Background Changes in sympathetic and vagal neural regulatory mechanisms play a crucial role in alterations of cardiac electrical properties and in promoting the occurrence of atrial fibrillation (AF). Spontaneous baroreflex sensitivity (BRS) is useful diagnostic tool for assessment of autonomic cardiovascular regulation however until now there have been no data concerning its role as a trigger of AF onset.
Aim of the present study was assessment of baroreflex function in patients with and without late AF recurrence and identification of independent predictors of late AF recurrence during 6-month observation.
Material and methods The study population consisted of 60 patients who experienced at least one AF episode during the last 3 months. All subjects underwent beat-to-beat blood pressure (BP) monitoring. Baroreflex function was assessed in the frequency domain BRS (alpha coefficient, modulus of transfer function-H), and in the time domain (sequence technique). The study end point involved late recurrence of AF or the end of 6-month follow-up.
Results During the follow-up 29 (48.3%) patients experienced late AF recurrence. The group with AF recurrence as compared with the sinus rhythm maintenance group was characterized by increased spontaneous BRS assessed using all 3 methods (alpha LF: 7.7 ± 4.1 vs. 4.8 ± 1.8 ms/mm Hg,p = 0.002; alpha HF: 22.0 ± 17.2 vs. 10.7 ± 5.0 ms/mm Hg, p = 0.002; H-LF: 6.0 ± 3.3 vs. 3.8 ± 1.5 ms/mm Hg, p = 0.002; H-HF: 17.3 ± 13.4 vs. 8.6 ± 3.9 ms/mm Hg, p = 0.002; weighted sequence method - wSeq 9.5 ± 4.2 vs. 5.8 ± 3.3, p = 0.001). The Cox regression analysis revealed that independent predictors of AF were only BRS indices and AF duration history.
Conclusions Patients with late atrial fibrillation recurrence are characterized by augmented parasympathetic modulation. Indices of spontaneous baroreflex sensitivity are independent predictors of late atrial fibrillation recurrence. The noninvasive method of spontaneous baroreflex sensitivity assessment based on beat-to-beat blood pressure monitoring appears to have a clinical value as a promising method for early identification of patients at higher AF recurrence rate and thus enabling prevention of further episodes.
Arterial Hypertension 2007, vol. 11, no 6, pages 483-497.