A Real-world Experience of Atrioventricular Synchronous Pacing with
Leadless Ventricular Pacemakers
Abstract
Aims: The MicraTM transcatheter pacing system (TPS) (Medtronic) is the
only leadless pacemaker that promotes atrioventricular (AV) synchrony
via accelerometer-based atrial sensing. Data regarding the real-world
experience with this novel system are currently lacking. We sought to
characterize patients undergoing MicraTM -AV implants, describe
percentage AV synchrony achieved, and analyze the causes for suboptimal
AV synchrony. Methods: In this retrospective cohort study, electronic
medical records from 56 consecutive patients undergoing MicraTM -AV
implants at the Mayo Clinic sites in Minnesota, Florida, and Arizona
with a minimum follow-up of 3 months were reviewed. Demographic data,
comorbidities, echocardiographic data, and clinical outcomes were
compared among patients with and without atrial synchronous-ventricular
pacing (AsVP) ≥70%. Results: Fifty-six percent of patients achieved
AsVP ≥70%. Patients with adequate AsVP had smaller body mass indices, a
lower proportion of congestive heart failure and pulmonary hypertension.
Echocardiographic parameters and procedural characteristics were similar
across the two groups. Active device troubleshooting was associated with
higher AsVP. The likely reasons for low AsVP were persistent atrial
arrhythmias, small A4-wave amplitude, and inadequate device
reprogramming. Importantly, in patients with low AsVP, subjective
clinical worsening was not noted during follow-up. Conclusion: With the
increasing popularity of leadless PM, it is paramount for device
implanting teams to be familiar with common predictors of AV synchrony
and troubleshooting with MicraTM -AV devices.