Atrial Fibrillation Inducibility in the Absence of Structural Heart Disease or Clinical Atrial Fibrillation

Background—Inducibility of atrial fibrillation (AF) after pulmonary vein isolation has been used to guide additional left atrial ablation in paroxysmal AF. The sensitivity and specificity of AF induction in this setting remains uncertain. We examined the incidence and characteristics of inducible AF in patients without structural heart disease or clinical AF and the effect of different induction protocols on AF inducibility. Methods and Results—In 44 patients with supraventricular tachycardia with no history of AF or risk factors for AF, atrial refractoriness and conduction were measured, followed by AF induction attempts (10/patient). Each induction was performed after a waiting time that exceeded twice the duration of induced AF from the preceding induction. AF ≥1 minute was considered inducible, and ≥5 minutes as sustained. Burst pacing (at 200 ms for 10 seconds) was compared to decremental pacing (from 200 ms to shortest cycle length, resulting in 1:1 atrial capture for 10 seconds). After 10 induction...