Direct recording of sinus node potentials using electrode catheter techniques.

Direct recording of sinus node (SN) potentials using electrode catheter techniques is feasible and may be achieved in 50-86% of patients. It takes 15-30 min using commercially available catheters. However, obtaining stable recordings is often difficult, necessitating direct contact of the distal electrode with the endocardial area underlying the sinus node. There is a wide range in sinoatrial (SA) intervals (30-150 ms) obtained, and an overlap exists between patients with normal and abnormal SN function. Consequently, measurement of the SA interval alone may not be a reliable tool for diagnosing SN dysfunction. However, direct SN recordings have a theoretic value, allowing differentiation of disorders of SA conduction from disorders of the impulse generation.