Introduction: Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting more than 4% of the world’s population. Furthermore, the vulnerable substrate underlying atrial cardiomyopathy remains far from being understood. Atrial cardiomyopathy is a highly complex and heterogeneous disease that occurs in the context of various clinical backgrounds, which explains the heterogenous success of established atrial ablation strategies such as pulmonary vein isolation. Here we developed a new interventional method for the treatment of AF using a tattooing procedure of silver nanowires in the atria to create circular lines of increased conductivity to prevent irregular electrical propagation.

Purpose: In a translational study, we tested a newly developed interventional method to terminate AF by injecting lines of silver nanowires to increase tissue conductivity.

Methods: The developed tattoo method was tested in vivo using an established large animal AF model of the domestic pig. Pigs (n = 10) with atrial fibrillation were either treated with right atrial tattoo lines using a transmural injection procedure of silver nanowires as closed lines in the atrium or got a sham treatment with saline injections. Over 21 days, AF was induced and monitored (AF burden) by an intracardiac dual-chamber device with a biofeedback induction algorithm. Initially and before final termination, conventional electrophysiological investigation and atrial 3D mapping, echocardiography and epicardial multi electrode array (MEA) measurements were performed. Following the 21 days observation period, the heart was extracted and freshly isolated atrial cardiomyocytes were subjected to cellular electrophysiological, molecular and histochemical characterization. Electrophysiological data was used for in silico modelling of arrhythmia termination and wave propagation. The study protocol was approved by the animal ethics committee.