Sleep-disordered breathing in patients with implanted cardiac devices: validation of the ApneaScanTM algorithm and implications for prognosis

Aims Sleep-disordered breathing (SDB) is common in heart failure (HF) and frequently undiagnosed. The ApneaScanTM algorithm, available on certain ICD and CRT devices, uses changes in transthoracic impedance with breathing to quantify SDB. This research tests 3 hypotheses: 1) The ApneaScanTM algorithm can accurately detect moderate-to-severe SDB in patients with HF 2) There is minimal night-to-night variability in the ApneaScanTM-determined severity of SDB 3) Those with moderate-to-severe SDB, assessed by ApneaScanTM, have a higher rate of adverse cardiovascular events than those without. Methods Patients with EF≤40% and ICD or CRT devices incorporating ApneaScanTM were recruited. For hypothesis 1, 54 subjects underwent a successful sleep polygraphy study and simultaneous download of ApneaScanTM data. 22 subjects (44%) had undiagnosed moderate-to-severe SDB. The area under the ROC curve was 0.84 for the diagnosis of moderate-to-severe SDB. The optimal ApneaScan cut-off was 30.5/hour (sensitivity 95%, specificity 69%, positive predictive value 68%, negative predictive value 95%). For hypothesis 2, ApneaScanTM data over 28- and 92-nights in 35 patients was reviewed. There was minimal variability in SDB and no significant difference between durations. For hypothesis 3, 72 patients were followed up at a median of 532 (IQR 386-736) days.Mean event-free survival was 660±344 days (95% CI 535-785 days) in the insignificant SDB group and 854±413 days (95% CI 730-978 days) in the significant SDB group (p=0.25 by log rank test). Conclusions ApneaScanTM, with an optimal cut-off of 30.5 events/hour, is a sensitive means of screening for SDB in patients with HF with a high negative predictive value. Readings above 30.5/hour require further investigation with a sleep study. Night-to-night variability in SDB is minimal and repeat sleep studies should be reserved for those with ‘borderline’ AHI. In this cohort, the presence of SDB was not associated with adverse cardiovascular outcomes. Recruitment is on-going to test this further.Open Acces

The story of Savitri in the Mahabharata: a lineal interpretation

This paper presents a new interpretation of the story of Savitri as presented in the Mahabharata. Savitri is viewed as an intended putrika, or lineal daughter, for her father, and the death of her husband and the misfortunes of her father-in-law are explained as corollaries of this circumstance; but at the last minute Savitri switches her allegiance to her husband and his line, becoming a pativrata rather than a putrika. Following a prompt in the Mahabharata text, the paper concludes with an exploration, on the Savitri model, of Draupadi’s relationship to the Pandava line. The death of the Draupadeyas and the resuscitation of Parikshit are viewed in terms of a symbolic switch from the putrika to the pativrata mode of operation

New meaning for NLP: the trials and tribulations of natural language processing with GPT-3 in ophthalmology

Natural language processing (NLP) is a subfield of machine intelligence focused on the interaction of human language with computer systems. NLP has recently been discussed in the mainstream media and the literature with the advent of Generative Pre-trained Transformer 3 (GPT-3), a language model capable of producing human-like text. The release of GPT-3 has also sparked renewed interest on the applicability of NLP to contemporary healthcare problems. This article provides an overview of NLP models, with a focus on GPT-3, as well as discussion of applications specific to ophthalmology. We also outline the limitations of GPT-3 and the challenges with its integration into routine ophthalmic care

Successful Identification of and Discrimination Between Atrial and Ventricular Arrhythmia with the Aid of Pacing and Defibrillator Devices

The presence of supraventricular tachycardia is the leading cause of inappropriate shock in ICD recipients, and it can be a significant cause of morbidity, psychological distress and worsened clinical outcome. Modern pacing and ICD systems offer a number of discriminators that are integrated into algorithms to differentiate sustained ventricular tachycardia from supraventricular tachycardia. These algorithms can be adapted and optimised for each individual patient to ensure that only those arrhythmias that need treatment through the use of an ICD, are actually treated. This review summarises the single- and dual-chamber discriminators that can be used in the detection and classification of tachyarrhythmias

Robustness of an Artificial Intelligence Solution for Diagnosis of Normal Chest X-Rays

Purpose: Artificial intelligence (AI) solutions for medical diagnosis require thorough evaluation to demonstrate that performance is maintained for all patient sub-groups and to ensure that proposed improvements in care will be delivered equitably. This study evaluates the robustness of an AI solution for the diagnosis of normal chest X-rays (CXRs) by comparing performance across multiple patient and environmental subgroups, as well as comparing AI errors with those made by human experts. Methods: A total of 4,060 CXRs were sampled to represent a diverse dataset of NHS patients and care settings. Ground-truth labels were assigned by a 3-radiologist panel. AI performance was evaluated against assigned labels and sub-groups analysis was conducted against patient age and sex, as well as CXR view, modality, device manufacturer and hospital site. Results: The AI solution was able to remove 18.5% of the dataset by classification as High Confidence Normal (HCN). This was associated with a negative predictive value (NPV) of 96.0%, compared to 89.1% for diagnosis of normal scans by radiologists. In all AI false negative (FN) cases, a radiologist was found to have also made the same error when compared to final ground-truth labels. Subgroup analysis showed no statistically significant variations in AI performance, whilst reduced normal classification was observed in data from some hospital sites. Conclusion: We show the AI solution could provide meaningful workload savings by diagnosis of 18.5% of scans as HCN with a superior NPV to human readers. The AI solution is shown to perform well across patient subgroups and error cases were shown to be subjective or subtle in nature

Glandular trichomes on the leaves of Rosmarinus officinalis: Morphology, stereology and histochemistry

Stereological and histochernical analyses of the glandular trichomes on leaves of Rosmarinus officinalis were carried out using light and fluorescence microscopy. Non-glandular and two types of glandular trichomes - peltate and capitate - are described. The stereological method was used for estimating the volume density of epidermis, mesophyll, mechanical tissue, central cylinder, intercellular spaces and volume density of different types of glandular trichomes. The results showed that the volume density of adaxial epidermis was higher than abaxial epidermis. The volume density of peltate trichomes was higher than the volume density of capitate ones. The values obtained for number of peltate and capitate trichomes showed that the capitate trichomes type I were more numerous. The histochernical tests showed positive reactions to proteins and polysaccharides for both types of trichomes, while the phenolic substances were found only in peltate trichomes

A restrictive versus liberal transfusion strategy to prevent myocardial injury in patients undergoing surgery for fractured neck of femur:a feasibility randomised controlled trial (RESULT-NOF)

BackgroundThe optimum transfusion strategy in patients with fractured neck of femur is uncertain, particularly if there is coexisting cardiovascular disease. MethodsWe conducted a prospective, single-centre, randomised feasibility trial of two transfusion strategies. We randomly assigned patients undergoing surgery for fractured neck of femur to a restrictive (haemoglobin, 70–90 g L −1) or liberal (haemoglobin, 90–110 g L −1) transfusion strategy throughout their hospitalisation. Feasibility outcomes included: enrolment rate, protocol compliance, difference in haemoglobin, and blood exposure. The primary clinical outcome was myocardial injury using troponin estimations. Secondary outcomes included major adverse cardiac events, postoperative complications, duration of hospitalisation, mortality, and quality of life. ResultsWe enrolled 200 (22%) of 907 eligible patients, and 62 (31%) showed decreased haemoglobin (to 90 g L −1 or less) and were thus exposed to the intervention. The overall protocol compliance was 81% in the liberal group and 64% in the restrictive group. Haemoglobin concentrations were similar preoperatively and at postoperative day 1 but lower in the restrictive group on day 2 (mean difference [MD], 7.0 g L −1; 95% confidence interval [CI], 1.6–12.4). Lowest haemoglobin within 30 days/before discharge was lower in the restrictive group (MD, 5.3 g L −1; 95% CI, 1.7–9.0). Overall, 58% of patients in the restrictive group received no transfusion compared with 4% in the liberal group (difference in proportion, 54.5%; 95% CI, 36.8–72.2). The proportion with the primary clinical outcome was 14/26 (54%, liberal) vs 24/34 (71%, restrictive), and the difference in proportion was –16.7% (95% CI, –41.3 to 7.8; P=0.18). ConclusionA clinical trial of two transfusion strategies in hip fracture with a clinically relevant cardiac outcome is feasible