Cycle length in atrioventricular nodal reentrant paroxysmal tachycardia with observations on the lown-ganong-levine syndrome☆

Abstract Sixty-five patients with dual pathway atrioventrlcular (A-V) nodal reentrant paroxysmal tachycardia were studied. Of these 65 patients, 11 (17 percent) had a short P-R interval (0.12 second or less) and 3 (5 percent) had a short A-H interval (53 ms or less) during sinus rhythm, suggesting the Lown-Ganong-Levine syndrome. Frequency distribution analyses of P-R and A-H intervals In the 65 patients demonstrated continuous unimodal functions, suggesting a continuum of A-V nodal properties. Regression analyses of P-R and A-H (fast pathway) intervals versus cycle length of paroxysmal tachycardia revealed an r value of 0.11 and 0.10, respectively (not significant). The cycle length of paroxysmal tachycardia did not differ between the 11 patients with a short P-R Interval (370 ± 20 ms ) and the 54 patients without a short P-R interval (382 ±11 ms ). Regression analysis of the slow pathway A-H interval versus cycle length of paroxysmal tachycardia revealed an r value of 0.68 (p The cycle length of dual pathway A-V nodal reentrant paroxysmal tachycardia is a function of the slow pathway A-H Interval and not the P-R or A-H Interval during sinus rhythm. Identification of short P-R intervals in patients with A-V nodal reentrant paroxysmal tachycardia has little significance.