First-in-Human Study of the Circle Safe System for Diaphragm Response Monitoring During Pulmonary Vein Ablation

Overview

The objective of this first-in-human study is to evaluate the safety and performance of the Circle Safe System in subjects undergoing pulmonary vein ablation for atrial fibrillation. The main questions it aims to answer are: * Can the Circle Safe System consistently stimulate the phrenic nerve and record a stable electrical response from the diaphragm? * Can it reliably display changes in the diaphragm's response during ablation? * What device-related or procedure-related medical problems occur during the study? There is no comparison group. All participants will undergo their planned pulmonary vein ablation while the Circle Safe System is used during treatment of the right pulmonary veins. Participants will: * Complete standard assessments before the procedure * Have the Circle Safe catheter placed in the superior vena cava during the ablation procedure * Have their phrenic nerve stimulated and their diaphragm response monitored using the Circle Safe System * Be evaluated for device-related and procedure-related safety events through hospital discharge

During right pulmonary vein ablation, the Circle Safe catheter is advanced through the venous system and positioned in the superior vena cava. Its distal electrodes provide diagnostic stimulation of the right phrenic nerve, while its proximal electrodes record the resulting diaphragmatic compound motor action potential (CMAP). The recorded signal is transmitted to the Circle Safe System Console, which displays the CMAP waveform and automatically compares its amplitude with a baseline measurement obtained before ablation. This allows changes in diaphragmatic activity to be monitored throughout treatment of the right pulmonary veins. The Circle Safe System is a diagnostic monitoring aid. It does not deliver ablation energy, modify the ablation procedure, or replace standard phrenic nerve monitoring methods used by the physician. Device function, signal stability, procedural use, and any device deficiencies or adverse events are documented during the study.