Potential feasibility of a novel over‐the‐wire microelectrode catheter for recording coronary sinus electrograms in patients with cardiac resynchronization therapy devices

The placement of an electrode catheter into the coronary sinus (CS) is important for differentiating multiple atrial tachycardias (ATs). Based on its high selective performance in placement into small veins, inserting a novel over‐the‐wire 2.7Fr microcatheter (EPstar Fix AIV; Japan Lifeline) into the CS may be feasible even in patients implanted with a cardiac resynchronization therapy device.