Skin sympathetic nerve activity precedes the onset and termination of paroxysmal atrial tachycardia and fibrillation

Abstract

Background: Skin sympathetic nerve activity (SKNA) is useful for estimating sympathetic tone in humans.

Objective: The purpose of this study was to test the hypotheses that (1) increased SKNA is associated with the onset and termination of paroxysmal atrial tachycardia (AT) and atrial fibrillation (AF) and (2) sinoatrial node response to SKNA is reduced in patients with more frequent AT or AF episodes.

Methods: SKNA and electrocardiogram were recorded in 11 patients (4 men and 7 women; average age 66 ± 10 years), including 3 patients with AT (11 ± 18 episodes per patient) and 8 patients with AF (24 ± 26 episodes per patient).

Results: The average SKNA (aSKNA) 10 seconds before AT onset was 1.07 ± 0.10 μV and 10 seconds after termination was 1.27 ± 0.10 μV; both were significantly (P = .032 and P < .0001) higher than that during sinus rhythm (0.97 ± 0.09 μV). The aSKNA 10 seconds before AF onset was 1.34 ± 0.07 μV and 10 seconds after termination was 1.31 ± 0.07 μV; both were significantly (P < .0001) higher than that during sinus rhythm (1.04 ± 0.07 μV). The aSKNA before onset (P < .0001) and after termination (P = .0011) was higher in AF than in AT. The sinus rate correlated (P < .0001) with aSKNA in each patient (average r = 0.74; 95% confidence interval 0.65-0.84). The r value in each patient negatively correlated with the number of AT and AF episodes (r = -0.6493; 95% confidence interval -0.8990 to -0.08073; P = .0306).

Conclusion: Increased SKNA was observed both at the onset and termination of AT and AF. Patients with more frequent AT and AF episodes had a weak correlation between sinus rate and aSKNA, suggesting sinoatrial node remodeling by tachycardia.

Keywords: Arrhythmia; Autonomic nervous system; Sick sinus syndrome; neuECG.

Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

SKNA characteristics before onset and after termination of AT in patient #10, who has 32 episodes of AT fulfilling the inclusion criteria. Signals were high bandpass filtered from 500 Hz-1000 Hz to reveal SKNA and from 0.5 Hz-150 Hz to reveal ECG. iSKNA was obtained by integrating the voltage of digitized data over 100 ms windows. (A) Multiple episodes of SKNA bursts (black arrows) were present within 30 s (double headed arrows) prior to AT onset. Heart rate acceleration (green arrows) associated with SKNA burst (blue arrows) was observed prior to AT termination (red dotted line). This phenomenon was present in all 32 AT termination episodes analyzed for this patient. SKNA continues to be elevated during the 30 s after termination. SKNA was also increased during premature atrial contraction (arrowhead). (B) Similar findings in a separate AT episode, consistent with (A).

Figure 2

NeuECG recording of an AT episode from patient #1. SKNA is slightly elevated prior to (blue arrows) and at the onset of AT (downward black arrows). A short burst of SKNA (blue arrows) was observed prior to termination, but was not associated with HR acceleration. There was no SKNA elevation after termination. Each double headed arrow indicates 30 s.

Figure 3

NeuECG recording of AF onset in patient #7. (A) SKNA is significantly increased prior to AF onset (black arrows). Double arrows indicate 10 s. (B) Similar findings in a separate AF episode of the same patient. SKNA is significantly increased prior to AF onset (black arrows). Two beats of premature atrial contractions preceded the onset (blue arrows), also associated with higher SKNA.

Figure 4

NeuECG recording of AF termination. (A) Significant increase in SKNA was observed in patient #7 before and after spontaneous termination of AF (black arrows). The double arrows indicate 10 s. A premature atrial contraction was recorded after termination of AF (blue arrow). (B) Similar to (A), increased SKNA was observed before and after termination of AF in patient #8.

Figure 5

Characteristics of aSKNA and HR before, during last 10 s, and after AF or AT episodes. aSKNA before onset (red), during final 10 s (green) and after termination (blue) of both AT and PF episodes is greater than that of sinus rhythm (black) (p

Figure 6

Correlation between aSKNA and HR and its relationship to frequency of AT or AF. (A) aSKNA and HR positively correlated with each other in all 11 patients. (B) Correlation coefficient of each patient is inversely correlated to the frequency of AT or AF episodes in the same patient. The more frequent a patient has AT or AF episodes, the less sensitive their HR is to sympathetic activation as detected by neuECG via skin. The outlier (black arrow) is from patient #10, who had > 100 short runs of AT but only 32 was ≥ 10 s and were included in the analyses. If we included all short burst of AT in the analyses, then his r value may not be lower than expected.