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Serial Measures of Sinoatrial and Atrioventricular Nodal Function in Ambulatory Patients
Author(s) -
LAHAYE STEPHEN,
SHEAHAN RICHARD,
DARLING DAVID,
DORIAN PAUL,
NEWMAN DAVID
Publication year - 1997
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.1997.tb04240.x
Subject(s) - medicine , ambulatory , refractory period , reproducibility , nodal , cardiology , effective refractory period , statistics , mathematics
We hypothesized that the outpatient assessment of SA and AV nodal (SAN, AVN) function could be a useful tool to determine the effectiveness of drugs and other treatments. We sought to examine the reproducibility, safety and ease of acquiring serial measurements of these parameters. Ten patients with permanent pacemakers underwent low current chest wall stimulation while their device was programmed to unipolar atrial triggered mode. Measurements at multiple conditioning drive train frequencies were obtained for: sinus nodal recovery time (SNRT); corrected sinus nodal recovery time (CSNRT); SA conduction time (SACT); AVN block cycle length (AVNBCL); and AVN effective refractory period (AVNERP). AVN function curves were also constructed. All studies were repeated after 2 weeks. Measures of sinus nodal and AVN function did not show significant differences between the two studies. The following coefficients of correlation were obtained: SNRT800, r = 0.79; CSNRT800, r = 0.71; SNRT600, r = 0.71; CSNRT600, r = 0.44; SACT, r = 0.75; AVNBCL, r = 0.98; AVNERP800, r = 0.55; and AVNERP600, r = 0.99. A VN function curves did not significantly differ between week 1 versus week 2 at conditioning drive trains of either 800 ms or 600 ms. These data suggest that serial noninvasive electrophysiological measures of AVN and SAN function are reproducible over 2 weeks. Using data in this study, estimates of the sample size necessary for the evaluation of the effects of investigational drugs on the SAN and AVN in future studies are possible.