The Role of Implantable Cardiac Monitors in Atrial Fibrillation Management

Abstract

Continuous heart rhythm monitoring using implantable cardiac monitors (ICMs) for atrial fibrillation (AF) management is steadily increasing in current clinical practice, even in the absence of an established indication provided by international guidelines. The increasing use of such devices is mainly associated with recent technological improvements including miniaturization, easier implant procedures, and remote monitoring, all of which make this strategy continuously more appealing and promising. For these and other reasons, ICMs have been proven to be a safe and highly effective tool for detecting AF episodes. However, ICMs are not the best option for every patient, as limitations exist. Therefore, it is imperative to weigh the possible benefits against the potential limitations of using these devices when deciding individualized patient care.

Keywords: Atrial fibrillation; Continuous monitoring; Implantable Cardiac Monitor; Loop recorder; Subcutaneous electrocardiogram.

Figure 1.. Examples of subcutaneous electrocardiogram (subECG) from ICMs identified as AF episodes by the automatic algorithm. (A) True positive AF episode (B) False positive AF episode due to undersensing of premature ventricular contractions (C) False positive AF episode due to oversensing of P waves (D) False positive AF episode due to oversensing of noise. First-line ICM markers (black ticks); second-line ICM subECG; third-line time (seconds).

Figure 2.. Example of ICM implantation with the corresponding final fluoroscopy image and the subcutaneous electrocardiogram (subECG) detected by the device.

Figure 3.. The typical location of an ICM is in the left parasternal area of the chest over the fourth-fifth intercostal space. There are two recommended inclinations: device parallel to the sternum (B) and device at a 45° angle to the sternum (A).