Autonomic modulation of ventricular rate in atrial fibrillation

Abstract

This study investigated the changes in R-R interval in 23 patients (11 men and 12 women; mean age 61 yr) with persistent atrial fibrillation in response to several provocative maneuvers including active postural change, Valsalva maneuver, handgrip, and rhythm-controlled respiration. Averaged R-R intervals were shortened immediately after postural change (from 797 +/- 35 ms supine to 677 +/- 27 ms standing; P < 0.01) and recovered to the 90% level within 100 s. During Valsalva strain and handgrip, mean R-R intervals were significantly shortened (from 737 +/- 37 ms sitting to 697 +/- 38 ms in Valsalva and from 773 +/- 68 ms sitting to 701 +/- 58 ms in handgrip; both P < 0.01). During rhythm-controlled respiration, only two cases (10.5%) showed power peaks in spectrograms of moving-window-averaged R-R intervals at the frequency corresponding to respiration rhythm. The ventricular response to atrial fibrillation is influenced by an increase in sympathetic tone and a decrease in parasympathetic tone but is not necessarily influenced by the increase in parasympathetic dominance. These results suggest that even in atrial fibrillation patients, the autonomic nervous system modulates the ventricular rate via the atrioventricular node and atrial tissue.

Respiratory Systolic Pressure Variability During Atrial Fibrillation and Sinus Rhythm

“…In 1920, Kilgore 1 reported respiratory oscillations in 6 of 9 patients with AF and, in 1989, Rawles et al 3 demonstrated the same phenomenon in 14% of patients by means of cosinor analysis. Chandler and Trewby 4 and Nagayoshi et al 5 found that only a small percentage of patients showed respiratory modulation of heart rate during AF (10.5% and 18%, respectively) but, although these are the only studies that used spectral techniques, they have the major limitation that respiration was not measured. 33 The presence of a peak in the R-R interval spectrum at a similar respiratory rate does not necessarily imply a relation with breathing; furthermore, to verify the relation between 2 signals, it is necessary to perform crossspectral analysis, as shown in Figure 4.…”

“…Few studies have investigated the respiratory oscillations of ventricular rhythm during AF, [1][2][3] and only 2 4,5 have made use of spectral analysis. These last 2 studies reported the presence of respiratory arrhythmia during AF in a small percentage of patients, but none measured respiration as a factor of analysis.…”

Ventriculophasic Modulation of Atrioventricular Nodal Conduction in Humans

“…Two recently published studies have demonstrated that rapid fluctuations of vagal tone can contribute to the irregularity of the ventricular response during atrial fibrillation. 29,30 Although the baroreflex was not investigated directly, it is reasonable to expect that ventriculophasic modulation of AV nodal conduction contributes to the complex dynamics of AV nodal function during atrial fibrillation.…”

Signal processing of intracardiac recordings for the evaluation of propofol effects during atrial fibrillation.

“…Some recent data suggest that the chronic fibrillating atrium is more under sympathetic than vagal control [277,278], but other studies have shown that adrenergic compounds do not affect the chronically fibrillating atrium [279]. The available data suggest that the anaesthetic used in patients with different types of AF increases the parasympathetic activation with different behaviors along the atrial regions, i.e.…”

“…The effects that propofol may induce on atrial activations during AF are not well understood yet. However, since some studies reflect the influence of the autonomic nervous system on AF [14,277], evidence suggests that propofol -as being an anaesthetic agentmay also affect the electrophysiological properties of AF. In fact, recent studies already report some modifications in both the dominant atrial rate and the organization of atrial activations with the administration of propofol [200,301].…”