ECG-Based Indices to Characterize Persistent Atrial Fibrillation Before and During Stepwise Catheter Ablation

Area of Science:

• Electrophysiology
• Cardiology
• Medical Imaging and Signal Processing

Background:

• Catheter ablation (CA) for persistent atrial fibrillation (pers-AF) has inconsistent success rates.
• Predicting patient response and monitoring ablation effectiveness requires improved methods.
• Electrocardiogram (ECG) analysis offers a noninvasive approach to assess atrial activity during procedures.

Purpose of the Study:

• To refine patient selection for CA based on ECG-derived atrial organization indices.
• To evaluate the temporal changes in AF organization during stepwise CA.
• To identify ECG markers indicating ablation effectiveness and potential for recurrence.

Main Methods:

• Continuous 12-lead ECG recordings during stepwise CA in 40 pers-AF patients.
• Analysis of ECG signals in 10-second epochs: pre-pulmonary vein isolation (PVI), during PVI, and post-PVI.
• Calculation of instantaneous frequency (IF), adaptive organization index (AOI), sample entropy (SampEn), and f-wave amplitude (FWA) to quantify AF organization.

Main Results:

• Patients were categorized into: left atrium terminated/not recurring (LTN), left atrium terminated/recurring (LTR), and not left atrium terminated/all recurring (NLT).
• The NLT group exhibited the lowest AF organization across all ablation stages.
• While AF organization generally increased post-ablation, specific ECG measure changes differed between AF and atrial tachycardia/atrial flutter recurrence types.

Conclusions:

• Noninvasive ECG measures reveal diminished AF organization in patients with poor response to stepwise CA.
• ECG analysis during CA does not predict recurrence but highlights poor responders.
• Increased atrial organization post-ablation may correlate with organized arrhythmia recurrence.