inducing a more homogenous atrial landscape of refractory periods and conduction velocities. Atrial-based pacing is clearly superior to ventricular pacing alone in preventing atrial fibrillation with an 18% relative risk reduction with atrial-based pacing over a 3-year follow-up.3 This treatment effect has been postulated to be the result of atrial premature beat suppression and changes in atrial refractory periods and atrial conduction velocities as a result of atrial stretch attributed to higher atrial pressure from AV dyssynchronous pacing. The atrial changes associated with atrial-based pacing could possibly be enhanced by atrial overdrive pacing algorithms or by alternative site atrial pacing, such as the atrial septum. The role of alternative-site atrial pacing …