Implantable Cardiac Monitors: Evolution Through Disruption

Abstract

ABSTRACT. Syncope and stroke are commonly seen in clinical practice, and the diagnostic workup is often time-consuming and costly and may increase resource utilization in the health-care system. The use of implantable cardiac monitors (ICMs) in syncope evaluation has been well studied, but their use in cryptogenic stroke evaluation and anticoagulation management in patients with atrial fibrillation (AF) is still emerging. The standard workup of the syncope patient or those at risk for a possible cardioembolic stroke includes the utilization of external cardiac monitors; however, these devices cannot provide long-term arrhythmia assessment, whereas ICMs can now last up to three years, increasing the possibility of arriving at a diagnosis. Recent studies have shown that ICM use may shorten the time to diagnosis associated with AF, which may affect the prescribed treatment plan, thereby reducing the risks of further stroke. Long term and on a larger scale, this could potentially reduce overall health-care costs, but more studies are needed to confirm whether ICMs can positively decrease such costs and improve patient care. Still, these devices have become smaller and more reliable; additionally, they are now equipped with enhanced diagnostic capabilities, reducing the likelihood of physicians being confronted with an overwhelming amount of data, and supplying them with actionable items to improve patient care. With this growth, ICMs have in effect become a disruptive technology, as their applications in clinical practice continue to grow. Additional studies are warranted to investigate the safety and efficacy of their potential uses.

Changes In R-wave Amplitude At Implantation Are Associated With Gender and Postures: Observations From The Confirm Rx™ Body Posture and Physical Activity Study

“…Seminal studies such as RAST (Randomized Assessment of Syncope Trial) [20], PICTURE (Place of Reveal in the Care Pathway and Treatment of Patients with Unexplained Recurrent Syncope) [7], and CRYSTAL-AF[6] trials revealed that ICMs were capable and more successful in detecting AF in patients with syncope (30-36% increased detection rate over a period of ~10 months) and cryptogenic stroke (6-fold increased detection by 12 months) than conventional monitoring. Despite advances in ease-of-implant, remote-monitoring and data collection capabilities, ICMs are not devoid of RWA sensing irregularities [21]. These sensing insu ciencies and related inaccuracies in rhythm detection can delay the diagnosis of arrythmias in syncope and cryptogenic stroke as demonstrated in several small studies reporting the effect of body postures, activity and site of implantation on signal quality received from external or subcutaneous ECG [15,19,[22][23][24].…”

Changes in R-wave amplitude at implantation are associated with gender and orientation of insertable cardiac monitor: observations from the confirm Rx™ body posture and physical activity study

“…Seminal studies such as RAST (Randomized Assessment of Syncope Trial) [ 20 ], PICTURE (Place of Reveal in the Care Pathway and Treatment of Patients with Unexplained Recurrent Syncope)[ 7 ], and CRYSTAL-AF [ 6 ] trials revealed that ICMs were capable and more successful in detecting AF in patients with syncope (30–36% increased detection rate over a period of ~ 10 months) and cryptogenic stroke (sixfold increased detection by 12 months) than conventional monitoring. Despite advances in ease-of-implant, remote-monitoring and data collection capabilities, ICMs are not devoid of RWA sensing irregularities [ 21 ]. These sensing insufficiencies and related inaccuracies in rhythm detection can delay the diagnosis of arrythmias in syncope and cryptogenic stroke as demonstrated in several small studies reporting the effect of body postures, activity and site of implantation on signal quality received from external or subcutaneous ECG [ 15 , 19 , 22 – 24 ].…”

Stream Processing Architectures for Continuous ECG Monitoring Using Subsampling- Based Classifiers

“…In specific, we chose the classification of AF in single-lead ECG signals, i.e., the PhysionNet 2017 challenge [38], due to the following aspects. Single-lead ECG data provide a realistic assumption for the input in mobile ECG sensor devices, e.g., smartwatches or implantable cardiac monitors [14]. Here, the attachment of leads (and even the lead positions) is determined by convenience and device form factor, which is viable for daily human activity with minimal compromises.…”

“…for a lifetime of more than one week [13]. In the extreme case, implantable cardiac monitoring systems [14] are expected to operate continuously for 2-3 years with a current budget of around 10 µA [15]. These tight power constraints severely limit what function the cardiac monitoring system is capable of realizing.…”