Validation of inter-atrial conduction time measurement by means of echo-Doppler

Little is known about the correlation between the inter-atrial conduction time (IACT) measured at the electrophysiology laboratory and the interval measured from the beginning of the electrocardiographic P wave to the initiation of the A wave in the mitral Doppler signal (P-A interval). IACT can be assessed by means of echo-Doppler. We studied 21 patients who were referred to our arrhythmia clinic for evaluation of supraventricular tachycardia. During the electrophysiological study, the IACT was measured from the first rapid deflection of the A wave recorded with the high right atrial catheter to the A wave recorded with the coronary sinus catheter. An independent observer measured the P-A interval. Both the electrophysiological and echo-Doppler measurements were corrected for heart rate. P-A interval was slightly longer than IACT (83.36 +/- 23.91 vs 80.77 +/- 24.11 msec; p = 0.042), but a very good correlation was found between both measurements (r2 = 0.94). IACT can be non-invasively assessed by measuring the P-A interval.