Objective: The mechanism underlying recurrence after successful ablation of ventricular arrhythmias (VAs) was unclear. Spectrum analysis can help to identify near-field activation. The purpose of this study was to quantify the changes of near-field activation in response to ablation at the VAs origin in the aortic root (AR-VAs) and to assess its relationship with late ablation outcome.
Methods and results: Patients who underwent acutely successful ablation for AR-VAs were analysed. Ventricular electrograms acquired before and after ablation at VAs origin were subjected to spectrum analysis. The area under the curve of the high frequency component (HFC, 50-200 Hz) and the low frequency component (LFC, 0-50 Hz) was measured. The proportion of HFC to the frequency spectrum of 0-200 Hz was defined as the HFC ratio (HFCR). The reduction of HFC and HFCR in response to ablation was defined as HFC pre-post and HFCR pre-post, respectively. Documentation of VAs with the same morphology after an acute successful procedure was defined as recurrence. Fifty-six patients were analysed, and VAs recurred in 17 patients. HFCR pre-post, HFC pre-post, and HFC pre-ablation were significantly higher in patients without recurrence. And HFCR pre-post has the highest predictive value (area under the receiver-operating characteristic curve: 0.975). A HFCR pre-post of 1.0% differentiated two groups (sensitivity = 84.6%, specificity = 100%). Higher HFCR pre-post was correlated with shorter VAs termination time (correlation coefficient = -0.399, p = .009).
Conclusions: HFCR pre-post can quantify the near-field activation change during ablation. Incomplete destruction to the VAs foci could underlie recurrence after successful ablation.
Keywords: Fourier analysis; Ventricular arrhythmia; catheter ablation.