Interatrial conduction (activation) times.

Left atrial electrograms were recorded simultaneously from sites located in the coronary sinus, right pulmonary artery and esophagus in order to determine and correlate the interatrial conduction times obtained from these locations. Ten patients with normal-sized atria and 16 patients with isolated left atrial enlargement were studied. A high correlation existed between the P wave duration and the interatrial conduction times obtained from the coronary sinus and pulmonary artery; good correlations were also found for the interatrial conduction times recorded from the pulmonary artery and esophagus correlated well with those recorded from the distal coronary sinus (the generally accepted standard for the indirect interatrial conduction time measurements). In addition to providing information on the mechanism of atrial arrhythmias, the electrograms obtained from the various indirect left atrial recording sites provide satisfactory quantification of interatrial conduction.