Comparison of first‐ and second‐generation leadless pacemakers in patients with sinus rhythm and complete atrioventricular block

Abstract

IntroductionThe efficacy and safety of leadless cardiac pacemakers (LPMs) as an alternative to conventional transvenous cardiac pacing have been largely reported. The first generation of the MicraTM transcatheter pacing system (VR; Medtronic) was able to provide single‐chamber VVI(R) pacing mode only, with a potential risk of pacemaker syndrome in sinus rhythm patients. A second‐generation system (AV) now provides atrioventricular synchrony through atrial mechanical (Am) sensing capability (VDD mode).ObjectiveWe sought to compare VR and AV systems in sinus rhythm patients with chronic ventricular pacing (Vp) for complete atrioventricular block.MethodsAll consecutive patients implanted with an LPM in our department for complete atrioventricular block were retrospectively screened. Patients with atrial fibrillation, sinus dysfunction, or Vp burden <20% at 1 month postimplantation were excluded. Patients were systematically followed with a visit at 1 month, and then at least once a year.ResultsA total of 93 patients—45 VR (2015–2020) and 48 AV (2020–2021)—were included. VR and AV patients had similar baseline characteristics, except for VR patients being older (80 ± 8 vs. 77 ± 9 years, p = 0.049). The mean Vp burden was 77% in the VR and 82% in the AV group (p = 0.38). In AV patients, the median AV synchronous beats rate was 78%, with 65% having a >66% rate. An E/A ratio <1.2 as measured on echocardiography was the only independent predictor of accurate atrial mechanical tracking (p = 0.01). One‐year survival rate was similar in both groups. Five patients in the VR and 0 in the AV group eventually developed pacemaker syndrome within 1 year post‐implantation (p = 0.02).ConclusionIn sinus rhythm patients with chronic Vp for complete atrioventricular block implanted with an LPM, the atrial mechanical sensing algorithm allowed significant atrioventricular synchrony in most patients and was associated with no occurrence of—otherwise rare—pacemaker syndrome.

Assessment of patient characteristics influencing the complexity of leadless pacemaker implantation

“…Although the number of patients eligible for LP has increased substantially with the introduction of LPs featuring atrial synchronization, careful evaluation of the procedural complexity is increasingly vital in the selection between LP and transvenous pacemakers to avoid complications. 19 , 20 , 21 Considering the present results, transvenous pacemakers may be an acceptable option for patients exhibiting RV dilation or severe TR. Nonetheless, it is noteworthy that although 2 cases in our study showed threshold elevation during or after LP implantation, no major complications, including pericardial effusion or cardiac tamponade, were reported.…”

Left atrial strain is a good predictor of atrio‐ventricular synchrony in leadless pacemaker pacing

“…17 Other authors found that a mitral E/A ratio lower than 1.2 appears to be an echocardiographic independent predictor of high AV synchrony. 14 According to our preliminary data morphological parameters such as LA APD and LAV, both as absolute values and indexed by body surface area, are related to different A4 vectorial sum. However, there is growing evidence that LA remodeling is not equal to LA enlargement alone as it includes LA changes at the molecular, cellular and tissue level even before LA enlargement.…”

“…Difficulty in AVS assessment is a recent topic of discussion and many efforts have been made to improve LCPM programming and achieve a higher rate of AVS. 13,14 Alongside this, we believe it is important to focus attention on the selection of patients, that could be crucial to optimize the choice of pacing device, based on echocardiographic parameters. Our data showed a statistically significant relationship between echocardiographic parameters, like APD, LAV and LAs, and atrial contraction signal The MASS and MASS2 study first demonstrated the feasibility of tracking mechanical atrial activity to provide AVS.…”

Different leadless pacemakers working in harmony (Aveir in the atrium/Micra AV2 in the ventricle) in a patient with dextrocardia and double outlet right ventricle after high‐risk infected device extraction

“…As this patient continues to become more active, further adjustment of atrioventricular synchrony can be performed with generation one Micra AV devices having a median synchrony of 78%, while generation two devices are likely to have a higher amount of synchrony. 6 Predicted longevities of devices may also account for choice of leadless option and/or other atrial pacing modalities.…”