RESUMO
Background: Pulmonary vein isolation (PVI) ablation is the established gold standard therapy for patients with symptomatic drug refractory atrial fibrillation (AF). Advancements in radiofrequency (RF) ablation, have led to the development of the novel contact force-sensing temperature-controlled very high-power short-duration (vHPSD) RF ablation. This setting delivers 90 W for up to 4 seconds with a constant irrigation flow rate of 8 mL/min. The aim of this study was to compare procedural outcomes and safety with conventional radiofrequency ablation. Methods: An observational study was conducted with patients who underwent first time PVI ablation between August 2020 and January 2022. The cohort was divided into: (1) vHPSD ablation; (2) High-power short duration (HPSD) ablation; (3) THERMOCOOL SMARTTOUCH™ SF (STSF). The vHPSD ablation group was prospectively recruited while the HPSD and STSF group were retrospectively collected. Primary outcomes were procedural success, PVI duration, ablation duration and incidence of perioperative adverse events. Secondary outcomes were intraprocedural morphine and midazolam requirement. Results: A total of 175 patients were included in the study with 100, 30 and 45 patients in the vHPSD, HPSD and STSF group, respectively. PVI was successfully attained in all vHPSD patients. vHPSD demonstrated significantly reduced time required for PVI and total energy application in comparison to the HPSD and STSF groups (67.7 ± 29.7 vs. 92.9 ± 25.7 vs. 93.6 ± 29.1 min, p < 0.0001; 9.87 ± 4.16 vs. 33.9 ± 7.49 vs. 36.0 ± 10.5 min, p < 0.0001, respectively). Intravenous morphine and midazolam requirement was lower in the vHPSD group compared to the HPSD and STSF groups (10.2 ± 3.43 vs. 16.1 ± 4.58 vs. 15.3 ± 3.94 mg, p < 0.0001; 4.04 ± 3.24 vs. 8.63 ± 5.22 vs. 8.58 ± 4.72 mg, p < 0.0001). One cardiac tamponade was observed in both the vHPSD and HPSD groups while the STSF group exhibited an embolic stoke and two pericardial effusions that did not require drainage. Conclusions: In this study, vHPSD demonstrated a comparable safety profile to the other treatment arms. Procedural duration and energy application time was substantially reduced along with sedation requirement notwithstanding the limitations of observational study design, these preliminary findings are promising with respect to periprocedural outcomes and safety of vHPSD however longitudinal outcomes will be essential to assessing the overall efficacy of this novel technology.
RESUMO
BACKGROUND: A small proportion of lamina I neurons of the spinal cord project upon the hindbrain and are thought to engage descending pathways that modulate the behavioural response to peripheral injury. Early postnatal development of nociception in rats is associated with exaggerated and diffuse cutaneous reflexes with a gradual refinement of responses over the first postnatal weeks related to increased participation of inhibitory networks. This study examined the postnatal development of lamina I projection neurons from postnatal day 3 (P3) until P48. RESULTS: At P3, a subset of lamina I neurons were found to express the neurokinin 1 (NK1) receptor. Using fluorogold retrograde tracing, we found that the NK1 positive neurons projected upon the parabrachial nucleus (PB) within the hindbrain. Using c-fos immunohistochemistry, we showed that lamina I and PB neurons in P3 rats responded to noxious stimulation of the periphery. Finally, ablation of lamina I neurons with substance-P saporin conjugates at P3 resulted in increased mechanical sensitivity from P45 onwards compared to control animals of the same age. CONCLUSIONS: These results suggest that the lamina I pathway is present and functional at least from P3 and required for establishing and fine-tuning mechanical sensitivity in adult rats.