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Background Ebstein’s anomaly is a rare condition due to incomplete delamination of the tricuspid valve (TV) leaflets with downward displacement of the proximal leaflet attachments. It is associated with a smaller functional right ventricle (RV) and tricuspid regurgitation (TR) that is typically treated with TV replacement or repair. However, future re-intervention poses challenges. We describe a multidisciplinary team approach to re-intervention in a pacing-dependant Ebstein patient with severe bioprosthetic TV regurgitation. Case summary A 49-year-old female patient underwent bioprosthetic TV replacement for severe TR in Ebstein’s. Post-operatively, she developed complete atrioventricular (AV) block necessitating the implantation of a permanent pacemaker which included a coronary sinus (CS) lead as the ventricular lead. Five years later, she presented with syncope due to a failing ventricular pacing lead, and a new RV lead was positioned across the TV bioprosthesis due to the lack of CS options. Two years later, she presented with breathlessness and lethargy with severe TR identified on transthoracic echocardiography. She successfully underwent a percutaneous leadless pacemaker implant, extraction of existing pacing system, and implantation of valve-in-valve TV. Discussion Patients with Ebstein’s anomaly typically undergo TV repair or replacement. Following surgical intervention, owing to the anatomical location, patients can develop AV block requiring a pacemaker. Pacemaker implantation may involve a CS lead to avoid placing a lead across the new TV in efforts to avoid lead induced TR. Over time, these patients not uncommonly require re-intervention that can be challenging especially in pacing-dependant patients with leads across the TV.

The highly organized transverse tubule (t-tubule) network facilitates cardiac excitation–contraction coupling and synchronous cardiac myocyte contraction. In cardiac failure secondary to myocardial infarction (MI), changes in the structure and organization of t-tubules result in impaired cardiac contractility. However, there is still little knowledge on the regional variation of t-tubule remodelling in cardiac failure post-MI. Here, we investigate post-MI t-tubule remodelling in infarct border and remote regions, using serial block face scanning electron microscopy (SBF-SEM) applied to a translationally relevant sheep ischaemia reperfusion MI model and matched controls. We performed minimally invasive coronary angioplasty of the left anterior descending artery, followed by reperfusion after 90 min to establish the MI model. Left ventricular tissues obtained from control and MI hearts eight weeks post-MI were imaged using SBF-SEM. Image analysis generated three-dimensional reconstructions of the t-tubular network in control, MI border and remote regions. Quantitative analysis revealed that the MI border region was characterized by t-tubule depletion and fragmentation, dilation of surviving t-tubules and t-tubule elongation. This study highlights region-dependent remodelling of the tubular network post-MI and may provide novel localized therapeutic targets aimed at preservation or restoration of the t-tubules to manage cardiac contractility post-MI. This article is part of the theme issue ‘The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease’.

The highly organised transverse tubule (t-tubule) network consisting of invaginations of the cell sarcolemma facilitates synchronous cardiac myocyte contraction. This study aimed to investigate post-myocardial infarction (MI) t-tubule remodelling in infarct border and remote regions in a translationally relevant ischaemia reperfusion injury MI model. Six adult sheep were used in this study (n=3 MI, n=3 control). Eight weeks after MI, left ventricular tissue was collected from the remote and border MI regions and from control sheep, processed and imaged using 3D scanning electron microscopy. The t-tubule network was manually segmented using 3dmod. One-way ANOVA with Tukey’s post-hoc correction, unpaired t-tests or Mann-Whitney U test were used where appropriate. Marked disorganisation of the t-tubule network was observed in the border region following MI. Quantitative analysis revealed that in comparison to the control sheep myocardium, the MI border zone had a decreased t-tubule count (0.07 ± 0.007 tubules per μm3 in control vs 0.05 ± 0.004 tubules per μm3 in border; p = 0.02) and showed t-tubule dilation (405 ± 22 nm in control vs 533 ± 30 nm in border; p = 0.02). Whilst there was minimal disorganisation and loss of t-tubules in the MI remote region, we observed increased t-tubule length as a fraction of the cell diameter (0.41 ± 0.04 in control vs 0.56 ± 0.04 in remote; p = 0.045). In addition to gross t-tubule remodelling, we also noted post-MI fragmentation of t-tubules, particularly in the border region. In comparison to control, the number of t-tubule fragments per μm3 was increased in the post MI heart (control, 0.17 ± 0.1 fragments per μm3; border, 2.21 ± 0.7 fragments per μm3; remote, 1.20 ± 0.4 fragments per μm3; p = 0.04 border vs control; p = 0.02 remote vs control). The volume occupied by fragments as a percentage of the cell volume was also higher following MI (control, 0.003 ± 0.002 %; border, 0.071 ± 0.023 %; remote 0.014 ± 0.005 %; p = 0.003 border vs control; p = 0.013 border vs remote). Whilst there was no difference in fragments density between the remote and border regions, there was an increase in the volume of cell occupied by fragments in the MI border region compared to remote. This is explained by a larger average fragment volume in the border region (0.04 ± 0.006 μm3 in border vs 0.01 ± 0.002 μm3 in remote; p Our research shows remodelling of the t-tubule network in the post-MI sheep myocardium. We noted reduced t-tubule count, t-tubule fragmentation, and dilation of remaining t-tubules. Importantly our work shows that these changes occur in a regional manner, being most pronounced in the border region. These changes may reflect regional wall stresses post-MI, and we speculate that our observations may result in region-specific changes to systolic calcium and contractility post-MI. Conflict of Interest Authors declare that there is no conflict of interest.

ObjectiveAtrial fibrillation (AF) ablation services were significantly affected by the COVID-19 pandemic. We aimed to evaluate a symptom-based clinician prioritisation scheme for waiting list management compared with patient-completed quality of life (QoL) scores. We also sought to understand factors influencing QoL, particularly the impact of COVID-19, on patients awaiting AF ablation, via a bespoke questionnaire.MethodsPatients awaiting AF ablation were sent two QoL questionnaires (Atrial Fibrillation Effect on QualiTy of Life (AFEQT) and EuroQol 5D (EQ5D-5L)) and the bespoke questionnaire. At a separate time point, patients were categorised as C1—urgent, C2—priority or C3—routine by their cardiologist based on review of clinic letters.ResultsThere were 118 patients included with priority categorisation available for 86 patients. Median AFEQT scores were lower in C2 (30.4; 17.2–51.9) vs C3 patients (56.5; 32.1–74.1; pConclusionThe QoL of patients awaiting AF ablation is impaired and AFEQT helps to identify patients at risk of admission, over and above physician assessment. COVID-19 influenced patients seeking medical attention with symptomatic AF when they normally would. Regular exercise is associated with better QoL in patients awaiting AF ablation.

TITLE PAGE TITLE : LEVEL OF BLOCKDESCRIPTION :Electrograms recorded from an electrophysiological study and ablation of manifest left lateral accessory pathway with demonstration of site of block during the case.