We studied the atrial electrophysiologic, histologic and mechanical characteristics in two groups of patients with (10 patients, Group 1) and without (5 patients, Group 2) spontaneous AF associated with the WPW syndrome. Only patients undergoing surgical dissection of the AP were selected. The following tests were performed: 1) electrophysiologic study before and after surgery to evaluate the electrical characteristics of the atria and AP, 2) recording of right and left atrial pressures and dimensions during RT to evaluate the contraction-excitation feedback mechanism, 3) histologic study of atrial specimens obtained at the time of surgery, and 4) evaluation of the mechanical properties of isolated atrial fibers. Patients of Group 1 showed shorter cycle length of the RT than patients of Group 2: no differences were observed in other electrophysiologic parameters. Induction of RT produced a significant increase of atrial pressures and dimensions in all patients, without differences between the two groups. Histologic abnormalities (mostly nonspecific, with interstitial fibrosis or active lymphocytic myocarditis) were found in 8 patients of Group 1 and in 2 patients of Group 2. Isolated atrial preparations showed Oscillatory Afterpotentials and Aftercontractions during Noradrenaline perfusion and electrical stimulation in two patients with and in none without history of AF. Our data suggest that, in patients with WPW syndrome, not only the electrophysiologic characteristics of the atria and AP, but also some structural atrial abnormalities and altered mechanical properties may be potentially involved in the development of AF.
|Number of pages||6|
|Journal||New Trends in Arrhythmias|
|Publication status||Published - 1992|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine