Elective direct current cardioversion of atrial fibrillation - silent brain infarction and health related quality of life.

INTRODUCTION: Atrial fibrillation (AF) increases the risk for stroke, dementia and impaired health related quality of life (HRQL). Elective direct current cardioversion (ECV) is often used to restore sinus rhythm, but is associated with thromboembolism. While larger strokes usually produce symptoms, subclinical ones may go unrecognized and may cause cognitive and functional decline over time. In the current study, we sought to evaluate the effects of ECV on silent brain infarctions and HRQL in patients with AF. METHODS: Patients with AF (n=46) underwent brain magnetic resonance imaging (MRI) and HRQL assessment using the EuroQL-5D5L questionnaire before and after ECV. Implantable loop recorders (ILR) were used to observe the rate of early AF recurrences within the first thirty days. All patients were treated with anticoagulants according to guidelines. The primary endpoint was silent brain infarction assessed by brain MRI within the first two weeks after ECV. Secondary endpoints were the change in HRQL and its association with AF recurrence at follow-up and by ILR recordings. RESULTS: New silent brain infarction after ECV was detected in one patient. At follow-up visit after 19.1 days AF recurrence was detected by 12-lead ECG in 13 patients (28.3 %), whereas 27 patients (58.7 %) had AF recurrence recorded by ILR within the first thirty days after ECV. European Heart Rhythm Association (EHRA) symptom score and the EuroQL-5d5L score were improved after ECV. CONCLUSION: Silent brain infarctions may occur after ECV despite anticoagulation treatment. Early AF recurrence is frequent. ECV positively affects HRQL mainly in those patients with sustained sinus rhythm at follow-up.

In vivo distribution of cerebrospinal fluid tracer in human upper spinal cord and brain stem.

BACKGROUNDIntrathecal injection is an attractive route through which drugs can be administered and directed to the spinal cord, restricted by the blood-spinal cord barrier. However, in vivo data on the distribution of cerebrospinal fluid (CSF) substances in the human spinal cord are lacking. We conducted this study to assess the enrichment of a CSF tracer in the upper cervical spinal cord and the brain stem.METHODSAfter lumbar intrathecal injection of a magnetic resonance imaging (MRI) contrast agent, gadobutrol, repeated blood samples and MRI of the upper cervical spinal cord, brain stem, and adjacent subarachnoid spaces (SAS) were obtained through 48 hours. The MRI scans were then analyzed for tracer distribution in the different regions and correlated to age, disease, and amounts of tracer in the blood to determine CSF-to-blood clearance.RESULTSThe study included 26 reference individuals and 35 patients with the dementia subtype idiopathic normal pressure hydrocephalus (iNPH). The tracer enriched all analyzed regions. Moreover, tracer enrichment in parenchyma was associated with tracer enrichment in the adjacent SAS and with CSF-to-blood clearance. Clearance from the CSF was delayed in patients with iNPH compared with younger reference patients.CONCLUSIONA CSF tracer substance administered to the lumbar thecal sac can access the parenchyma of the upper cervical spinal cord and brain stem. Since CSF-to-blood clearance is highly individual and is associated with tracer level in CSF, clearance assessment may be used to tailor intrathecal treatment regimes.FUNDINGSouth-Eastern Norway Regional Health and Østfold Hospital Trust supported the research and publication of this work.

Human parasagittal dura is a potential neuroimmune interface.

Parasagittal dura (PSD) is located on both sides of the superior sagittal sinus and harbours arachnoid granulations and lymphatic vessels. Efflux of cerebrospinal fluid (CSF) to human PSD has recently been shown in vivo. Here we obtain PSD volumes from magnetic resonance images in 76 patients under evaluation for CSF disorders and correlate them to age, sex, intracranial volumes, disease category, sleep quality, and intracranial pressure. In two subgroups, we also analyze tracer dynamics and time to peak tracer level in PSD and blood. PSD volume is not explained by any single assessed variable, but tracer level in PSD is strongly associated with tracer in CSF and brain. Furthermore, peak tracer in PSD occurs far later than peak tracer in blood, implying that PSD is no major efflux route for CSF. These observations may indicate that PSD is more relevant as a neuroimmune interface than as a CSF efflux route.

In vivo assessment of cerebrospinal fluid efflux to nasal mucosa in humans.

Extra-vascular molecular clearance routes from the brain and cerebrospinal fluid (CSF) remain insufficiently characterized in humans. Animal studies consistently suggest that the cribriform plate and nasal lymphatic vessels are crucial for molecular clearance from CSF. In this study, we aimed to examine human in vivo transport of a CSF tracer from CSF to nasal mucosa. We hypothesised a CSF tracer would enrich in nasal mucosa provided that nasal lymphatic drainage has a significant role in CSF molecular clearance. Consecutive magnetic resonance imaging during 48 h after intrathecal administration of a tracer (gadobutrol) was performed in 24 patients. Despite a strong enrichment of CSF tracer in CSF spaces nearby the cribriform plate, there was no significant enrichment of CSF tracer in nasal mucosa, as measured in superior, medial and inferior turbinates, or in the nasal septum. Therefore, this in vivo study questions the importance of CSF drainage to the human nasal mucosa and emphasizes the need of further human studies.