Abstract 9373: Strict Rate Control Induced Sympathetic Augmentation in Patients with Atrial Fibrillation.
Prognosis of rate-control therapy in atrial fibrillation (AF) has been shown to be similar to that of rhythm-control therapy. However, the degree of optimal heart rate control in AF patient remains uncertain. Recent study indicated there were no significant difference in its symptoms and adverse events in AF patients between lenient and strict rate control. In this study, we measured single-unit and multi-unit muscle sympathetic nerve activity (MSNA) in 12 rate controlled AF patients, 6 more leniently rate controlled (HR 60 to 80 at rest) and 6 more strictly rate controlled (HR 40 to 60 at rest). Mean arterial pressure and left ventricular ejection fraction were not differing between two groups. Multiunit MSNA analysis did not differ between two groups, however, single-unit MSNA in more strictly rate controlled AF group was significantly greater than more leniently rate controlled AF group (63.2 +/− 14.1 vs 47.0 +/− 9.9 spikes/min, P<0.01, respectively). Multiple firing of single-unit MSNA within one cardiac interval was significantly augmented in more strictly rate-controlled AF group, during preceding long R-R interval and reduced diastolic pressure (p<0.05). These results indicate that multiple firing of single-unit MSNA increases during reduced diastolic arterial pressure in AF patients, and strict rate control induced sympathetic augmentation within one cardiac interval by arterial baroreflex system, which might an important mechanism for excessive sympathoexcitatory response.
- © 2010 by American Heart Association, Inc.