Introduction: Cardiac resynchronization therapy devices are routinely programmed on fixed atrioventricular delays (AVD) under resting conditions based on echocardiographic techniques. Whether this AVD also ensures optimal exercise hemodynamics, is unclear.
Methods: In order to compare fixed-AVD with rate-adaptive AVD, 100 patients with cardiac resynchronization therapy systems and sinus rhythm were randomized to fixed-AVD or adaptive-AVD. The patients then underwent bicycle ergometry with noninvasive hemodynamic monitoring. At rest and at peak exercise, stroke volume, cardiac output, and cardiac index were determined using "electrical velocimetry."
Results: There were no significant differences in clinical characteristics and baseline hemodynamic parameters between fixed or adaptive AVD. In patients randomized to adaptive AVD, a trend towards higher stroke volume, cardiac output, and cardiac index at peak exercise was encountered.
Conclusions: Based on the trend towards better exercise hemodynamics demonstrated by this pilot study, a randomized follow-up study with clinical end points appears to be justified to clarify this issue.
Copyright © 2012 Elsevier Inc. All rights reserved.