Practical considerations, indications, and future perspectives for leadless and extravascular cardiac implantable electronic devices: a position paper by EHRA/HRS/LAHRS/APHRS

Cardiac implantable electronic devices (CIEDs) have become an integral part of brady- and tachy-arrhythmia management over the last seven decades. Most currently used legacy systems consist of a pacemaker (PM) and/or implantable cardioverter defibrillator (ICD) containing all the electronics implanted under the skin in the shoulder region, with a transvenous (TV) lead connecting the device to the heart for signal detection and cardiac stimulation and defibrillation. The TV lead is both the indispensable link to the PM or ICD, as well as the Achilles heel of the system. Over the last decade, this has led to the development of new CIED that can perform with a lead outside of the endovascular space or that do not require a lead at all. As randomized controlled data comparing this new generation CIED to traditional TV devices is scarce, international guidelines so far do not provide strong recommendations on their use. There is however a growing body of evidence supporting their efficacy and safety under various circumstances and in a wide variation of clinical scenarios. This position paper aims to review the underlying evidence and provide practical considerations for optimal use and patient selection for these CIED that are either currently or very close to becoming available. To provide guidance, the acknowledged format of the European Heart Rhythm Association will be used, as provided in Table 1. Scientific rationale of recommendationsa This categorization for our consensus document should not be considered as being directly similar to that used for official society guideline recommendations which apply a classification (I–III) and level of evidence (A–C) to recommendations. Leadless cardiac pacemakers (LCPMs) are an emerging alternative to TV-PM1–3 to reduce the complications related to TV leads and subcutaneous generator pockets.4–6 The LCPMs eliminate the risk of pocket infection and haematoma,1,2,7,8 as well as pneumothorax, lead dislodgement, infection, and fracture.9 Conversely, early LCPM studies have shown groin problems and myocardial perforation,1,2,10 patient management at the time of battery depletion is unresolved, first-generation devices only provided VVI-R pacing, while LCPM long-term outcome data are lacking. Details about various LCPM device and studies are provided in Table 2. In the LEADLESS II study,2 Nanostim LCPM implantation was successful in 95.8% of 526 patients, with major adverse events in 6.5% (perforation 1.5%, dislodgement 1.1%). Its successor AVEIR has been successfully implanted in 98% of 200 patients, with 3 cardiac tamponades requiring sternotomy in 2 patients.11 The Micra LCPM showed a 99.2% implant success in the investigational device exemption (IDE) and post-approval registry studies,1,3 and 41–63% lower complication rate (perforation 1.8 and 0.77%), with significantly lower device revision needed compared with a historical TV-PM cohort.9 In the recent Micra CED study,12 adjusted 30-day adverse event rates were similar (7.7 vs. 7.4%, P = 0.49), perforation was more frequent (0.8 vs. 0.4%, P 6 h after the procedure. In patients on vitamin K antagonists, implantation should be performed at an INR within a low therapeutic range at the physician’s discretion (Table 4).18–21 Facility, equipment, and implanting staff requirements CIED, cardiac implantable electronic device; EP, electrophysiologic; LCPM, leadless cardiac pacemaker. Micra (VR and AV) is CE approved for full-body 1.5 and 3T magnetic resonance imaging (MRI), Nanostim for full-body 1.5T MRI. The MRI was reported to cause heating of the LCPMs due to ‘antenna effect’; however, the increase in temperature was not clinically significant.22 The MRI scanning should be avoided within ≤6 weeks after implantation, or in case of elevated pacing threshold (>4.5 V at the nominal programmed pulse width).23 Both Micra and Nanostim need to be programmed to an MRI conditional mode prior to the scan. The patient’s ECG and peripheral pulse should be constantly monitored during MRI by experienced personnel, with an external defibrillator cardioverter with temporary pacing capabilities being immediately accessible. After the scan, the LCPMs should be interrogated and reprogrammed (Table 5). MRI scanning in LCPM recipients LCPMs, leadless cardiac pacemakers; MRI, magnetic resonance imaging. Nanostim magnet mode can be programmed ON (VOO mode at 90 b.p.m.) or OFF; however, Micra will not be affected a magnet is Therefore, Micra to be programmed to an mode prior to procedures that a risk of or staff must be for temporary or pacing is a of LCPM patients no evidence of or device Nanostim LCPM not have Micra can be to the which of rate device and review A Heart for via can be The and require In patients with Micra LCPM at 3 years, due to cardiac therapy threshold temporary battery depletion and PM The LCPM can be and a new device and are with all although with implantation and has been of Micra LCPM seems to be safe (Table and extraction of leadless devices ICD, implantable cardioverter LCPM, leadless cardiac pacemaker. a sheath or extraction of Micra and of Nanostim devices were at a of and after implantation, and complications in only data LCPM extraction in the first after implantation is and provided it is performed by an trained with for to LCPM can be programmed for by using The LCPM venous temperature for rate In rate and is adjusted to a rate rate was to = with optimal in of patients in a recent In cases, and be The new generation Micra mode by using the to signal may and has been in the of the may be useful in but no definitive criteria or at The and of ventricular at heart rate and rate and while the may due to To battery the the rate is the device in the only to to mode the rate is it is to this to in the more rather than mode (Table leadless pacing LCPM, leadless cardiac pacemaker. In the 2021 ESC for pacing and LCPM should be considered in patients without venous or a risk of device infection previous CIED infection and patients on The LCPM should be considered as an alternative to standard TV-PM, and using or TV-PM should be in patients with or to avoid and and PM The TV-PM and/or or system pacing should be in patients with a pacing and ventricular pacing rate heart and left ventricular ventricular that do not to an with and block or ventricular rate are optimal for The pacing has become an by of the but this while not This may be considered in patients with but with block a TV system is not considered The same may apply to patients with or block and a low ventricular pacing rate of The LCPM or TV systems may be considered in patients in single-chamber pacing not increase or cause in this of The to implant a TV-PM or LCPM should and with two or more risk for infection renal chronic use of of and may from the low risk for The LCPM implantation is in the of a mechanical to avoid of of the delivery system and/or device In an LCPM system may be in case of or or after to avoid and When considering implanting an LCPM, must the of TV leads and a device in subcutaneous the of the LCPM battery and the position in the patients could from TV leads a is but the device not perform pacing and the RV LCPM in the RV become at some in time or TV and LCPM may be A seems to patients about the these both as well as from a practical of In the of long-term LCPM implantation in the of not from circumstances that a of of the and an LCPM of about years, a of should be that conventional TV-PM should be in patients of or should not be considered for an LCPM, although patients with and/or may from a lower complication rate of LCPM (Table LCPM position on the underlying and clinical circumstances on CIED, cardiac implantable electronic device; of of pacing may over traditional cardiac The system is a CE approved system that is not available or at this The system delivery of leadless 3 the of the of a implanted over the in a space and to a generator which is in the The is implanted in the The system of a pacing signal from an existing pacing system to delivery of a of by the to the that this to the and system (reproduced with permission from right The and can be implanted in two or as a procedure. 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