Temporal clustering of skin sympathetic nerve activity bursts in acute
myocardial infarction patients
Abstract
Introduction: The acute myocardial infarction (AMI) affecting the
autonomic nervous system (ANS) function has been affirmed in clinical
and basic research. We hypothesize that a high level of ANS regulation
in AMI patients could cause synchronized neural discharge (clustering
phenomenon) detected by non-invasive skin sympathetic nerve activity
(SKNA). Methods: Forty subjects, including 20 AMI patients and 20
non-AMI controls, participated in the study. The wide-band bioelectrical
signals (neuECG) were continuously recorded on the body surface for 5
minutes. The SKNA were signal processed to depict the envelope of SKNA
(eSKNA). By labeling the clusters, the subjects were separated into
non-AMI, non-cluster appearing (AMINCA) and cluster appearing (AMICA)
groups. Results: The average eSKNA was significant correlated with HRV
low frequency power (rho=-0.336) and high frequency power (rho=-0.372).
The cross-comparison results demonstrated the eSKNA is a credible
indicator to assess ANS in AMI patients. The frequency of cluster
occurrence was 0.01-0.03 Hz and the amplitude about 3 µV. The LF/HF
ratio of AMINCA (Median:3.959; Q1-Q3:1.840-6.562) revealed significantly
higher than AMICA (Median:1.877; Q1-Q3:1.483-2.413). The results
exhibited the SKNA clustering is a unique temporal pattern of ANS
synchronized discharge, which could regulate and help maintain the ANS
balance in AMI patients. Conclusion: This is the first study to identify
the SKNA clustering phenomenon in AMI patients. Such a synchronized
nerve discharge pattern could be detected with non-invasive SKNA
signals. The SKNA temporal clustering could be a novel biomarker to
classify the ANS regulation ability in AMI patients.