Automatic identification of ablation targets in persistent atrial fibrillation: Initial experience with a new mapping tool.

INTRODUCTION: Strategies beyond pulmonary vein isolation (PVI) in persistent atrial fibrillation (persAF) are debated. A novel mapping tool provides algorithmic detection of ablation targets based on electrogram (EGM) properties specific to stable localized rotational activations. METHODS: The mapping tool was used on 31 patients (20 de novo). The algorithm was used to optimize PVI line placement and guide additional ablations. Targets were detected by calculating local cycle length (L-CL) and local spread of activation within that L-CL (Duty Cycle; DC) for EGMs with consistent morphology and activation. At least two left atrial (LA) maps (pre-PVI and post-PVI) were acquired in atrial fibrillation (AF) in all patients (except those with AF termination during PVI). Extra-pulmonary vein (PV) targets were compared between the two LA maps in each patient. Follow-up included Holter monitoring every 3 months. RESULTS: Patients had a median of 3 extra-PV drivers/targets. The majority (81%) were localized in the same areas between the two LA maps. All patients had progressive AF organization demonstrated by global activation slowing: histogram peak L-CL increased from 162 to 171 ms (post-PVI; p = .0003) than to 175 ms (posttarget ablation; p = .04). Moreover, L-CL dispersion was reduced by ablation; in 50% their values tended to cluster around two dominant cycles. In de novo patients AF terminated to sinus rhythm or atrial tachycardia (AT) within 48 h postprocedure in 88% of cases, and at 18 months mean follow-up recurrence occurred in only five (25%) patients (three persAF, two AT). There were no complications. CONCLUSION: The algorithmic detection of EGMs consistent with localized reentry during sequential mapping of persAF provided reproducible targets for ablation. This allowed personalized PVI and limited, highly-selective, extra-PV ablation. Results of this initial experience included progressive organization of AF with ablation and a low recurrence rate after a single procedure.

Galectin-3 level predicts response to ablation and outcomes in patients with persistent atrial fibrillation and systolic heart failure.

INTRODUCTION: Mechanisms of maintenance of both atrial fibrillation and structural left ventricular disease are known to include fibrosis. Galectin-3, a biomarker of fibrosis, is elevated both in patients with heart failure and persistent atrial fibrillation. We sought to find whether galectin-3 has a prognostic value in patients with heart failure and a reduced left ventricular ejection fraction undergoing ablation of persistent atrial fibrillation. METHODS: Serum concentrations of galectin-3 were determined in a consecutive series of patients with an ejection fraction ≤40%, addressed for ablation of persistent atrial fibrillation. Responders to ablation were patients in sinus rhythm and with an ejection fraction ≥50% at 6 months. A combined endpoint of heart failure hospitalization, transplantation and/or death was used at 12 months. RESULTS: Seventy-five patients were included (81% male, age 63±10 years, ejection fraction 34±7%, galectin-3 21±12 ng/mL). During follow-up, eight patients were hospitalized for decompensated heart failure, 1 underwent heart transplantation, and 4 died; 50 patients were considered as responders to ablation. After adjustment, galectin-3 level independently predicted both 6-month absence of response to ablation (OR = 0.89 per unit increase, p = 0.002). Patients with galectin-3 levels <26 had a 95% 1-year event-free survival versus 46% in patients with galectin-3 ≥26 ng/mL (p<0.0001). CONCLUSIONS: Galectin-3 levels independently predict outcomes in patients with reduced left ventricular systolic function addressed for ablation of persistent AF, and may be of interest in defining the therapeutic strategy in this population.

Three-dimensional interlead distance predicts response and outcomes after cardiac resynchronization therapy.

BACKGROUND: Approximately one-third of patients do not respond favourably to cardiac resynchronization therapy (CRT). A longer distance between ventricular leads may improve response. AIM: To study the impact of the true three-dimensional interlead distance (ILD) on outcomes. METHODS: Consecutive patients undergoing CRT device implantation were included prospectively. Interlead separation was measured from postprocedural anterior-posterior and lateral chest X-rays. The three-dimensional ILD was calculated using the Pythagorean theorem. Response to CRT was defined using a composite clinical score at 6 months. RESULTS: Forty-two patients were included (mean age 70±9 years; QRS duration 154±31ms; left ventricular ejection fraction 26±7%; 50% ischaemic). At 6 months, 71% of patients were considered to be responders. Responders had a significantly longer ILD (108±17 vs. 87±21mm; P=0.002). When the ILD was corrected for cardiac size, the optimal cut-off value was ≥ 0.53 for predicting response (sensitivity 83%, specificity 75%, area under the curve 0.84; P=0.0002). Similar results were obtained in a historical retrospective cohort. The use of proximal electrodes on the left ventricular lead was associated with a longer ILD in 95% of patients, compared with more distal pacing configurations. In the total cohort of 74 patients (median follow-up, 420 days), those with an indexed ILD ≥ 0.53 had a 70% reduction in risk of hospitalization for heart failure (P=0.004). CONCLUSION: Longer three-dimensional ILD corrected for cardiac size measured on chest radiographs can accurately predict response to CRT and outcomes. This simple variable may be used to identify optimal lead placement and pacing configuration during CRT implantation.

Serum Galectin-3 Levels Predict Recurrences after Ablation of Atrial Fibrillation.

Galectin-3 is a biomarker of fibrosis and atrial remodeling, involved in the mechanisms of initiation and maintenance of atrial fibrillation (AF). We sought to study the accuracy of galectin-3 level in predicting recurrences of AF after ablation. Serum concentrations of galectin-3 were determined in a consecutive series of patients addressed for AF ablation in our center. After a 3-month blanking period, recurrences of atrial arrhythmias were collected during the first year in all patients, using Holter monitoring at 3, 6 months and 12 months. A total of 160 patients were included, with a mean galectin-3 rate was 14.4 ± 5.6 ng/mL. At 12-month, 55 patients (34%) had reexperienced sustained atrial arrhythmia. Only higher galectin-3 level (HR = 1.07 [1.01-1.12], p = 0.02) and larger left atrial diameter (HR = 1.07 [1.03-1.12], p = 0.001) independently predicted recurrence. Patients with both galectin-3 level <15 ng/mL and left atrial diameter <40 millimeters had a 1-year arrhythmia-free survival rate - after a single procedure without anti-arrhythmic drug - of 91%, as compared with 41% in patients with galectin-3 ≥ 15 and left trial diameter ≥40 (p < 0.0001), whether AF was paroxysmal or persistent. Galectin-3 and left atrial diameters, rather than clinical presentation of AF, predict recurrences after ablation.

Mortality After Atrioventricular Nodal Radiofrequency Catheter Ablation With Permanent Ventricular Pacing in Atrial Fibrillation: Outcomes From a Controlled Nonrandomized Study.

BACKGROUND: Atrioventricular nodal radiofrequency ablation (AVNA) with permanent ventricular pacing can be used to control rate in patients with atrial fibrillation (AF). However, long-term outcomes after AVNA are uncertain, especially in light of irreversible pacemaker dependence. METHODS AND RESULTS: We examined 9122 consecutive patients with AF. The outcomes in 453 patients with AVNA (26% of whom underwent an implantable cardiac defibrillator implant and 37% underwent cardiac resynchronization therapy implant) were compared with AF patients without AVNA after propensity score 1:1 matching. During follow-up in the propensity-matched cohort (2.41±3.23 years, median 1.23, quartiles 0.33-3.12), 100 patients died (yearly rate of death 6.6%). Mode of death was available in 86% of patients, which was cardiovascular in 67% of the patients (related to heart failure in 38%, sudden death in 5%, and other cardiovascular reason in 24%) and noncardiovascular in 33%. AVNA in patients with AF was associated with a lower risk of mortality (odds ratio 0.47, 95% confidence interval, 0.29-0.77; P=0.003), a lower risk of cardiovascular mortality (odds ratio =0.41, 95% confidence interval 0.23-0.73; P=0.003), and nonsignificant lower risk of stroke and thromboembolic events (odds ratio =0.61, 95% confidence interval 0.36-1.06; P=0.08). CONCLUSIONS: In sick AF patients with multiple comorbidities, AVNA with permanent ventricular pacing for rate control seems safe during follow-up and may be associated with lower mortality.