RESUMO
Introduction: The efficacy of de novo cardiac resynchronisation therapy (CRT) in patients with heart failure (HF), left ventricular systolic dysfunction (LVSD), and a broad QRS morphology is well established. However, the optimal stage for upgrading patients with existing pacemakers (PPMs) or implantable cardioverter-defibrillators (ICDs) and HF with high-burden right ventricular (RV) pacing remains uncertain. Thus, this multicentre retrospective analysis compared patients with pre-existing PPMs or ICDs who underwent CRT upgrades to investigate the appropriate stage for CRT implantation in these patients and to assess the validity of treating both PPM and ICD recipients under the same recommendation level in the current guidelines. Materials and Methods: A total of 151 participants underwent analysis in this study, comprising 93 upgrades to cardiac resynchronisation therapy with pacemaker (CRT-P) and 58 upgrades to cardiac resynchronisation therapy with defibrillator (CRT-D) across three centres in the UK. The aim of the study was to investigate the safety and efficacy of upgrading to CRT from an existing conventional pacemaker or an ICD in the context of high-burden RV pacing. The analysis was conducted separately for each group, assessing changes in echocardiographic parameters, functional New York Heart Association (NYHA) class, and procedure-related complications. Results: The PPM group had a higher percentage RVP burden compared to the ICD group. Post-upgrade, NYHA functional class and EF and LV volumes improved in both groups; however, the response to an upgrade from a pacemaker was greater compared to an upgrade from an ICD. Post-procedural complication risks were similar across the two subgroups but significantly higher compared to de novo implantation. Conclusions: Within the CRT-P subgroup, participants exhibited better responses than their CRT-D counterparts, evident both in echocardiographic improvements and clinical outcomes. Furthermore, patients with non-ischemic cardiomyopathy (NICM) were better responders than those with ischaemic cardiomyopathy. These findings suggest that international guidelines should consider approaching each subgroup separately in the future.
RESUMO
The extracellular matrix (ECM) scaffolds are considered a gold standard for the engineering of appropriate grafts used in regenerative medicine for tissue repair, and decellularization of myocardial tissue is one of the most studied processes for obtaining natural ECM to date. Decellularization methods, agents used, or treatment durations can be varied to optimize cardiac tissue decellularization parameters. In this work we performed a morphological and morphometric analysis of cardiac tissue subjected to decellularization protocols based on Sodium Deoxycholate (SD) or Sodium Lauryl Sulfate (SLS) to identify factors that allow optimization of single-detergent based protocols for cardiac ECM manufacturing. For this, Wistar rat hearts (n=10) were subjected to 5 different decellularization protocols (n=2) and then histologically processed to achieve H&E or Azan trichrome stained sections for the morphological and morphometric analysis of the obtained ECM. The results of this study showed that SLS alters the spatial distribution of cardiac ECM collagen fibers, and SD can be successfully used in tailoring single-based detergent decellularization protocols by appropriately adjusting the application times of hypo/hyperosmotic shocks, which increases the lytic action of the detergent, and the washing times for the efficient elimination of cellular residues.
