Implantation of a novel insertable cardiac monitor: preliminary multicenter experience in Europe

Insertable cardiac monitors (ICMs) serve as crucial tools for the long-term monitoring of patients with known or suspected cardiac arrhythmias. Over time, the indications for ICM usage have broadened [1‐3], reflecting advancements in device miniaturization, simplification of subcutaneous insertion procedures, enhancement of arrhythmia detection algorithms, and the incorporation of novel functionalities [4]. The LUX-Dx™ (Boston Scientific, Marlborough, MA, USA) is a novel ICM, incorporating dual-stage arrhythmia detection algorithms and remote programming capabilities. While prior studies have examined the remote programming of this device within prospective and real-world settings [4, 5], there remains a paucity of literature exploring the implantation experience of the LUX-Dx™ ICM, particularly in European contexts. Therefore, the aim of this investigation was to provide a comprehensive description of the LUX-Dx™ implantation experience in Europe during its initial year of commercial use.

In this study, we present the initial experience of LUX-Dx™ ICM implantation in clinical practice in Europe. The implantation procedure was safe and straightforward and yielded favorable outcomes in terms of system functionality, as well as satisfaction reported by both operators and patients. The patient cohort exhibited diverse clinical characteristics. Consistent with previous observational studies [5‐7], the indications for ICM implantation varied, with unexplained syncope being the most common indication, supported by robust evidence and established recommendations [1, 2].

The majority of procedures were conducted by physicians in electrophysiology laboratories, although positive experiences have been reported with procedures performed by nurses and in alternative settings [8‐12]. Local anesthesia was used in almost all cases. Antibiotic prophylaxis was administered before the procedure in 56% of cases, consistent with previous literature where prophylaxis rates ranged from 0 to 50% [7, 13, 14]. Surface ECG mapping was conducted before a minority of procedures (30%). The efficacy of the applied anatomically based placement approach was confirmed by the low rate of intraoperative ICM repositioning required after signal verification, consistent with previous studies [1, 15]. Despite being an analysis of initial implantations, procedural times were fast, consistent with, or even shorter than those reported for previous systems (typically ranging from 5 to 9 min) [7, 13, 14, 16]. Procedural times exhibited consistency across patient groups, and shorter values when ECG mapping was omitted or sutureless systems for wound closure were used. After an initial experience with the system, a further reduction in procedural times was also observed. Sensing parameters at implantation were optimal, remained stable until pre-discharge, and were not influenced by patient characteristics or indications, consistent with findings from other ICM studies [17]. R-wave amplitudes were higher in the younger patients, in agreement with previous studies that showed better R-wave sensing in pediatric patients, being the amplitude inversely proportional to the patient body surface area [18]. Furthermore, P-wave visibility was favorable compared to values reported for other systems [19]. Surface ECG mapping did not yield improved sensing parameters, whereas positioning the device parallel to the sternum resulted in slightly enhanced P-wave visibility. This finding has been previously shown with ICMs with long sensing vectors, although significant differences were not detected [20]. The consistency of results across varying indications and with advancing age is reassuring and particularly significant as it has been demonstrated that the utility of ICMs increases with age, with new diagnoses more frequently made and important treatment changes more frequently triggered in older patients [6].

Operator feedback on incision and insertion tools, as well as on the sensing verification App and remote management system for enrollment and programming, was positive. Patients reported very good ease of use of the App, with over 90% not experiencing pain during the procedure and over 98% reporting no pain or paresthesia post-implantation. This contrasts favorably with discomfort reported after implantation of previous ICMs with long sensing vectors (no relevant post-implantation pain in 47% and no sustained paresthesia in 51% of patients) [13].

The implementation of remote monitoring for ICMs presents the challenge of a high volume of transmissions and frequent misdiagnoses [21]. Consequently, there has been an effort to develop improved arrhythmia detection algorithms aimed at reducing false-positive detections [22]. Moreover, there is increasing emphasis on the programming of ICMs, with the recent Expert Consensus Statement on Practical Management of the Remote Device Clinic [23] recommending tailored alert programming based on clinical indications. The LUX-Dx™ ICM automatically customizes detection parameters based on the specific reason for monitoring set at enrollment. This aligns with recommendations to tailor programming, without requiring manual deviation from the nominal parameters set, as observed in the present study. Additionally, symptom recording was frequently enabled in our patients, as also recommended for assessing symptom-rhythm correlation [23]. The guidelines also suggest reprogramming in cases of frequent false positives or nonactionable alerts. Indeed, strategic reprogramming can effectively reduce transmission volumes [8], albeit potentially necessitating additional office visits. In response, remote programming capabilities have been introduced in modern ICMs to alleviate alert burden without the need for in-person consultations, aligning with recommendations that in-office visits are unnecessary for the ongoing care of ICM patients [23]. The real-world use of ICM remote programming has been recently described, reviewing data from more than 8000 patients in the USA with the LUX-Dx™ ICM [5]. The analysis showed that 24% of devices were reprogrammed, with 82% of reprogramming events occurring remotely, mostly within the first 30 days post-implantation, suggesting that remote programming may enhance clinical efficiency and patient care without additional workload. In the present analysis, the device was set to detect connection loss of at least 7 days in almost all patients, with notifications sent to the patient’s mobile device to ensure consistent connectivity. High levels of remote monitoring were previously demonstrated with the LUX-Dx™, minimizing transmission failures and maintaining continuous connectivity throughout the monitoring period [4]. This addresses issues of transmission delays reported with previous systems [24, 25] and is also important to potentially reduce transmission volume. In fact, guidelines allow the elimination of scheduled transmissions in cases of uninterrupted connectivity [23]. However, our study revealed that such scheduled transmissions are still often programmed every 30 days. Therefore, eliminating these transmissions could significantly reduce the overall volume of transmissions.

LUX-Dx™ implantation appears efficient and straightforward, with favorable post-implantation sensing values across all indications and patient characteristics and associated with positive feedback from operators and patients.