An active fixation quadripolar left ventricular lead for cardiac resynchronization therapy with reduced postoperative complication rates.

BACKGROUND: The rate of left ventricular (LV) lead displacement after cardiac resynchronization therapy (CRT) remains high despite improvements in lead technology. In 2017, a novel quadripolar lead with active fixation technology became available in the UK. METHODS: This was a retrospective, observational study analyzing device complications in 476 consecutive patients undergoing successful first-time implantation of a CRT device at a tertiary center from 2017 to 2020. RESULTS: Both active (n = 135) and passive fixation (n = 341) quadripolar leads had similar success rates for implantation (99.3% vs. 98.8%, p = 1.00), although the pacing threshold (0.89 [0.60-1.25] vs. 1.00 [0.70-1.60] V, p = .01) and lead impedance (632 [552-794] vs. 730 [636-862] Ohms, p < .0001) were significantly lower for the active fixation lead. Patients receiving an active fixation lead had a reduced incidence of lead displacement at 6 months (0.74% vs. 4.69%, p = .036). There was no significant difference in the rate of right atrial (RA) and right ventricular (RV) lead displacement between the two groups (RA: 1.48% vs. 1.17%, p = .68; RV: 2.22% vs. 1.76%, p = .72). Reprogramming the LV lead after displacement was unsuccessful in most cases (successful reprogramming: Active fix = 0/1, Passive fix = 1/16) therefore nearly all patients required a repeat procedure. As a result, the rate of intervention within 6 months for lead displacement was significantly lower when patients were implanted with the active fixation lead (0.74% vs. 4.40%, p = .049). CONCLUSION: The novel active fixation lead in our study has a lower incidence of lead displacement and re-intervention compared to conventional quadripolar leads for CRT.

Hepitopes: A live interactive database of HLA class I epitopes in hepatitis B virus.

Increased clinical and scientific scrutiny is being applied to hepatitis B virus (HBV), with focus on the development of new therapeutic approaches, ultimately aiming for cure. Defining the optimum natural CD8+ T cell immune responses that arise in HBV, mediated by HLA class I epitope presentation, may help to inform novel immunotherapeutic strategies. Therefore, we have set out to develop a comprehensive database of these epitopes in HBV, coined 'Hepitopes'. This undertaking has its foundations in a systematic literature review to identify the sites and sequences of all published class I epitopes in HBV. We also collected information regarding the methods used to define each epitope, and any reported associations between an immune response to this epitope and disease outcome. The results of this search have been collated into a new open-access interactive database that is available at http://www.expmedndm.ox.ac.uk/hepitopes. Over time, we will continue to refine and update this resource, as well as inviting contributions from others in the field to support its development. This unique new database is an important foundation for ongoing investigations into the nature and impact of the CD8+ T cell response to HBV.

Approaches to augment vascularisation and regeneration of the adult heart via the reactivated epicardium.

Survival rates following myocardial infarction have increased in recent years but current treatments for post-infarction recovery are inadequate and cannot induce regeneration of damaged hearts. Regenerative medicine could provide disease-reversing treatments by harnessing modern concepts in cell and developmental biology. A recently-established paradigm in regenerative medicine is that regeneration of a tissue can be achieved by reactivation of the coordinated developmental processes that originally formed the tissue. In the heart, the epicardium has emerged as an important regulator of cardiac development and reactivation of epicardial developmental processes may provide a means to enable cardiac regeneration. Indeed, in adult mouse hearts, treatment with thymosin ß4 and other drug-like molecules reactivates the epicardium and improves outcomes after myocardial infarction by inducing regenerative paracrine signalling, neovascularisation and de novo cardiomyocyte production. However, there are considerable limitations to current methods of epicardial reactivation that prevent direct translation into clinical practice. Here, we describe the rationale for targeting the epicardium and the successes and limitations of this approach. We consider how several recent advances in epicardial biology could be used to overcome these limitations. These advances include insight into epicardial signalling and heterogeneity, epicardial modulation of inflammation and epicardial remodelling of extracellular matrix.