LAUSR

Over the past four decades, Moore’s law has accurately predicted that computing power will double every 2 years. Yet, while today’s handheld calculators possess more processing ability than the original NASA Apollo Guidance Computer, the basic design and function of a VVI pacemaker have not changed significantly since the 1960s. Nevertheless, transvenous pacemakers have proven to be an indispensable treatment option for patients with symptomatic and often life‐threatening bradycardia. This therapy, however, is not without risk. Amongst other issues, pocket hematoma, pneumothorax, hemothorax, lead dislodgement, infection, and vascular compromise are significant causes of morbidity in patients with transvenous devices. Aimed at reducing associated risks by dramatic changes in pacing delivery, the recent development of leadless pacemakers represents one of the most significant design innovations in cardiac pacing since the very first implantable device. Paradoxically, however, the evolution from a modular and expandable transvenous system to a fixed single chamber device is, in some respects, taking a step backward in our programming ability. To date, two separate products have been evaluated and brought to market, the Nanostim LP (Abbott, Abbott Park, IL) and the Micra Transcatheter Pacemaker (Medtronic, Minneapolis, MN). While initial results are quite promising, understanding the appropriate application and limitations of transcatheter pacing systems (TPS) will be essential for the safe adoption of this relatively new technology. In this issue of the journal, Tjong et al studied the health‐related quality of life (HRQoL) impact of a TPS. Similar to the standard pacemaker therapy, patient‐rated HRQoL was found to be significantly improved 3 months after the implantation of the device. This effect was studied on both a physical and a mental component scale. The significant improvement persisted after 12 months of follow‐up and was most pronounced in the role‐physical domain. Furthermore, most patients were either very satisfied or satisfied with their recovery, appearance, and level of activity after implantation, and a significant majority of implanting physicians rated the degree of activity restriction as either equally or less restrictive (96%) than the traditional pacemaker therapy. These quality of life (QoL) improvements with TPS should not be undervalued. The decision to implant a pacemaker is often based heavily on the acute rhythm disturbance, with the long‐term impact of the device delivery system as more of a secondary afterthought. Beyond QoL, this study by Tjong et al also highlights the importance of patient selection. Quite notably, during the 12‐month follow‐up period, there were a total of 52 deaths in the study group (7%). While these deaths were not attributed to complications from either device implantation or dysfunction, patient selection may have contributed to the increased mortality. In this study group, for instance, nearly 18% of the patients had congestive heart failure, a condition in which RV pacing has been associated with worse outcomes, prompting the need for additional investigation. As described previously, current indications for permanent single ventricular pacing with a leadless device include atrial tachyarrhythmias not expected to benefit from atrioventricular (AV) synchrony, sinus bradycardia with low anticipated pacing burden, low level of baseline physical activity, limited life expectancy, and compromised vascular access. In a recently published real‐world registry of 795 patients who underwent Micra TPS implantation, a majority had permanent or persistent atrial tachycardia (57.7%). Of these 795 patients, nearly 21% had more than one condition that precluded placement of a transvenous system (compromised vascular access, history or risk of infection, cancer, thrombosis, a need to preserve veins for hemodialysis, and valvular issues). In addition, there were only 13 major complications in these patients, with the most common (6 events) being related to the groin access site. Notably, there was one device dislodgement (without embolization) as compared with zero dislodgements in the initial study group. Additional 12‐month monitoring data for the Micra device showed a significantly lower rate of complications compared with traditional intravascular devices, while also demonstrating adequate pacing thresholds, R‐wave sensing,