[Feasibility of radiofrequency ablation for cancer patients with atrial fibrillation].

Objective: To analyze the impact of cancer on the recurrence rate of atrial fibrillation (AF) after AF radiofrequency ablation and further evaluate the feasibility of radiofrequency ablation therapy in cancer patients with AF. Methods: This study was a single-center, retrospective study. Cancer patients with AF undergoing radiofrequency ablation for the first time in the First Affiliated Hospital of Dalian Medical University from May 30, 2008 to September 30, 2018 were included (cancer group). AF patients without cancer undergoing radiofrequency ablation for the first time during the same period served as non-cancer group. Clinical data including age, gender, past history, cancer and AF-related parameters, etc. were analyzed. Patients were followed up after radiofrequency ablation. The primary endpoints were AF recurrence or all-cause death. Kaplan-Meier survival analysis was used to analyze the effect of cancers on the recurrence after AF ablation. The multivariate cox regression analysis was further applied to correct for other confounding factors to analyze whether the impact of cancers on the recurrence of atrial fibrillation was statistically significant. Results: A total of 90 patients were enrolled, there were 30 patients in the cancer group (mean age (64.8±6.6) years, 16 (53.3%) males) and 60 patients in the non-cancer group (mean age (63.6±6.2) years, 32 (53.3%) males). Clinical data, such as age, gender, and cancer treatment, were similar between the two groups. During an average follow-up period of (328.7±110.2) days, there were 6 AF recurrences (recurrence rate 20.0%) in the cancer group, and 17 AF recurrences (recurrence rate 28.3%) in the control group. AF recurrence rate was similar between the two groups (P>0.05). During the follow-up period, there was no all-cause death in the two groups. Kaplan-Meier survival analysis showed that cancer was not related to AF recurrence after radiofrequency ablation (P = 0.383). After adjusting for other confounding factors, the multivariate Cox regression analysis showed that cancer was not an independent predictor of AF recurrence after radiofrequency ablation (HR=0.508, 95%CI: 0.192-1.342, P = 0.172). Conclusions: The combination of cancer has no impact on the recurrence of AF after radiofrequency ablation. For cancer patients with AF, radiofrequency ablation therapy can be considered as a feasible heart rhythm control treatment strategy.

Single shot, time-resolved measurement of the coherence properties of OCT swept source lasers.

A novel, time-resolved interferometric technique is presented that allows the reconstruction of the complex electric field output of a swept source laser in a single-shot measurement. The power of the technique is demonstrated by examining a short cavity swept source designed for optical coherence tomography (OCT) applications with a spectral width of over 100 nm. The novel analysis allows a time-resolved real-time characterization of the roll-off, optical spectrum, linewidth, and coherence properties of a dynamic, rapidly swept laser source.

Dynamics of a short cavity swept source OCT laser.

We investigate the behaviour of a short cavity swept source laser with an intra cavity swept filter both experimentally and theoretically. We characterise the behaviour of the device with real-time intensity measurements using a fast digital oscilloscope, showing several distinct regimes, most notably regions of mode-hopping, frequency sliding mode-locking and chaos. A delay differential equation model is proposed that shows close agreement with the experimental results. The model is also used to determine important quantities such as the minimum and maximum sweep speeds for the mode-locking regime. It is also shown that by varying the filter width the maximum sweep speed can be increased but at a cost of increasing the instantaneous linewidth. The consequent impacts on optical coherence tomography applications are analysed.

Direct observation of magnetic contrast obtained by photoemission electron microscopy with deep ultra-violet laser excitation.

Magnetic circular dichroism (MCD) and magnetic linear dichroism (MLD) have been investigated in a photoemission electron microscopy (PEEM) system excited by a deep ultra-violet (DUV) laser (with λ = 177.3 nm and hυ = 7.0 eV) for the first time. High resolution PEEM magnetic images (down to 43.2 nm) were directly obtained on a (001)-oriented magnetic FePt film surface with a circularly-polarized light under normal incidence. Furthermore, a stepped Cr seeding layer was applied to induce the formation of large-area epitaxial FePt films with (001) and (111) two orientations, where MLD with large asymmetry was observed in the transition area of two phases. It demonstrates that DUV laser can be a powerful source for high resolution magnetic imaging in the laboratory in absence of synchrotron facilities.