Single lead atrial synchronous ventricular pacing: a dream come true.

Single lead, atrial synchronous pacing systems were developed in the late 1970s. Clinical experience has demonstrated the need to position the "floating" atrial electrode in the mid-to-high right atrium and the need for a specially designed pulse generator (with very high atrial sensitivity) to provide a high quality and amplitude atrial electrogram for consistent sensing. A 12-year experience with different electrode configurations, from the first unipolar designed in 1980 to the most recent atrial bipolar electrodes, has confirmed the validity of the original concept and the long-term reliability of the single lead atrial synchronous pacing system, which can reliably produce long-term atrial sensing and ventricular stimulation in the presence of normal sinoatrial function.