Comparison of cardiac function before and after Micra implantation using pool scintigraphy and myocardial work: A case report

Leadless pacemakers, specifically Micra (Medtronic), have recently become a preferred alternative to transvenous pacemakers for use in bradyarrhythmia. Problems with conventional transvenous pacemakers include wound infection, lead disconnection, and tricuspid valve dysfunction. While Micra has the advantage of not being associated with the aforementioned complications, there have been reports of cardiac injury during Micra implantation, which have raised safety concerns. Many reports have evaluated Micra safety, but its effect on cardiac function remains unclear. In an 85-year-old man with bradycardic atrial fibrillation, a heart rate of approximately 35 bpm, and symptoms of dizziness, we analyzed ventricular workload, ejection fraction of the left and right ventricles, and inter/intraventricular synchrony using cardiac blood pool scintigraphy and myocardial work. Micra was successfully implanted into the right ventricular septum via the left femoral vein. A follow-up, 2 days later, showed no major complications associated with Micra pacing threshold and impedance. At this time, there was no apparent worsening of heart failure. Micra implantation for bradycardic atrial fibrillation has the potential to improve left ventricular work efficiency without the loss of ventricular synchrony.