TENS Impact Heart Rate Via Vagus Activity
TENS Impact Heart Rate Via Vagus Activity
Transcutaneous electric nerve stimulation (TENS) is widely used for the treatment of adhesive
 capsulitis, nevertheless, its potential impact on heart physiology has not been well
 established.

 The investigator explored if TENS at shoulder region affect heart rhythm and the machinery
 involved.

 Subjects were stratified into groups received sham stimulation (TENS-S) and TENS on either
 the right (TENS-R) or left (TENS-L) shoulder. A built-in waveform for treating adhesive
 capsulitis with a maximal tolerable intensity below the pain threshold was applied to
 subjects form a commercial TENS equipment for 5 min. The electrocardiogram (ECG) and heart
 rate (HR) were continuously recorded and the ECG was off-line transferred into power spectrum
 for analysis.
Study design This study complied with the Declaration of Helsinki, and all protocols were
 approved by the ethics committee of Taoyuan General Hospital, Ministry of Health and Welfare,
 Taoyuan, Taiwan. All the participants gave written informed consent before experiments. 32
 subjects (20-51 years old) were included in the statistical analysis. Participants were
 eligible if they have cardiovascular illnesses, major mental conditions, or severe
 inflammation. Participants were allocated to groups that received sham stimulation (TENS-S)
 and TENS on the right and left shoulder (TENS-R and TENS-L, respectively).

 ECG and HR recordings Using a monitor lead, electrocardiogram (ECG) was recorded through
 electrodes connected to a recording system with a sampling rate of 5,000 samples/sec. The ECG
 and the HR calculated by a built-in rate meter were continuously recorded and displayed on a
 monitor. For TENS caused marked artifacts in ECG tracings, HR derived from ECG were confirmed
 off-line by manual examination.

 TENS stimulation To mimicking clinical scenarios, a commercial TENS equipment was used
 throughout this study. A built-in waveform recommended for treating capsulitis in the user's
 manual was used for stimulation (triple pulses with 1 ms pulse durations separated by a 1 ms
 intervals were ramps up and down between 2 to 10 Hz within 20 sec for 3 min and then ramps up
 from 10 to 200 Hz within 20 sec and kept at 200 Hz for 2 min; supplementary data 1). The
 current intensity was adjusted to the maximal tolerance level below the pain threshold. A
 pair of stimulating electrode was placed in the front of the should at the level of the
 sternal notch at about 2 finger-width from the mid-clavicle line, and a pair of dispersive
 electrode was placed at the back of shoulder opposite to the stimulating electrodes.
 Participants kept a stationary supine position and was asked to refrain from moving during
 recording. Before the stimulation, there was an equilibrium period for at least 10 min, and
 then the recording started. TENS was turned on for 5 min at 5 min after the baseline
 recording, and the recording continued until 10 min after the offset of stimulation.
 Parameters of the sham stimulation was identical to TENS stimulation on the right shoulder
 excepting the equipment was left un-powered.
Inclusion Criteria:

 healthy adult

 Exclusion Criteria:

 hypertension diabetes heart diseases neurological diseases othe medical problem