Atherosclerosis is a chronic inflammatory disease of the vessel wall in which reactive oxygen species (ROS) 3 -mediated activation of redox-sensitive transcription pathways modulates atherosclerotic plaque progression. Increased adhesion molecule expression and remodeling of extracellular matrix are among the major changes caused by the activation of redoxsensitive signaling pathways. NADPH oxidases are critical determinants of the redox status of the vessel wall and play a critical role in the pathophysiology of atherosclerosis.

The purpose of this paper is to summarize the need, feasibility, safety, legality, and ethical perspectives of pacemaker reutilization in low- and middle-income countries (LMICs). It will also describe, in-depth, Project My Heart Your Heart (PMHYH) as a model for pacemaker reuse in LMICs. The primary source of the discussion points in this paper is a collection of 14 publications produced by the research team at the University of Michigan and its collaborative partners. The need for pacemaker reutilization in LMICs is evident. Numerous studies show that the concept of pacemaker reutilization in LMICs is feasible. Infection and device malfunction are the main concerns in regard to pacemaker reutilization, yet many studies have shown that pacemaker reuse is not associated with increased infection risk or higher mortality compared with new device implantation. Under the right circumstances, the ethical and legal bases for pacemaker reutilization are supported. PMHYH is a proof of concept pacemaker donation initiative that has allowed funeral home and crematory directors to send explanted devices to an academic center for evaluation and re-sterilization before donation to underserved patients in LMICs. The time is now to pursue large-scale studies and trials of pacemaker reuse for the betterment of society. PMHYH is leading the way in the effort and is poised to conduct a prospective randomized, non-inferiority, multicenter study to confirm the clinical efficacy and safety of pacemaker reuse, for clinical and legal support.

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Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) is the gold standard for imaging myocardial viability. An important application of LGE CMR is the assessment of the location and extent of the myocardial scar in patients with ventricular tachycardia (VT), which allows for more accurate identification of the ablation targets. However, a large percentage of patients with VT have cardiac implantable electronic devices (CIEDs), which is a relative contraindication for cardiac magnetic resonance imaging due to safety and image artifact concerns. Previous studies showed that these patients can be safely scanned on 1.5 T scanners provided that an adequate imaging protocol is adopted. Nevertheless, imaging patients with a CIED result in metal artifacts due to the strong frequency off-resonance effects near the device; therefore, the spins in the surrounding myocardium are not completely inverted, and thus give rise to hyperintensity artifacts. These artifacts obscure the myocardial scar tissue and limit the ability to study the correlation between the myocardial scar structure and the electro-anatomical map during catheter ablation. In this study, we developed a modified inversion recovery technique to alleviate the CIED-induced metal artifacts and improve the diagnostic image quality of LGE images in patients with CIEDs without increasing scan time or requiring additional hardware. The developed technique was tested in phantom experiments and in vivo scans, which showed its capability for suppressing the hyperintensity artifacts without compromising myocardium nulling in the resulting LGE images.

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