Background and aims: Discrete potentials, low voltage and fragmented electrograms, have been previously reported at ablation site, in patients with premature ventricular contractions (PVCs) originating in the right ventricular outflow tract (RVOT). The aim of this study was to review the electrograms at ablation site and assess the presence of diastolic potentials and their association with success.
Methods: We retrospectively reviewed the electrograms obtained at the radiofrequency (RF) delivery sites of 48 patients subjected to ablation of RVOT frequent PVCs. We assessed the duration and amplitude of local electrogram, local activation time, and presence of diastolic potentials and fragmented electrograms.
Results: We reviewed 134 electrograms, median 2 (1-4) per patient. Success was achieved in 40 patients (83%). At successful sites the local activation time was earlier- 54 (-35 to -77) ms vs -26 (-12 to -35) ms, p<0.0001; the local electrogram had lower amplitude 1 (0.45-1.15) vs 1.5 (0.5-2.1) mV, p = 0.006, and longer duration 106 (80-154) vs 74 (60-90) ms, p<0.0001. Diastolic potentials and fragmented electrograms were more frequently present, respectively 76% vs 9%, p <0.0001 and 54% vs 11%, p<0.0001. In univariable analysis these variables were all associated with success. In multivariable analysis only the presence of diastolic potentials [OR 15.5 (95% CI: 3.92-61.2; p<0.0001)], and the value of local activation time [OR 1.11 (95% CI: 1.049-1.172 p<0.0001)], were significantly associated with success.
Conclusion: In this group of patients the presence of diastolic potentials at the ablation site was associated with success.