Electrophysiologic mechanism and ablation strategy for macroreentrant biatrial tachycardias after Cox-maze procedures.

BACKGROUND: Different types of recurrent atrial tachycardia (AT) after Cox-maze procedures have been reported, whereas biatrial tachycardia (BiAT) has not been systematically analyzed. OBJECTIVE: In this study, we retrospectively investigated the electrophysiologic characteristics of BiAT after Cox-maze procedures by use of an ultrahigh-density mapping system. METHODS: Of a consecutive 76 patients who underwent catheter ablation of AT after Cox-maze procedures, 12 BiATs were identified. High-density activation mapping was performed in both the left atrium and right atrium in combination with entrainment pacing to confirm the circuit. RESULTS: We classified these BiATs into 2 groups. In group 1 (7 patients), the bidirectional block of maze linear lesions to prevent the macroreentrant AT was achieved; the posterior interatrial connections were involved in the circuit. In group 2 (5 patients), the bidirectional block of maze linear lesions was not blocked, and the most common gap was located at the end of the linear lesion near the annulus. In group 1, all the ATs were terminated by targeting the corresponding left atrium end of the posterior interatrial connections. In group 2, the ATs were terminated by targeting the gap near the annulus. CONCLUSION: The optimal ablation strategy for BiATs after the maze procedure should be based on detailed demonstration of the circuit by high-density mapping.

Liquid Nitrogen Cryoballoon Ablation System for Paroxysmal Atrial Fibrillation: A Multicenter, Prospective, Single-Arm Clinical Trial.

Background: Cryoballoon ablation (CBA) has emerged as an effective treatment for atrial fibrillation (AF). Objectives: This study sought to assess the performance of a novel liquid nitrogen-driven CBA system and evaluate its safety and efficacy in the treatment of drug-resistant paroxysmal atrial fibrillation (PAF). Methods: This was a prospective multicenter single-arm clinical trial with 10 participating tertiary hospitals enrolling 176 patients with PAF. All participants received liquid nitrogen-driven CBA developed by the Cryofocus Medtech Company. Scheduled follow-up was performed before discharge and 3 months, 6 months, and 12 months after CBA. The primary endpoints were defined as 1) treatment success (freedom from antiarrhythmic drugs and atrial tachycardia at 12 months after CBA); and 2) immediate success rate of pulmonary vein isolation. The safety endpoint was the incidence of device- and procedure-related adverse events (AEs) and all-cause mortality. Results: A total of 172 participants were included, with an average age of 59.22 ± 9.25 years and 99 (57.56%) of them men. Immediate success rate was 97.67% (95% CI: 94.15%-99.36%) and 12-month treatment success rate was 82.56% (95% CI: 76.89%-88.23%), including a late recurrence rate of 13.61%. Incidences of device- and procedure-related AEs were 2.27% and 25.00%, respectively. Phrenic nerve palsy (PNP) occurred in 6 patients, of which 5 recovered during follow-up. Although the incidence of total severe AEs was 17.05%, including an all-cause mortality of 0.57%, only 1 case of permanent PNP was related to the CBA procedure. Conclusions: This premarketing prospective multicenter single-arm clinical trial demonstrated that the liquid nitrogen cryoablation system is safe and effective in the treatment of PAF.

Efficacy and safety of the vein of Marshall ethanol infusion with radiofrequency catheter ablation for the treatment of persistent atrial fibrillation in elderly patients.

Background: Increasing age is a significant risk factor for atrial fibrillation (AF) recurrence after catheter ablation (CA). We accomplished this study to evaluate the efficacy and safety of the vein of Marshall (VOM) ethanol infusion (VOM-EI) with CA in elderly patients with persistent AF (PsAF). Methods: This retrospective observational study included 360 consecutive adult patients with PsAF, of which 141 were in the Elder group (age ≥65 years) and 219 were in the Younger group (age <65 years), who underwent the VOM-EI and radiofrequency CA (RFCA) between May 2020 and April 2022. The efficacy endpoint was no recurrence of AF within one year after CA. Results: The VOM-EI was successfully performed in 90.8% of patients from the Elder and 88.6% from the Younger group. All patients achieved PVI; 97.9% of patients from the Elder and 98.6% from the Younger group reached LA roof block, and 93.6% of patients from the Elder and 95.9% from the Younger group achieved MI block. There was no significant difference in 1-year survival without recurrence of AF between the two groups (83.0% and 84.5%, respectively). The incidence of complications within 30 days after the procedure from the two groups was low and did not differ significantly. Conclusion: The VOM-EI combined with RFCA proved to be an effective and safe strategy for treating PsAF in elderly and younger patients.

Aiming to personalized laser therapy for nevus of Ota: melanin distribution dependent parameter optimization.

Aiming to the personalized laser therapy of nevus of Ota (NO), a local thermal non-equilibrium model was employed to optimize laser wavelength, pulse duration, and energy density under different melanin depth and volume fraction. According to our simulation, the optimal pulse duration is between 15 and 150 ns to limit heat transfer inside the hyperplastic melanin, and 50 ns is recommended to decrease the energy absorption by normal melanin in epidermis. Correlations of the minimum and the maximum energy densities are proposed with respect to melanin depth and volume fraction for the 755-nm and 1064-nm lasers. For the same NO type, the therapy window of the 755-nm laser is larger than that of 1064-nm. For NO with shallow depth or low volume fraction, the 755-nm laser is recommended to make the treatment more stable owing to its lager therapy window. For deeper depth or higher volume fraction, the 1064-nm laser is recommended to avoid thermal damage of epidermis. Through comparison with clinical data, the optimized laser parameters are proved practicable since high cure rate can be achieved when energy density falls into the range of predicted therapy window. With developing of non-invasive measurement technology of melanin content and distribution, personalized treatment of NO maybe possible in the near future.

Histopathological evaluation of the R134a multipulsed spray cooling assisted 1210 nm laser lipolysis by the murine model in vivo.

BACKGROUND AND OBJECTIVE: Owing to the greater absorption affinity for lipo-rich tissue than water, the 1210 nm laser is a promising candidate for transcutaneous lipolysis in the near-infrared band. However, fat reduction is limited because laser therapy may yield thermal injury of normal tissue. A new protocol to incorporate multipulsed cryogen spray cooling is beneficial to improve the lipolysis effect, and the parameters of laser and cooling can be optimized via skin histopathological analysis. MATERIALS AND METHODS: A murine in vivo model of inguinal tissue of SD rats was established to test the effectivity of transcutaneous lipolysis protocol by R134a multipulsed spray cooling assisted 1210 nm laser irradiation. Tissue response of lipolysis with/without cooling 10 days post the treatment was evaluated by histopathological analysis of skin samples stained with hematoxylin-eosin (HE), through which safe and effective parameters for lipolysis were determined. RESULTS: From histopathological analysis of the inguinal tissue of SD rats irradiated by the 1210 nm laser alone, the optimal durations are respectively 7 and 3 s (seconds) for low-dosage (6 W) and high-dosage (9 W) therapy, with pronounced lipolysis effect and minimum injury of skin tissue. The multipulsed spray cooling by R134a with a pulse duration of 10 ms (milliseconds), a pulse delay of 2000 ms, and a pulse number of 5 can be introduced to assist the 1210 nm laser therapy with a power of 9 W and a duration of 7 s to achieve desirable fat liquefaction while keeping the complete structure of skin tissue as well as esthetic-related beneficial effects of hair removal and skin rejuvenation. CONCLUSION: Excellent lipolysis effect can be achieved via R134a multipulsed spray cooling assisted high-dosage 1210 nm laser irradiation with reasonably matched laser and cooling parameters. The protocol is as follows: Start MP-CSC for one cycle, and then fire the laser with specific power and duration, while keeping MP-CSC accordingly. This new protocol may promote the safe and effective clinical implement of transcutaneous laser lipolysis in body contouring.