Ablation of premature ventricular contractions utilizing QMODE+
Although vHPSD concepts have been evaluated for atrial procedures, data for ablation within the ventricles is very limited. Only one case report and one study for catheter ablation of PVC utilizing the QDOT MICROTM Catheter have been published in humans up to date.
In the initial case report a patient with frequent monomorphic PVC originating from the right ventricular (RV) outflow tract (OT) (RVOT) received three-dimensional electroanatomic reconstruction of the right ventricle. The earliest activation was detected within the antero-lateral RVOT. At this area the microelectrodes detected early fragmented potentials which were not detectable on the standard bipolar electrode of the ablation catheter. A single vHPSD application of 4 s was performed resulting in an immediate loss of PVC. No periprocedural complications occurred and no recurrent PVC was reported during long-term follow-up.
After successful performing the above-mentioned case a pilot study for PVC treatment via QDOT MICROTM Catheter was conducted. In the prospective single-center FAST and FURIOUS PVC study, we sought to investigate the efficacy, safety and clinical outcome of vHPSD ablation for the treatment of idiopathic PVCs originating from the right and left ventricular OTs. The data was compared to standard power-controlled ablation strategy using conventional contact-force sensing ablation catheters. In this study, twenty-four consecutive patients underwent PVC ablation utilizing vHPSD ablation (study group) and were compared with 24 consecutive patients previously treated with power-controlled ablation (control group). Each group included 12 patients with PVCs originating from the RVOT and 12 patients with PVCs originating from the left ventricular OT (LVOT). The acute endpoint of PVC elimination was achieved in all patients. In this study, vHPSD was used as the first approach and was switch to conventional QMODE after ineffectiveness. In 16/24 (67%) patients (study group) the acute endpoint was achieved by using vHPSD only (RVOT: 92%, LVOT 42%). The earliest activation found on the microelectrodes of the QDOT MICROTM Catheter was significantly earlier than on the standard bipolar electrodes. The median RF delivery time was massively reduced utilizing vHPSD (p<0.0001). No difference was observed regarding procedure duration (p=0.489), follow-up (p=0.712) and severe adverse events (4%, study group, 8%, control group, p=0.551).
Although the FAST and FURIOUS PVC study was a single center non-randomized study it demonstrated the feasibility and safety of the QDOT MICROTM Catheter for treatment of OVC originated from the RVOT and LVOT. In the thin walled RVOT the success rate of vHPSD was 92% while it was 42% for LVOT case. Therefore, it seems to be reasonable to consider vHPSD (QMODE+) for PVC originating from the RVOT (Figure 5 ) and conventional QMODE for PVC originating from the LVOT.