The frequency spectrum of sympathetic nerve activity and arrhythmogenicity in ambulatory dogs
Xiao Liua b, Yuan Yuana c, Johnson Wonga, Guannan Menga d, Akira Ueokaa e, Leanne Woiewodskia, Lan S. Chenf, Changyu Sheng, Xiaochun Lih, Shien‐Fong Lina i, Thomas H. Everetta, Peng‐Sheng Chena b j✉
- aKrannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
- bCedars-Sinai Medical Center, Los Angeles, California
- cDepartment of Cardiothoracic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- dDepartment of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
- eDepartment of Cardiovascular Medicine, Okayama University Graduate School of Medicine Dentistry and Pharmaceutical Sciences, Okayama, Japan
- fDepartment of Neurology, Indiana University School of Medicine, Indianapolis, Indiana
- gRichard and Susan Smith Center for Outcomes Research in Cardiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
- hDepartment of Biostatistics, Indiana University School of Medicine & Richard M. Fairbanks School of Public Health, Indianapolis, Indiana
- iInstitute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan
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Abstract
Background: Sympathetic nerve activity, heart rate (HR), and blood pressure (BP) all have very low frequency (VLF), low frequency (LF), and high frequency (HF) oscillations. Objective: The purpose of this study was to test the hypothesis that the frequency spectra of subcutaneous nerve activity (ScNA), stellate ganglion nerve activity (SGNA), HR, and BP are important to cardiac arrhythmogenesis. Methods: We used radiotransmitters to record SGNA, ScNA, HR, and BP in 6 ambulatory dogs and determined the dominant frequency and paroxysmal atrial tachyarrhythmias (PATs) episodes in 3-minute windows over a 24-hour period. Results: The frequency spectra determined in ScNA reflected that in SGNA. HF oscillations were present in both ScNA and SGNA at all time but could be overshadowed by the much larger LF and VLF burst activities. The dominant frequency could occur in any of the 3 frequency bands. There were circadian variations with more frequent occurrences of HF oscillations at night. HF oscillations in HR and BP matched HF oscillations in SGNA and ScNA. PATs occurred only when dominant frequencies of SGNA and ScNA were in the LF and VLF bands. Conclusion: HF oscillations in BP and HR correlate with HF oscillations in sympathetic nerve activity and are present at all time. HF oscillations can be overshadowed by the much larger LF and VLF burst activities. PATs occur only when LF or VLF, but not when HF, is the dominant frequency. The frequency spectra determined in ScNA reflect that in SGNA.