Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Factors involved in correct analysis of intracardiac electrograms captured by Medtronic Inc. pacemakers during tachycardias

Background: To thoroughly investigate the diagnostic information obtained by pacemakers, it is important that the stored intracardiac electrograms (EGMs) are analyzed. However, in Medtronic pacemakers, only a single intracardiac recording channel is available and thus EGM channel selection is critical. Methods: The study population comprised 150 patients who underwent implantation of Medtronic's dual chamber pacemakers with a single intracardiac EGM memory channel. We first set the electrogram channel to “summed,” and the automatic EGM diagnosis during the tachycardia was compared with the manual analysis findings. When the results were not identical for the 2 methods, the atrial EGM (AEGM) and ventricular EGM channels were sequentially selected and the results of each EGM selection were compared to conclude which channel was more valuable for diagnosis of high-rate episodes. The post-ventricular atrial blanking (PVAB) period was adjusted to the shortest interval with a relevant margin to avoid any far-field R wave over-sensing. Results: A total of 130 patients were eventually enrolled. High-rate episodes were observed in 115/130 patients (88%). The results of the automated tachycardia diagnosis obtained using the “summed” EGM differed from those obtained manually in 43/115 patients (37%). Changing the intracardiac EGM channel from “summed” to “AEGM” enabled a much better manual diagnosis with intracardiac EGMs because of improved atrial potential sensing, clearer manifestation of atrial electrograms within the PVAB, and more prominent atrial electrograms fused with the ventricular potentials. The ventricular EGM channel was not as useful as the AEGM channel for tachycardia diagnosis. Conclusions: In Medtronic pacemakers with single intracardiac EGM channel recording capability, AEGM is the most useful of the 3 EGM channel settings; PVAB should also be set to a much shorter value to achieve a more accurate automatic diagnosis

Prevalence of amyloid deposition and cardiac amyloidosis in shoulder disease compared to carpal tunnel syndrome

Background: Cardiac amyloidosis is a fatal disease of severe heart failure caused by the accumulation of amyloid in the myocardium. This disease is often advanced by the time cardiac symptoms appear; therefore, early detection and treatment are critical for a good prognosis. Recently, it has been suggested that cardiac amyloidosis is implicated in several orthopedic diseases, including carpal tunnel syndrome (CTS), which is often reported to precede cardiac dysfunction. Shoulder disease has also been suggested to be associated with cardiac amyloidosis; however, there have been no reports investigating the rate of amyloid deposition in shoulder specimens and the simultaneous prevalence of cardiac amyloidosis. Herein, we investigated the prevalence of intraoperative specimen amyloid deposition and cardiac amyloidosis in shoulder disease and CTS to determine the usefulness of shoulder specimen screening as a predictor of cardiac amyloidosis development. Methods: A total of 41 patients undergoing arthroscopic shoulder surgery and 33 patients undergoing CTS surgery were enrolled in this study. The shoulder group included rotator cuff tears, contracture of the shoulder, synovitis, and calcific tendonitis. In the shoulder group, a small sample of synovium and the long head of the biceps brachii tendon were harvested, while the transverse carpal ligament was harvested from the CTS group. The intraoperative specimens were pathologically examined for amyloid deposition, and patients with amyloid deposition were examined for the presence of cardiac amyloidosis by cardiac evaluation. Results: In the shoulder group, three cases (7.3%) of transthyretin amyloid deposition were found, all of which involved rotator cuff tears. None of these three cases with amyloid deposition were associated with cardiac amyloidosis. When examining the specimens, the amyloid deposition rate in the long head of the biceps brachii tendon was higher than that in the synovium. In the CTS group, 12 cases (36.4%) of transthyretin amyloid deposition were observed. Of these cases, seven underwent cardiac evaluation and two were identified with cardiac amyloidosis. Conclusion: While the prevalence of amyloid deposition and cardiac amyloidosis in the CTS group was consistent with previous reports, the shoulder group showed a lower deposition rate and no concomitant cardiac amyloidosis. Therefore, it remains debatable whether investigating amyloid deposition in samples obtained from shoulder surgery is beneficial for the early detection of cardiac amyloidosis