result in the need to undergo lead extraction, and therefore the concept of leadless pacemakers has been developed Different device companies have developed leadless pacing models that have been implanted in adults with varying results The pacemaker system is delivered via the transcatheter approach and all electrodes are fully contained in a single unit that is implanted in the RV apex Serious device-related complications ranged from 6.7% to 18.6%.201 Currently, leadless pacemaker implantation is not routinely performed and there are no studies in children Compatibility of Magnetic Resonance Imaging There is a growing population with implanted electronic cardiac devices and a parallel demand for MRI For most implanted hardware there is a largely theoretical concern that exposure under the strong electromagnetic fields encountered during MRI may result in shifting of the device, heating of the hardware, changes in the programmed settings enabling asynchronous erratic rapid pacing, triggered tachyarrhythmia therapies, or pacing inhibition Device companies have undergone labor-intensive trials to develop MRI-safe devices for the growing needs of these patients Although some of the more recent devices (implantable loop monitors, pacemakers and ICDs) are MRI-conditional, risk factors remain Protocols have been developed and center on utility shielding, filters, and bipolar leads to mitigate electronic interference; device programming protocols; and image tips and guidelines to prevent artifact across the area of interest Careful selection of the right test for the right patient with the right implanted hardware is paramount in promoting safety and strategies to optimize care.202 It is important to remember that MRI-conditional devices include not just the generator but also the active leads as well as chronically abandoned leads that may be endocardial, epicardial, or a combination of the two A recent guideline publication by the Heart Rhythm Society focused on recommendations targeting the clinical aspects of safety with MRInonconditional and conditional systems.203 Pacemaker Syndrome The consequences of atrial contraction against closed AV valves during ventricular systole create transient increases in atrial pressure The symptoms that relate to such a physiologic effect include fatigue, exercise intolerance, a sensation of fullness, dyspnea, and headache; they have fallen under the broader heading of pacemaker syndrome This occurs in up to 20% of patients with single-chamber pacing from loss of AV synchrony, but is not restricted to singlechamber devices.204 These symptoms can sometimes by improved by adjusting the programmed settings of AV intervals and rate-adaptive features If symptoms persist, other options may be explored, including upgrading to a dual-chamber system in those with a single-chamber system Routine Follow-Up After pacemaker implantation, ongoing careful follow-up is necessary This will vary to some degree; however, common practice is to evaluate new implants in a patient at 2 weeks and at 3 months Following this, visits can be spaced out to every 3 to 12 months, either in person or with remote monitoring Initial postimplant evaluation is done to rule out complications such as pneumothorax, hemothorax, pacemaker pocket hematoma, cardiac perforation, pleural or pericardial effusion lead dislodgement, diaphragmatic stimulation, infection, pacemaker malfunction, central venous thrombus, lead fracture, insulation break, or Twiddler syndrome, although these are rare Remote monitoring is beneficial in decreasing the need for in-office evaluation and has multiple other benefits, including improved care and convenience to families Subsequent to the acute postimplant time period, it is valuable always to reevaluate the patients pacing requirements while testing the device and to be open to altering previous programmed modes, since the patient's clinical status may change Routine evaluation should include assessment of battery status, pacing thresholds, pulse width, sensing function, the integrity of the lead, any sensed or recorded events, and surveillance for any occult arrhythmias Restrictions for Patients With Implanted Devices Risk factors involved in living a sedentary life surpass the risk factors of possible damage to the device hardware Providers should encourage patients be active and stay healthy Decisions regarding the level of activity should be individualized toward patients with underlying heart disease, underlying rhythm disturbances, and the possibility of the developing a tachyarrhythmia Participation in organized team sports should be an informed collaborative decision between the cardiologist, parents, and patient In the case of patients who are pacemaker dependent, meaning that they do not have an adequate underlying rhythm to sustain their cardiac output, activity restrictions are needed Varying opinions to protect this vulnerable population involve increasing safety margins, adding an additional ventricular lead, or placing biventricular systems, but there are no clear data to guide this decision