An Increase in Right Atrial Magnetic Strength Is a Novel Predictor of Recurrence of Atrial Fibrillation After Radiofrequency Catheter Ablation

Abstract

Background: Differences in electrical properties between left and right atria (LA and RA) after pulmonary vein isolation (PVI) for atrial fibrillation (AF) are currently poorly understood. Magnetocardiograms were used to investigate the effect of PVI on bi-atrial magnetic field changes and their relationship to clinical outcomes. Methods and Results:This study included 71 patients undergoing PVI for paroxysmal AF. Magnetocardiograms were recorded at baseline and 1 day, 8 weeks, and 24 weeks after ablation. Peak magnitude of LA and RA segments on P waves was separately compared before and after PVI. During a 16-month post-ablation period, 53 (75%) patients were free from AF recurrences. LA magnetic strength in patients without recurrence persistently decreased for 24 weeks and was significantly lower at 8 weeks than that in patients with recurrence (1.28±0.69 vs. 1.74±0.71 pico-Tesla, P=0.02). RA magnetic strength in patients with recurrence persistently rose for 24 weeks and was significantly higher at 8 weeks than that in patients without recurrence (2.17±0.82 vs. 3.00±1.12 pico-Tesla, P=0.001). Multivariate analysis showed RA magnetic strength at 8 weeks to be the strongest predictor of AF recurrence (odds ratio=3.335; 95% confidence interval=1.181-9.416; P=0.02). Conclusions Methods Study SubjectsThe subjects of this study comprised 71 consecutive patients who underwent only antral PVI for treatment of paroxysmal AF. Clinical characteristics of the patients are shown in Table 1.Patients with structural heart disease or who had undergone a prior ablation procedure for AF were excluded from this study. Electrophysiologic Study and Catheter AblationThe study protocol was approved by the local Institutional Review Board, and all patients provided their informed written consent. All antiarrhythmic drug therapy was discontinued 4-5 half-lives before the procedure except for amiodarone, which was discontinued 8 weeks beforehand. A 7F 14-pole dual-site mapping catheter (Irvine Biomedical Inc, Irvin, CA, USA) was positioned in the coronary sinus and the low lateral wall of the RA throughout the procedure. Three long sheaths (SL0, AF Division, St. Jude Medical, Minnetonka, MN, USA) were then advanced into the LA, and LA pressure was measured just after transseptal puncture using a long sheath connected to a pressure transducer (TruWave, Edwards Lifesciences, Irvine, CA, USA). Following PV angiography, 2 decapolar ring catheters (Lasso, Biosense Webster, Diamond Bar, CA, USA) were placed in the superior and inferior PVs on one side at a time. An open-irrigation, 3.5-mm-tip deflectable catheter (ThermoCool, Biosense Webster) was used for mapping and ablation. Bipolar electrograms were displayed and recorded at filter settings of 30 to 500 Hz during the procedure (CardioLab System, Pruka Engineering, Houston, TX, USA). The LA and PVs were constructed with a 3-dimensional electro-anatomic mapping system (CARTO, Biosense Webster), and an activation map during sinus rhythm was depicted before ablation. The ipsilateral PV an...

Electrophysiological mechanisms of long and short QT syndromes

“…It was proposed that the term QRS d /QRS could be a surrogate marker of CV dispersion coefficient based on the standard deviation of the mean CV [68]. Other non-invasive methods of assessing the function of the heart include magnetocardiography, which may provide additional insights into risk stratification in the future [69], [70], [71], [72], [73], [74], [75], [76].…”

Ipsilateral Circumferential Radiofrequency Ablation of Atrial Fibrillation With Irrigated Tip Catheter

“…The outcome for NPAF (36%) was less satisfactory but still better than after ostial PVI as determined by Weerasooriya et al 20 Predictors of Very Late Recurrence After Circumferential Ablation of AF Many factors (type of AF, LA size, age, sleep apnea and obesity, hypertension, LA fibrosis detected on magnetic resonance imaging [MRI], diabetes, rise in right atrium magnetic strength) have been proposed as predictors of poorer outcome after PVI. 19, 30 The most consistent predictor of very late recurrence was type of AF, followed by LA size. 19 We found that the independent predictors of very late recurrence of AF after circumferential RF ablation were: type of AF, size of LA, and impairment of renal function.…”

Cryoballoon ablation of atrial fibrillation: How important is the proper selection of patients?

“…Many factors (type of AF, LA size, age, sleep apnea and obesity, hypertension, LA fibrosis detected by magnetic resonance imaging, diabetes, a rise in right atrium magnetic strength) have been proposed as predictors of a poorer outcome after PVI [18,19] but the discrepancies among authors [20][21][22][23][24][25] showed the complicated nature of already ablated atrial tissue. We applied a combined ALARMEc risk score which effectively discriminates patient outcome after any ablation procedure [4,5].…”