RT-76
|
Non-invasive assessment of
atrial refractoriness during atrial fibrillation
|
|
|
S.B. Olsson, M. Holm, M.P.
Ingemansson, C. Meurling, S. Pehrson, L. Sörnmo*.
Depts of Cardiology and *Applied Electronics, Lund University, Lund, Sweden
|
|
Abstract
|
|
We have developed a non-invasive method for indirect
assessment of atrial refractoriness by estimation of atrial fibrillatory cycle length. The
method is applied in studies of interindividual and intraindividual variability as well as
during interventions with wellknown effects on atrial refractoriness.
In short, the dominating fibrillatory cycle length (DACL) of lead V1 was studied by
power/frequency analyses of QRST-reduced electrocardiograms in patients with chronic or
paroxysmal atrial fibrillation. The DACL, which ranged during rest between 120 and 195 ms,
exhibited a temporal variability of 1.7%, illustrating a good method reproducibility.
Intravenous injection of 80 mg dl-sotalol in 5 patients induced a 22% prolongation av
DACL, corresponding to 31 ms. Sympathetic stimulation by head-up tilt test in 12 patients
decreased DACL by 10 ms or 6% whilst vagal reaction during head-up tilt test in another
patient induced a 15 ms shortening of DACL.
We conclude that DACL has a marked interindividual variability and is highly
reproducible in the individual patient. Different influences from the autonomic nervous
system, as well as injection of dl-sotalol induces changes of DACL in the anticipated
direction. The clinical use of the method remains to be verified.
|
Key Words
|
|
Atrial fibrillation
atrial refractoriness, non-invasive assessment, dominating atrial cycle length,
dl-sotalol, sympathetic stimulation, vagal stimulation, OA
|
