Simultaneous recordings of intrinsic cardiac nerve activity and skin sympathetic nerve activity from human patients during the postoperative period

Abstract

Background: Intrinsic cardiac nerve activity (ICNA) and skin nerve activity (SKNA) are both associated with cardiac arrhythmias in dogs.

Objective: The purpose of this study was to test the hypothesis that ICNA and SKNA correlate with postoperative cardiac arrhythmias in humans.

Methods: Eleven patients (mean age 60 ± 13 years; 4 women) were enrolled in this study. Electrical signals were simultaneously recorded from electrocardiogram (ECG) patch electrodes on the chest wall and from 2 temporary pacing wires placed during open heart surgery on the left atrial epicardial fat pad. The signals were filtered to display SKNA and ICNA. Premature atrial contractions (PACs) and premature ventricular contractions were determined manually. The SKNA and ICNA of the first 300 minutes of each patient were calculated minute by minute to determine baseline average amplitudes of nerve activities and to determine their correlation with arrhythmia burden.

Results: We processed 1365 ± 973 minutes of recording per patient. Low-amplitude SKNA and ICNA were present at all time, while the burst discharges were observed much less frequently. Both SKNA and burst ICNA were significantly associated with the onset of PACs and premature ventricular contractions. Baseline average ICNA (aICNA), but not average SKNA, had a significant association with PAC burden. The correlation coefficient (r) between aICNA and PAC burden was 0.78 (P < .01). A patient with the greatest aICNA developed postoperative atrial fibrillation.

Conclusion: ICNA and SKNA can be recorded from human patients in the postoperative period. The baseline magnitude of ICNA correlates with PAC burden and development of postoperative atrial fibrillation.

Keywords: Arrhythmias; Atrial fibrillation; Open heart surgery; Premature atrial contractions; Premature ventricular contractions.

Conflict of interest statement

Disclosures

Shien-Fong Lin and Peng-Sheng Chen have equity interest in Arrhythmotech, LLC.

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

Figures

Figure 1

Placement of the temporary pacing wires during surgery. At the end of the open heart surgery, two temporary pacing wires were threaded through the epicardial fat pad at the junction of the left superior pulmonary vein (LSPV) and left atrium (LA). The uninsulated portion of the temporary pacing wires went through the fat pad (yellow) near the LOM and the orifice of the LSPV. LAA, left atrial appendage; LOM, ligament of Marshall; LV, left ventricle.

Figure 2

Characteristics of human nerve activities. Panel A shows burst ICNA (red arrows) and SKNA (blue arrows) discharged intermittently in one patient. This patient has burst ICNA and SKNA present in only 0.4% and 0.6% of windows analyzed, respectively. Panel B shows burst ICNA and SKNA discharged simultaneously in another patient. This patient has burst ICNA and SKNA present in only 5.0% and 5.0% of windows analyzed, respectively. Note the sustained low-amplitude nerve activities were present at all time in both channels. Calibration bar = 3 sec.

Figure 3

Human nerve activities and PAC and PVC. Panel A shows burst ICNA (red arrows) and SKNA (blue arrows) discharges preceded an episode of PAC (arrowhead). Panel B shows burst ICNA and SKNA discharges preceded an episode of PVC (arrowhead). Calibration bar = 3 sec.

Figure 4

ICNA and postoperative atrial fibrillation (AF). Panel A shows burst ICNA (red arrow) at the onset of an episode of AF (red arrow). Insets show sinus with PAC bigeminy on the left and AF on the right. Sporadic SKNA (blue arrow) was present during AF. Panel B shows salvos of AF with clear sinus beat(s) (inset) in between. Burst ICNA (red arrows) occurred during but not at the onset of AF episodes (green arrows), suggesting passive activation from the real trigger elsewhere. Calibration bar = 5 sec.