Cognitive outcomes post-catheter ablation for atrial fibrillation: a systematic review and meta-analysis

Funding Acknowledgements

Type of funding sources: None.

Background

Atrial fibrillation (AF) is a known risk factor for cognitive impairment and dementia. Recent data suggests that successful restoration of sinus rhythm by catheter ablation improves cognitive outcomes. Purpose: Our aim was to perform a systematic review and meta-analysis of the available data regarding the effectiveness of AF catheter ablation on neurocognitive outcomes. Methods: A comprehensive literature search was performed through December 1, 2020, for all eligible studies comparing neurocognitive outcomes in AF patients with or without AF catheter ablation. Clinical outcomes included rate of dementia, cognitive function by Montreal Cognitive Assessment (MOCA) and Mini-Mental State Examination (MMSE) scores. Additional outcomes included the impact of time in sinus rhythm on neurocognitive outcomes. Results: We identified 11 studies which evaluated the effect of AF catheter ablation on dementia rate, MMSE and MOCA score. Meta-analysis of observational results indicates a decreased risk of dementia (risk ratio 0.51; 95% CI: 0.43 to 0.60; p <0.001) and an improvement in MOCA scores (2.92 points, p < 0.001) but not MMSE scores in patients undergoing AF catheter ablation compared to medical therapy. In addition, the maintenance of sinus rhythm was identified as a significant factor in dementia rate and improvement of MMSE and MOCA scores observed post catheter ablation therapy. Conclusion: AF catheter ablation may reduce the incidence of dementia and improve cognitive function. A large-scale randomized control trial is warranted before recommendations can be made regarding AF ablation and cognitive outcomes. Abstract Figure.

Mesenchymal stem cell therapy promotes corneal allograft survival in rats by local and systemic immunomodulation

Mesenchymal stem cells (MSCs) are being investigated extensively due to their ability to dampen immune responses. Here, we tested the ability of MSCs from three distinct sources to prolong rat corneal allograft survival. A fully allogeneic rat cornea transplant model (DA to LEW) was used. Recipient rats received 1 × 10(6) MSCs (syn [LEW], allo [DA] or third-party [Wistar Furth]) intravenously 7 days before transplantation and again on the day of transplantation (day 0). A high percentage of untreated and syn-MSC treated allografts were rejected (80% and 100%, respectively). Preactivation of syn-MSCs with interferon gamma also failed to prolong allograft survival. Conversely, corneal allograft survival was significantly prolonged in allo-MSC treated (90%) and third-party MSC treated (80%) allograft recipients. Flow cytometric analysis revealed less infiltrating natural killer T cells in corneas of both allo- and third-party MSC treated animals, coupled with a higher proportion of splenic CD4+Foxp3+ regulatory T cells, compared to controls. In the case of allo- and third-party MSCs, results from a delayed-type hypersensitivity assay clearly showed that hypo-responsiveness was specific for corneal donor-associated allo-antigens. Thus, allo- and third-party MSC treatment prolongs corneal allograft survival by suppressing peripheral immune responses and promoting an intragraft immunoregulatory milieu.

Horizontal strabismus surgical outcomes in a teaching hospital

Strabismus may result in impaired stereopsis, diplopia, undesirable appearance, amblyopia and negative psychological impact. This study provides epidemiological and surgical outcome information about patients attending University College Hospital Galway requiring strabismus surgery. We report a retrospective analysis of 75 consecutive patients, who underwent horizontal strabismus surgery. Sixty-one (81.3%) patients had clinically significant refractive errors, hyperopia being the most common. Thirty-four (45.3%) patients had amblyopia and nine (12%) required further treatment. A cosmetically acceptable result with a post-operative ocular deviation within 25 prism dioptres of straight (grade 2) was achieved in 70/75 (93.3%) of patients. The overall mean change in ocular deviation per mm of muscle operated was 3.25 prism dioptre/mm. The outcomes of strabismus surgery in an Irish hospital compare very favourably with other jurisdictions. This data will help plan service delivery.

The profile of patients attending a triaged eye emergency service

BACKGROUND

Galway University Hospital provides a 24-h referral eye emergency service for patients triaged by a primary health network.

AIMS

A prospective study was designed to evaluate the profile of patients referred to the eye emergency service and an attempt was made to compare the data recorded to those of a walk-in eye casualty.

METHODS

All cases seen in Galway University Hospital eye emergency service over five consecutive weeks in 2012 were recorded and analyzed.

RESULTS

Four hundred and eight cases were seen in total. 312 (76.5 %) were seen during normal working hours and 96 (23.5 %) after-hours. 33.3 % of cases were inflammatory and 31.9 % traumatic. Anterior uveitis [39 cases (9.6 %)] and corneal abrasion [37 cases (9.1 %)] were the most common diagnosis, while bacterial keratitis [9 cases (2.2 %)] and globe rupture/penetration [4 cases (1 %)] were the most serious. 85.6 % of patients were seen within 30 h from referral. A&E department was the main referral source (35 % of cases seen during normal hours and 70.8 % of those seen after-hours). 42.5 % of patients needed to be followed-up in the clinics. Seventy-two patients (17.6 %) were seen after 5 pm, Monday to Monday. Twenty-one were traumatic, 4 required admission and only 9 were deemed inappropriate after assessment.

CONCLUSIONS

Serious eye pathology presents after normal working hours. The triage process results in lower number of minor complaints being referred to the service. Compared to a walk-in casualty, a triaged service manages greater percentage of complex pathology.

Coral larvae conservation: Physiology and reproduction

Coral species throughout the world's oceans are facing severe environmental pressures. We are interested in conserving coral larvae by means of cryopreservation, but little is known about their cellular physiology or cryobiology. These experiments examined cryoprotectant toxicity, dry weight, water and cryoprotectant permeability using cold and radiolabeled glycerol, spontaneous ice nucleation temperatures, chilling sensitivity, and settlement of coral larvae. Our two test species of coral larvae, Pocillopora damicornis (lace coral), and Fungia scutaria (mushroom coral) demonstrated a wide tolerance to cryoprotectants. Computer-aided morphometry determined that F. scutaria larvae were smaller than P. damicornis larvae. The average dry weight for P. damicornis was 24.5%, while that for F. scutaria was 17%, yielding osmotically inactive volumes (V(b)) of 0.22 and 0.15, respectively. The larvae from both species demonstrated radiolabeled glycerol uptake over time, suggesting they were permeable to the glycerol. Parameter fitting of the F. scutaria larvae data yielded a water permeability 2 microm/min/atm and a cryoprotectant permeability = 2.3 x 10(-4) cm/min while modeling indicated that glycerol reached 90% of final concentration in the larvae within 25 min. The spontaneous ice nucleation temperature for F. scutaria larvae in filtered seawater was -37.8+/-1.4 degrees C. However, when F. scutaria larvae were chilled from room temperature to -11 degrees C at various rates, they exhibited 100% mortality. When instantly cooled from room temperature to test temperatures, they showed damage below 10 degrees C. These data suggest that they are sensitive to both the rate of chilling and the absolute temperature, and indicate that vitrification may be the only means to successfully cryopreserve these organisms. Without prior cryopreservation, both species of coral settled under laboratory conditions.

Prosthetic valve endocarditis caused by Veillonella parvula

Veillonella species is a rare cause of endocarditis. We report a case of a 49-year-old man with Veillonella parvula prosthetic valve endocarditis who presented with acute cardiac failure due to valvular dehiscence. His clinical course was complicated by cortical blindness and limb paresis as a result of cerebral embolism. The endocarditis was successfully treated with urgent valve replacement surgery and a prolonged course of metronidazole.

Atrioventricular nodal conduction during atrial fibrillation: role of atrial input modification

BACKGROUND

Posteroseptal ablation of the atrioventricular node (AVN) has been proposed as a means to slow the ventricular rate during atrial fibrillation (AF). The suggested mechanism is elimination of the AVN "slow pathway." On the basis of the unpredictable success of the procedure, we hypothesize that, in fact, the slow pathway is preserved. Therefore, the slowing of the ventricular rate results from reduced bombardment of the AVN.

METHODS AND RESULTS

In 8 rabbit heart atrial-AVN preparations, cooling of the posterior and/or the anterior AVN approaches revealed nonspecific effects on the slow and fast pathway portions of the AVN conduction curve. In 13 other preparations, simulated AF during posterior cooling (n=6) prolonged the His-His (H-H) intervals but did not reveal specific slow pathway injury. In the remaining 7 preparations, AF was applied before and after posteroseptal surgical cuts. During AF with posterior origin, the cuts resulted in longer mean H-H along with slowing of the AVN bombardment rate. However, there was no change in the minimum observed H-H, suggesting an intact slow pathway. During AF with anterior origin, the mean and the shortest H-H remained unchanged before and after the cuts in all preparations. This was associated with the maintenance of high-rate AVN bombardment.

CONCLUSIONS

Posteroseptal ablation does not eliminate the slow pathway. Ventricular rate slowing can be obtained if the ablation procedure results in a posteroanterior intra-atrial block leading to a reduction of the rate of AV nodal bombardment.

Successful use of topical retinoic acid in severe dry eye due to chronic graft-versus-host disease

Topical retinoic acid has proved to be of variable benefit in a number of dry eye disorders of disparate aetiology, in which squamous metaplasia with keratinization of ocular epithelium is present. Its exact role in patients with dry eye however remains in dispute. We describe a case of severe dry eye due to chronic graft-versus-host disease, which was refractory to conventional therapy but which responded remarkably to topical retinoic acid with reversal of conjunctival keratinization and marked resolution of symptoms.

The effects of lisinopril on serum catecholamine concentrations both at rest and on exercise in patients with congestive cardiac failure. A double blind, placebo controlled, parallel group study

Patients with congestive cardiac failure have elevated sympathetic activity at rest which contributes to the pathophysiology of this syndrome. In addition, the sympathetic response to exercise in these patients is abnormal. Sympathetic activity is accurately reflected by serum noradrenaline levels. In a double-blind, placebo-controlled, parallel group study, 16 patients of New York Heart Association (NYHA) functional class II, stabilised on optimum doses of diuretics were randomised into two equal groups, to receive either low-dose Lisinopril, an orally active angiotensin converting enzyme (ACE) inhibitor, or matching placebo, over a 12 week period. At the end of the 12 week treatment phase, there was no significant change in noradrenaline levels at rest (p = 0.33) mid exercise (p = 0.17), or peak exercise (p = 0.69), in the lisinopril group. Both lisinopril and placebo groups improved subjectively as assessed by change in NYHA grade, (p < 0.01 for placebo and p < 0.001 for those given lisinopril). Exercise duration improved significantly in the lisinopril group (p = 0.0296), but not in the placebo group after treatment. Low dose lisinopril is of use in congestive cardiac failure even in the absence of measurable changes in sympathetic tone.

Primary pulmonary hypertension and functional hyposplenism

Primary pulmonary hypertension is a rare disease of unknown case. Functional hyposplenism is characterized by the appearance of abnormal circulating erythrocytes despite the presence of a spleen and is associated with a variety of disease states. A case of primary pulmonary hypertension associated with functional hyposplenism is described in this report.

A critical appraisal of "terminal ventriculostomy" for the treatment of syringomyelia

The clinical course of 31 patients who underwent attempted excision of the filum terminale and tip of the conus for syringomyelia is summarized. Of these patients, 17 had had some previous surgical intervention. Eleven patients were continuing to deteriorate at the time of the operation. In three cases, marked postoperative improvement was reported, and objective improvement was thought to result from the conus excision. Eighteen more patients claimed improvement in their preoperative symptoms of loss of pain sensibility, deafness, or reduced motor function, although most of such claims were unverified by objective clinical assessment. Sixteen of the patients who improved have since proceeded to deteriorate. In five of the patients, there was a long-standing improvement of at least subjective phenomena. Thirteen patients were not improved even subjectively and some of these have continued to grow worse. Proof that the greater part of the syrinx was in communication with the conus or filum was difficult to obtain even when the conus was dilated. No correlations have been found to suggest that the operation might be more effective if the central canal was patent at the conus or the filum, nor was there a correlation between a good clinical result and either the age of the patient or the age of the syrinx as judged by the history. The operation did not seem to be more or less beneficial if previous surgery had been performed. The suggestion is made that for syringomyelia with hindbrain abnormalities, other than dense arachnoiditis (particularly if there is evidence of pressure dissociation at the foramen magnum), craniovertebral decompression remains the procedure of choice. In syringomyelia with marked hydrocephalus, drainage by a valved shunt may be the preferred first procedure. If myelotomy is planned it should probably be done where the syrinx is wide, and it is more likely to succeed if the syrinx is drained to a low-pressure area outside the theca, such as the peritoneum or pleura, rather than the subarachnoid space.