Noninvasive Assessment of Complexity of Atrial Fibrillation: Correlation With Contact Mapping and Impact of Ablation.

BACKGROUND: It is difficult to noninvasively phenotype atrial fibrillation (AF) in a way that reflects clinical end points such as response to therapy. We set out to map electrical patterns of disorganization and regions of reentrant activity in AF from the body surface using electrocardiographic imaging, calibrated to panoramic intracardiac recordings and referenced to AF termination by ablation. METHODS: Bi-atrial intracardiac electrograms of 47 patients with AF at ablation (30 persistent, 29 male, 63±9 years) were recorded with 64-pole basket catheters and simultaneous 57-lead body surface ECGs. Atrial epicardial electrical activity was reconstructed and organized sites were invasively and noninvasively tracked in 3-dimension using phase singularity. In a subset of 17 patients, sites of AF organization were targeted for ablation. RESULTS: Body surface mapping showed greater AF organization near intracardially detected drivers than elsewhere, both in phase singularity density (2.3±2.1 versus 1.9±1.6; P=0.02) and number of drivers (3.2±2.3 versus 2.7±1.7; P=0.02). Complexity, defined as the number of stable AF reentrant sites, was concordant between noninvasive and invasive methods (r2=0.5; CC=0.71). In the subset receiving targeted ablation, AF complexity showed lower values in those in whom AF terminated than those in whom AF did not terminate (P<0.01). CONCLUSIONS: AF complexity tracked noninvasively correlates well with organized and disorganized regions detected by panoramic intracardiac mapping and correlates with the acute outcome by ablation. This approach may assist in bedside monitoring of therapy or in improving the efficacy of ongoing ablation procedures.

Cost effectiveness of focal impulse and rotor modulation guided ablation added to pulmonary vein isolation for atrial fibrillation.

BACKGROUND: Although ablation with focal impulse and rotor modulation (FIRM), as an adjunct to pulmonary vein isolation (PVI), has been shown to decrease atrial fibrillation (AF) recurrence, cost-effectiveness has not been assessed. OBJECTIVE: We aimed to evaluate the cost effectiveness of FIRM-guided ablation when added to PVI in a mixed AF population. METHODS AND RESULTS: We used a Markov model to estimate the costs, quality-adjusted survival, and cost effectiveness of adding FIRM ablation to PVI. AF recurrence rates were based on 3-year data from the CONFIRM trial. Model inputs for event probabilities and utilities were obtained from literature review. Costs were based on Medicare reimbursement, wholesale acquisition costs, and literature review. Three-year total costs FIRM+PVI versus PVI alone were $27,686 versus $26,924. QALYs were 2.338 versus 2.316, respectively, resulting in an incremental cost-effectiveness ratio (ICER) of $34,452 per QALY gained. Most of the cost (65-81%) was related to the index ablation procedure. Lower AF recurrence generated cost offsets of $4,266, primarily due to a reduced need for medications and repeat ablation. Probabilistic sensitivity analysis demonstrated ICER below $100,000/QALY in 74% of simulations. CONCLUSION: Based on data from the CONFIRM study, the addition of FIRM to PVI does have the potential to be cost-effective due to higher quality-adjusted life years and lower follow-up costs. Value is sensitive to the incremental reduction in AF recurrence, and FIRM may have the greatest economic value in patients with greater AF symptom severity. Results from ongoing randomized trials will provide further clarity.