Patient characteristics
Of 51 patients (27 male, 52.4±17.1 years) without structural heart disease who underwent catheter ablation of focal PVCs originating from the OT in 2018-2020, 15 cases had LVOT origins and 4 of those patients had PVCs with a fractionated presystolic potentials during the PVCs and late potentials during SR recorded at the successful ablation site. We reviewed these 4 cases using coherent activation maps.
Mapping and ablation were performed using a 3.5-mm-tip catheter (ThermoCool SF; Biosense Webster, Diamond Bar, CA, USA). Coherent activation mapping with the conduction velocity vector during the PVCs was created with the use of an electroanatomic mapping system (CARTO3 system V7, Biosense Webster) with bipolar electrograms, high pass filtered at 20 to 30 Hz and low pass filtered at 400 Hz. If the presystolic potential was seen, the presystolic potential was manually annotated to its onset. With the use of the mapping points for the PVC, the coherent SR activation map was also created by manual annotation to the offset of the electrograms during the SR beat preceding the PVCs. The late potential was also annotated to its offset. The twelve-lead electrocardiograms and bipolar intracardiac electrograms were recorded with a band pass filter of 30 to 500 Hz at paper speeds of 100 to 200 mm/s and stored on a digital recording system (LabSystem PRO, Bard Electrophysiology, Lowell, MA).