[Evaluation of the sinoauricular conduction time: comparison of the recording of the sinus potential and Narula's method].

The sino-atrial conduction time, measured by Narula's method (SACTN) is compared to the direct sino-atrial conduction time measured by recording the sinus potential (SACTD) in 55 patients, 20 with normal sinus function and 35 with sinus dysfunction. In the absence of sinus dysfunction, SACTN and SACTD are not significantly different and a significant but mediocre correlation (r = 0.57) is observed between the two parameters. Major discordances between the two methods are seen in 4 patients. In cases with sinus dysfunction, there was no correlation between SACTD and SACTN; SACTN is close to SACTD in 12 patients, but much shorter in 11 patients and much longer in 10 patients. These discordances raise the problem of the penetration of the sinus node by the extrastimulus in Narula's method. This method does not seem capable of giving a reliable evaluation of the duration of sino-atrial conduction.