title: Cycle length in atrioventricular nodal reentrant paroxysmal tachycardia with observations on the Lown-Ganong-Levine syndrome.
abstract: Sixty-five patients with dual pathway atrioventricular (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 less than 0.001). 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.
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology; D001283:Atrioventricular Node / Q000503:physiopathology*; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D013577:Syndrome; D013614:Tachycardia, Paroxysmal / Q000503:physiopathology*; D013997:Time Factors; D014927:Wolff-Parkinson-White Syndrome / Q000503:physiopathology