Background: Left atrial appendage (LAA) occlusion is an alternative to anticoagulation for stroke prevention in patients with atrial fibrillation. Accurate device sizing is crucial for optimal outcome. Patient-specific LAA models can be created using three-dimensional (3D) printing from 3D transesophageal echocardiographic (TEE) images, allowing in vitro model testing for device selection. The aims of this study were to assess the association of model-based device selection with procedural safety and efficacy and to determine if preprocedural model testing leads to superior outcomes. Methods: In 72 patients who underwent imaging-guided LAA occlusion, 3D models of the LAA were created from 3D TEE data sets retrospectively (retrospective cohort). The optimal device determined by in vitro model testing was compared with the actual device used. Associations of model-match and model-mismatch device sizing with outcomes were analyzed. In another 32 patients, device selection was prospectively guided by 3D models in adjunct to imaging (prospective cohort). The impact of model-based sizing on outcomes was assessed by comparing the two cohorts. Results: Patients in the retrospective cohort with model-mismatch sizing had longer procedure times, more implantation failures, more devices used per procedure, more procedural complications, more peridevice leak, more device thrombus, and higher cumulative incidence rates of ischemic stroke and cardiovascular or unexplained death (P < .05 for all) over 3.0 6 2.3 years after LAA occlusion. Compared with the retrospective imaging-guided cohort, the prospective model-guided patients achieved higher implantation success and shorter procedural times (P < .05) without complications. Clinical device compression (r = 0.92) and protrusion (r = 0.95) agreed highly with model testing (P < .0001). Predictors for sizing mismatch were nonwindsock morphology (odds ratio, 4.7) and prominent LAA trabeculations (odds ratio, 7.1). Conclusions: In patients undergoing LAA occlusion, device size selection in agreement with 3D-printed modelbased sizing is associated with improved safety and efficacy. Preprocedural device sizing with 3D models in adjunct to imaging guidance may lead to superior outcomes.

The postnatal development of the optic nerve in the golden hamster has been examined using the electron microscope. The number of the optic fibres present in the optic nerve showed an initial increase during the first day after birth but it declined afterwards and tapered off after Day 16. At its peak on postnatal Day 1, there was an average of 314,629 axons in the optic nerve but when the animal reached adulthood only 109,587 fibres remained amounting to about 65% loss of the total fibre population. The period of axon loss coincided with the appearance of large patches of degenerated profiles in the optic nerve. The occurrence of the optic fibre loss has been implied to correlate with the time when the retinal projections were undergoing a dynamic reorganization at the target sites during the process of establishing the adult patterns of retinofugal connections.

Introduction: Hydroxychloroquine has been used for rheumatological diseases for many decades and is considered a safe medication. With the COVID-19 outbreak, there has been an increase in reports associating cardiotoxicity with hydroxychloroquine. It is unclear if cardiotoxic profile of hydroxychloroquine is previously underreported in the literature, or a new manifestation of COVID-19 and therapeutic interventions. This manuscript evaluates the incidence of cardiotoxicity associated with hydroxychloroquine prior to onset of COVID-19. Methods: PubMED, EMBASE, and Cochrane databases were searched for keywords derived from MeSH terms, prior to 4/9/2020. Inclusion eligibility was based on appropriate reporting of cardiac conditions and study design. Results: Sixty-nine articles were identified (58 case reports, 11 case series). Majority (84%) of patients were female, with a median age of 49.2(range 16-92) years. Fifteen of 185 patients with cardiotoxic events were in the setting of acute intentional overdose. In acute overdose, the median ingestion was 17,857  14,873 mg. Two of 15 patients died after acute intoxication. In patients with long-term hydroxychloroquine use (10.5 ± 8.9 years), new onset systolic heart failure occurred in 54 of 155 patients (35%) with median cumulative ingestion of 1,493,800 ± 995,517 mg. The majority of patients improved with withdrawal of hydroxychloroquine and standard therapy. Conclusions: Millions of hydroxychloroquine doses are prescribed annually. Prior to COVID-19 pandemic, cardiac complications attributed to hydroxychloroquine were uncommon. Further studies are needed to understand the impact of COVID-19 on the cardiovascular system to understand presence or absence of potential medication interactions with hydroxychloroquine in this new pathophysiological state.