  Catheter ablation (CA) is a commonly used treatment for persistent atrial
fibrillation (AF). Since its medium/long-term success rate remains limited,
preoperative prediction of its outcome is gaining clinical interest to
optimally select candidates for the procedure. Among predictors based on the
surface electrocardiogram, the dominant frequency (DF) and harmonic exponential
decay (g) of the fibrillatory waves ( f -waves) have reported promising but
clinically insufficient results. Hence, the main goal of this work was to
conduct a broader analysis of the f -wave harmonic spectral structure to
improve CA outcome prediction through several entropy-based measures computed
on different frequency bands. On a database of 151 persistent AF patients under
radio-frequency CA and a follow-up of 9 months, the newly introduced parameters
discriminated between patients who relapsed to AF and those who maintained SR
at about 70%, which was statistically superior to the DF and approximately
similar to g. They also provided complementary information to g through
different combinations in multivariate models based on lineal discriminant
analysis and report classification performance improvement of about 5%. These
results suggest that the presence of larger harmonics and a proportionally
smaller DF peak is associated with a decreased probability of AF recurrence
after CA.
