Speckle Tracking Echocardiography in Pediatric and Congenital Heart Disease Patients with the Micra™ Leadless Pacemaker.

Right ventricular pacing can cause electrical and mechanical dyssynchrony, potentially leading to pacemaker-induced cardiomyopathy (PICM). This pilot study evaluates speckle tracking echocardiography for the early detection of subclinical left ventricular dysfunction in pediatric and congenital heart disease patients with Micra™ leadless pacemakers (Medtronic, Minneapolis, MN, USA). We analyzed echocardiograms of eight patients (mean age, 15 years; 63% women) with Micra™ pacemakers at implant and 1 month and 1 year post-implant. Data of interest included demographics, pacemaker position, ejection fraction (EF), shortening fraction, and global longitudinal strain (GLS). The pacing percentages varied from <0.1% to 100%, with three patients having burdens of >20%. The mean GLS was -17.99, and the mean EF was 59.6%. A higher EF correlated mildly with more-negative GLS values (<i>r</i> = 0.288; <i>P</i> = .218), and greater pacing percentages correlated with poorer GLS values (<i>r</i> = -0.381; <i>P</i> = .097). In summary, GLS has the potential to identify myocardial dyssynchrony, which may have the potential to support the early detection of PICM. Further research with larger cohorts and longer follow-up is needed to validate these findings.