Predictors and Characteristics of Atrial Fibrillation Induced During Supraventricular Tachycardia Ablation Procedures

Abstract Introduction: Atrial fibrillation (Afib) inducibility during electrophysiological study (EPS) has been examined as an electrophysiological parameter, atrial vulnerability, related to clinical occurrence and recurrence of AF in many studies. However, the majority of these studies examined Afib induced in patients with paroxysmal supraventricular tachycardia (PSVT) who had clinically documented Afib prior to SVT ablation procedure. Aim of Study: The purpose of this study was to determine the prevalence, predictors and charactaristics of Afib induced during PSVT ablation procedures. Patients and Methods: Clinical and procedural data of all consecutive patients who underwent catheter ablation for PSVT from 2009 to 2015 were reviewed retrospectively. Results: The study group included 347 studies (median age 39 years, 40.1% male), the PSVT type was AVNRT in 50.1% of patients, AVRT in 43.8% and AT in 5.2%. Afib was documented in 76 studies (21.9%). Patients with induced Afib were younger, more males, taller and had shorter tachycardia cycle length (TCL). Afib was induced more frequently in AVRT patients (61.3%) then AVNRT (34.7%) and AT (4%). In multivariate analysis, TCL and tall stature were the sole independent predictors for induction of Afib among other predictors that included age, gender and type of the tachycardia (Nagelkerke R square = 0.124 and p<.0001). The induction of Afib was associated with significantly longer study duration especially in AVRT utilizing a left lateral AP. Ablation of the primary PSVT was found to significantly minimizes Afib episodes (p<0.0001). The total number of Afib episodes were 153 episodes. Pacing induced Afib was the most prevalent mode of initiation (41.2%) followed by degeneration of PSVT (30.1%), catheter induced (15.7%) and spontaneously induced (13.1%). Spontaneous termination (55.6%) was the most prevalent mode of termination followed by DC shock (25.5.2%), organization to PSVT (19%) with a higher percent-age of males among patients who had DC shocks. Conclusions: The prevalence of Afib induced during PSVT ablation is 21.9%. Induced Afib was found to signifi-cantly prolong PSVT ablation procedure times. Short TCL and tall stature were independent predictor for Afib inducibility.
Understanding the characteristics of initiation and termination may help to reduce the frequency of induced Afib.