Implementing immediate sequential bilateral cataract surgery at Buckinghamshire Healthcare NHS Trust.

BACKGROUND/OBJECTIVES: Immediate sequential bilateral cataract surgery (ISBCS) was first introduced into NICE guidelines in 2017. In this approach, patients undergo cataract surgery on both eyes on the same day. Although increasingly popular, only 0.5% of all cataract operations nationally are performed using this approach. We redesigned our service to routinely offer ISBCS and are now one of the leading NHS providers of ISBCS in the UK. We audited our cataract operations in 2022 and report our initial experiences with ISBCS here. SUBJECTS/METHODS: We redesigned our cataract service to routinely offer ISBCS on the NHS. We audited all cataract operations performed in calendar year 2022. RESULTS: We performed 4652 NHS cataract operations including 498 (10.7%) operations on 249 patients using the ISBCS approach. Trainee surgeons performed 32.5% of these cases. There were two intraoperative complications, both during the second eye operation. One was a suspected suprachoroidal haemorrhage and the other was a posterior capsular rupture post lens implantation. Post-operatively there was one case of retinal detachment requiring vitrectomy following uncomplicated ISBCS and five cases of Irvine-Gass syndrome that were managed medically. CONCLUSIONS: From this data, ISBCS does not pose a greater risk to patients in terms of complications. Allowing trainees to operate on ISBCS cases improves the trainee experience. With appropriate pre-operative counselling, patients listed for unilateral surgery can be converted to ISBCS on the day of operation to fully utilise theatre capacity. Patients listed for ISBCS can also be converted to unilateral surgery on the day of operation when surgeons need time to deal with complications safely.

Potential role of antitachycardia pacing alerts for the reduction of emergency presentations following shocks in patients with implantable cardioverter-defibrillators: implications for the implementation of remote monitoring.

AIMS: Despite increased use of remote monitoring (RM) to follow up implantable cardioverter-defibrillator (ICD) recipients, many patients still receive ICD shocks in the community and present to the emergency department. Our aim was to identify the best predictors of impending shock delivery that can be measured with an ICD and to identify the most appropriate activities to alert physicians to during RM follow-up. METHODS AND RESULTS: All patients presenting to our institution for ICD shock, from November 2011 to November 2014, were enrolled in this prospective study. Patient characteristics, investigation results, and details of electrical activities from ICD interrogation were recorded at presentation. Presentations were classified as potentially avoidable if activities from a list of set criteria were apparent more than 48 h before index shock. Univariate and multivariate analyses were then used to identify predictors of potentially avoidable shocks. In total, 109 emergency presentations were recorded in 90 patients (male: 85%; 57 ± 16 years; ischaemic cardiomyopathy: 49%; LVEF: 34 ± 13%; electrical storm: 40%), of which 26 (24%) were potentially avoidable. Antitachycardia pacing (ATP) episodes were the most important predictor of impending shock. Potentially avoidable shocks were preceded by more episodes of ATP than unavoidable shocks (13 [3-67] vs. 3 [0-10]; P < 0.001). Patients followed up with RM systems configured to generate alerts following ATP delivery experienced significantly less ICD shocks (24 vs. 16%, P < 0.01). CONCLUSION: Remote monitoring systems that generate alerts following ATP delivery could reduce emergency presentations for ICD shock by 24%, as ATP is a key predictor of impending shock delivery.

Remote monitoring of patients with implantable cardioverter-defibrillators: can results from large clinical trials be transposed to clinical practice?

BACKGROUND: Remote monitoring (RM) is increasingly used to follow up patients with implantable cardioverter-defibrillators (ICDs). Randomized control trials provide evidence for the benefit of this intervention, but data for RM in daily clinical practice with multiple-brands and unselected patients is lacking. AIMS: To assess the effect of RM on patient management and clinical outcome for recipients of ICDs in daily practice. METHODS: We reviewed ICD recipients followed up at our institution in 2009 with RM or with traditional hospital only (HO) follow-up. We looked at the effect of RM on the number of scheduled ambulatory follow-ups and urgent unscheduled consultations, the time between onset of asymptomatic events to clinical intervention and the clinical effectiveness of all consultations. We also evaluated the proportion of RM notifications representing clinically relevant situations. RESULTS: We included 355 patients retrospectively (RM: n=144, HO: n=211, 76.9% male, 60.3±15.2 years old, 50.1% with ICDs for primary prevention and mean left ventricular ejection fraction 35.5±14.5%). Average follow-up was 13.5 months. The RM group required less scheduled ambulatory follow-up consultations (1.8 vs. 2.1/patient/year; P<0.0001) and a far lower median time between the onset of asymptomatic events and clinical intervention (7 vs. 76 days; P=0.016). Of the 784 scheduled ambulatory follow-up consultations carried out, only 152 (19.4%) resulted in therapeutic intervention or ICD reprogramming. We also found that the vast majority of RM notifications (61.9%) were of no clinical relevance. CONCLUSION: RM allows early management of asymptomatic events and a reduction in scheduled ambulatory follow-up consultations in daily clinical practice, without compromising safety, endorsing RM as the new standard of care for ICD recipients.

Predictors of advanced His-Purkinje conduction disturbances in patients with unexplained syncope and bundle branch block.

BACKGROUND: For patients presenting with syncope and bundle branch block (BBB), results during electrophysiological studies (EPS) might depend on the electrocardiographic pattern of conduction disturbances. We sought to identify predictors of advanced His-Purkinje conduction disturbances (HPCDs) in these patients. METHODS: In this retrospective multicentre study, patients were included who: (1) presented with unexplained syncope; (2) had BBB (QRS duration ≥ 120 ms); and (3) were investigated with EPS. HPCD was diagnosed if the baseline His-ventricular interval was ≥ 70 ms or if second- or third-degree His-Purkinje block was observed during atrial pacing or pharmacological challenge. RESULTS: Of the 171 patients studied (72 ± 13 years, 64% male sex, mean left ventricular ejection fraction 57 ± 9%), advanced HPCD was found in 73 patients (43%). The following electrocardiographic features were associated with HPCD (P = 0.01): isolated right BBB (34.4%), right BBB with left anterior fascicular block (36.4%), left BBB (46.2%), and right BBB with left posterior fascicular block (LPFB, 78.6%). Multivariate analysis identified first-degree atrioventricular block (odds ratio, 2.4; 95% confidence interval, 1.2-4.7; P = 0.01) and LPFB (odds ratio, 4.8; 95% confidence interval, 1.3-18.5; P = 0.02) as the only 2 independent predictors of advanced HPCD. CONCLUSIONS: For patients presenting with syncope and BBB, first-degree atrioventricular block and LPFB increased the likelihood of finding HPCDs during EPS. However, no single electrocardiographic feature could consistently predict the outcome of EPS, so this investigation is still necessary in assessing the need for pacemaker implantation, irrespective of the precise appearance of abnormalities on ECG.

Pregnancy in women with an implantable cardioverter-defibrillator: is it safe?

AIMS: To describe obstetric/neonatal and cardiac outcomes for a cohort of women carrying implantable cardioverter-defibrillators (ICDs) during pregnancy. METHODS AND RESULTS: All women in routine follow-up at our institution for ICD implantation who became pregnant between 2006 and 2013 were included in this study. All ICDs were pre-pectoral devices with bipolar endocardial leads. Obstetric/neonatal and cardiac outcomes were assessed during pregnancy and post-partum. Twenty pregnancies were conceived by 12 women carrying ICD devices, 14 of which resulted in live births and none in maternal death. Seven of these women had structural cardiomyopathies and five had channelopathies. No device-related complications were recorded. Twelve shocks (nine transthoracic and three from ICDs) were experienced during pregnancy by two women, one of whom miscarried shortly afterwards at 4 weeks gestation. One stillbirth, three miscarriages and one termination were recorded for women with long QT syndrome, repaired tetralogy of Fallot and repaired Laubry-Pezzi syndrome, respectively. Intrauterine growth restriction, low birth weight, and neonatal hypoglycaemia were recorded in four, three, and five pregnancies, respectively. CONCLUSIONS: Pregnancy had no effect on ICD operation and no evidence was found to link ICD carriage with adverse pregnancy outcomes, although one miscarriage may have been induced by ICD shock therapy. A worsening of cardiac condition occurs in specific cardiac diseases and ß-blocker therapy should be continued for all women carrying ICDs in pregnancy as the benefits outweigh the risks of taking this medication.

Clinical implications of left ventricular assist device implantation in patients with an implantable cardioverter-defibrillator.

PURPOSE: This study aims to study the clinical implications of the concomitant use of a left ventricular assist device (LVAD) and an implantable cardioverter-defibrillator (ICD). METHODS: In this retrospective study, all patients who underwent LVAD (Heart Mate II) implantation with concomitant ICD therapy at our institution between June 2007 and August 2012 were included. We sought to investigate (1) the electromagnetic interference between LVAD and ICD telemetry, (2) the effect of LVAD implantation on right ventricular (RV) lead parameters and (3) the ventricular tachyarrhythmias (VAs) that occur post-LVAD implantation. RESULTS: Of the 23 patients (53 ± 9 years, 73 % male, LVEF 19 ± 9 %) included, ICD telemetry was lost in four patients post-LVAD implantation (Saint-Jude-Medical Atlas V-193, V-240, V-243, and Sorin CRT-8750), prompting either use of a metal shield (n = 1), a change in position of the programmer head (n = 1) or ICD replacement (n = 2). LVAD implantation was associated with a decrease in both RV signal amplitude (p = 0.04) and RV impedance (p < 0.01), and a trend towards an increased RV pacing threshold (p = 0.08), without affecting clinical outcome. Eleven patients (47.8 %) experienced VAs after LVAD implantation, which on the whole were well tolerated. Their occurrence was strongly linked to a history of VAs before device implantation (p < 0.01). CONCLUSIONS: Electromagnetic interference between LVADs and ICD telemetry may necessitate ICD replacement. LVAD placement is associated with significant changes in RV lead parameters that have minimal clinical significance. VAs occur in approximately half of LVAD patients seen and their occurrence is strongly related to a history of VAs prior to LVAD implantation.

Fast measurement of sarcomere length and cell orientation in Langendorff-perfused hearts using remote focusing microscopy.

RATIONALE: Sarcomere length (SL) is a key indicator of cardiac mechanical function, but current imaging technologies are limited in their ability to unambiguously measure and characterize SL at the cell level in intact, living tissue. OBJECTIVE: We developed a method for measuring SL and regional cell orientation using remote focusing microscopy, an emerging imaging modality that can capture light from arbitrary oblique planes within a sample. METHODS AND RESULTS: We present a protocol that unambiguously and quickly determines cell orientation from user-selected areas in a field of view by imaging 2 oblique planes that share a common major axis with the cell. We demonstrate the effectiveness of the technique in establishing single-cell SL in Langendorff-perfused hearts loaded with the membrane dye di-4-ANEPPS. CONCLUSIONS: Remote focusing microscopy can measure cell orientation in complex 2-photon data sets without capturing full z stacks. The technique allows rapid assessment of SL in healthy and diseased heart experimental preparations.

Aberration-free three-dimensional multiphoton imaging of neuronal activity at kHz rates.

Multiphoton microscopy is a powerful tool in neuroscience, promising to deliver important data on the spatiotemporal activity within individual neurons as well as in networks of neurons. A major limitation of current technologies is the relatively slow scan rates along the z direction compared to the kHz rates obtainable in the x and y directions. Here, we describe a custom-built microscope system based on an architecture that allows kHz scan rates over hundreds of microns in all three dimensions without introducing aberration. We further demonstrate how this high-speed 3D multiphoton imaging system can be used to study neuronal activity at millisecond resolution at the subcellular as well as the population level.

Agitation-free multiphoton microscopy of oblique planes.

The scanning two-photon fluorescence microscope produces optically sectioned images from the focal plane. It is sometimes desirable to acquire images from other planes of the specimen that are inclined with respect to the focal plane. In this Letter, we discuss the issues concerned with acquiring such images together with the effects of the inclination angle on image resolution and sectioning strength. To obtain images from oblique planes at high speed, a two-photon system was built wherein a novel optical system is used to provide aberration-free scanning.

Image-based adaptive optics for two-photon microscopy.

We demonstrate wavefront sensorless aberration correction in a two-photon excited fluorescence microscope. Using analysis of the image-formation process, we have developed an optimized correction scheme permitting image-quality improvement with minimal additional exposure of the sample. We show that, as a result, our correction process induces little photobleaching and significantly improves the quality of images of biological samples. In particular, increased visibility of small structures is demonstrated. Finally, we illustrate the use of this technique on various fresh and fixed biological tissues.

Real-time slit scanning microscopy in the meridional plane.

The standard microscope architecture around which confocal microscopes are built imposes fundamental restrictions on the speed with which images (three-dimensional data sets) can be obtained. Commercially available slit scanning confocal microscopes are able to produce optically sectioned images at frame rates well in excess of 100 Hz. However only the focal (x-y) plane can be imaged at this speed. To image a volume specimen it is necessary to physically change the distance between the objective lens and the specimen. This refocusing process is often necessarily slow and represents a bottleneck to the speed of image acquisition. We describe the construction of a slit scanning confocal microscope based on what we know to be a novel microscope architecture, which permits images of other planes and, particular, the meridional (x-z) plane to be acquired in real time.

Real-time extended depth of field microscopy.

We describe an optical microscope system whose focal setting can be changed quickly without moving the objective lens or specimen. Using this system, diffraction limited images can be acquired from a wide range of focal settings without introducing optical aberrations that degrade image quality. We combine this system with a real time Nipkow disc based confocal microscope so as to permit the acquisition of extended depth of field images directly in a single frame of the CCD camera. We also demonstrate a simple modification that enables extended depth of field images to be acquired from different angles of perspective, where the angle can be changed over a continuous range by the user in real-time.

Adaptive optics for structured illumination microscopy.

We implement wave front sensor-less adaptive optics in a structured illumination microscope. We investigate how the image formation process in this type of microscope is affected by aberrations. It is found that aberrations can be classified into two groups, those that affect imaging of the illumination pattern and those that have no influence on this pattern. We derive a set of aberration modes ideally suited to this application and use these modes as the basis for an efficient aberration correction scheme. Each mode is corrected independently through the sequential optimisation of an image quality metric. Aberration corrected imaging is demonstrated using fixed fluorescent specimens. Images are further improved using differential aberration imaging for reduction of background fluorescence.

Aberration-free optical refocusing in high numerical aperture microscopy.

We describe a method of optical refocusing for high numerical aperture (NA) systems that is particularly relevant for confocal and multiphoton microscopy. This method avoids the spherical aberration that is common to other optical refocusing systems. We show that aberration-free images can be obtained over an axial scan range of 70 mum for a 1.4 NA objective lens. As refocusing is implemented remotely from the specimen, this method will enable high axial scan speeds without mechanical interference between the objective lens and the specimen.