Micra pacemaker in adult congenital heart disease patients: A case series

INTRODUCTION: Implantation of transvenous endocardial or epicardial pacemakers presents specific challenges in adult congenital heart disease (ACHD) patients. Micra leadless permanent pacemakers (Micra PPM) may overcome some of these difficulties. METHODS: Fifteen ACHD patients who underwent Micra PPM insertion were retrospectively evaluated. RESULTS: Males 53.3%. Mean age at study: 37.5 ± 10.7 years. Mean age at Micra PPM insertion: 35.5 ± 11.0 years. Mean follow-up so far: 2.0 ± 0.3 years. Concerning the ACHD patients, 6.7% had a simple defect, 66.6% had a moderately complex defect, 26.7% were complex. Four patients (26.7%) had a previous PPM implantation. Three patients (20%) had a systemic right ventricle. Two patients (13.3%) had a single ventricle physiology. Five (33.3%) had Trisomy 21. The most commonly used Micra PPM modality was single chamber ventricular pacemaker (73.3%). Mean threshold post implantation was 0.48 V [range: 0.25-1.13 V], while mean threshold at 6 months control was 0.60 V [range: 0.38-1.13 V] (p = ns). Mean R wave postimplantation was 10.3 V [range: 3.25-19.4 V], whilst mean R wave at 6 months follow-up was 10.1 V [range: 3.5-19.0 V] (p = ns). No major peri and postprocedural complications were encountered. CONCLUSIONS: since ACHD patients are living longer and surviving into adulthood, the incidence of conduction disorders continues to increase, as part of the natural history of some lesions or as early or late complication of surgery. The Micra leadless PPM can be successfully implanted in ACHD patients and have significant theoretical advantages. They should be considered when transvenous and epicardial pacing are either contraindicated or represent an otherwise suboptimal approach.