DOI: 10.5061/dryad.rfj6q57kw
title: Electrocardiography and vital signs recorded in patients with subarachnoid hemorrhage

description: This dataset includes electrocardiography and vital signs recording in
 patients with subarachnoid hemorrhage during their stay in the intensive
 care unit. Participants in this clinical trial (NCT04557618) were
 randomized to receive either the transcutaneous auricular vagus nerve
 stimulation (taVNS) or Sham treatment. The goal of this study is to study
 the cardiovascular effects of taVNS in patients with subarachnoid
 hemorrhage.
description: A 3-lead system was used for electrocardiograms (ECG). ECG
 signals, sampled at 500 Hz, and other vital signs, such as blood pressure,
 sampled at 1 Hz, were recorded from the Intellivue patient monitor
 (Philips®, Netherlands) using vitalDB software. We removed all personally
 identifiable information from the dataset, such as names and contact
 details. Please see reference 1 for a detailed description of the study
 protocol. Following randomization, enrolled patients
 underwent 20 minutes of either taVNS or sham stimulation twice daily
 during their stay in the ICU. During treatment periods, a portable
 transcutaneous electrical nerve stimulation (TENS) device (TENS 7000
 Digital TENS Unit, Compass Health Brands, OH, USA) was connected to the
 patient’s left ear using two ear clips. For taVNS treatments, these ear
 clips were placed along the concha of the ear, while for sham treatments,
 the clips were placed along the earlobe to avoid stimulation of the
 auricular vagus nerve from tactile pressure. For the taVNS group,
 stimulation parameters were selected based on values reported in prior
 studies that sought to maximize vagus somatosensory evoked potentials
 while avoiding the perception of pain: 20 Hz frequency, 250 µs pulse
 width, and 0.4 mA intensity30. The stimulation was not perceptible for the
 patients. No electrical current was delivered during sham treatments. For
 both groups, the TENS device was connected to the patient and a bedside
 recording computer. The computer recorded continuous ECG and vital signs,
 including blood pressure, temperature, respiration rate, peripheral
 perfusion index, intracranial pressure, and arterial blood pressure. The
 collection of intracranial pressure and arterial blood pressure data
 varied, being dependent on the treatment protocol assigned by the clinical
 team, and thus was not uniformly available for all patients throughout the
 study. Any empty values in the .csv files indicate that the data was
 unavailable at the given time. For example, blood pressure measurements
 were taken according to the physicians' schedule and were not
 available at every time point. 1.    Huguenard, A. et
 al. Non-invasive Auricular Vagus nerve stimulation for Subarachnoid
 Hemorrhage (NAVSaH): Protocol for a prospective, triple-blinded,
 randomized controlled trial. PLOS ONE vol. 19 e0301154 (2024).
description: # Electrocardiography and vital signs recorded in patients with
 subarachnoid hemorrhage
 [https://doi.org/10.5061/dryad.rfj6q57kw](https://doi.org/10.5061/dryad.rfj6q57kw) ## Description of the data and file structure ### Files and variables #### File: df\_hrv\_sum.csv **Description:** This file includes heart rate variability and heart rate measured from 24-hour ECG recordings. To calculate cardiac metrics, we first applied a 0.5 Hz fifth-order high-pass Butterworth filter and a 60 Hz powerline filter on ECG data to reduce artifacts. We detected QRS complexes based on the steepness of the absolute gradient of the ECG signal using the Neurokit2 software package. R-peaks were detected as local maxima in the QRS complexes. P waves, T waves, and QRS complexes were delineated based on the wavelet transform of the ECG signals proposed by Martinez J. P. et al. ##### Variables * subj: anonymous subject id * treatment: 1 means active taVNS * research day: day 0 means the first day when the patient is allocated into either intervention or control groups. * research_date: the exact date of the recording  * csi: cardiac sympathetic index (a.u.) * cvi: cardiac vagal index (a.u.) * lfnu: normalized low-frequency power (a.u.) * hfnu: normalize high-frequency power (a.u.) * sdnn: standard deviation of normal RR intervals (ms) * pnni_50: The proportion derived by dividing nni_50 (The number of interval differences of successive RR intervals greater than 50 ms) by the total number of RR intervals. * rmssd: root mean square of successive difference (based on nn intervals, ms) * mean_hr: heart rate (beat per minute) * n_ectopic_beats: the number of ectopic beats * n_ectopic_beats: the number of rr interval outliers * mean_qt: qt interval (ms) * mean_qtc_bazett: corrected QT interval (a.u.) * n_long_qtc_bazett: the number of long QT (clinical definition) * pct_long_qtc_bazett: percentage of long QT over the total number of QT * n_short_qtc_bazett: the number of short QT (clinical definition) * pct_short_qtc_bazett: percentage of short QT over the total number of QT ### **File: df\_bp\_sum.csv** **Description:** This file includes vital signs measured each day during the patients' hospitalized stay in the ICU. ##### Variables * mean_ABP_MEAN: average ambulatory blood pressure (mmHg) * treatment: 1 means intervention * research day: day 0 means the first day when the patient is allocated into either intervention or control groups. * num_samples_ABP_MEAN: The number of samples for ABP on this day * mean_ABP_SYS: systolic ambulatory blood pressure (mmHg) * std_ABP_SYSL: standard deviation of  systolic ambulatory blood pressure (mmHg) * num_samples_ABP_SYS: The number of samples for systolic ABP on this day * mean_ABP_DIA: diastolic ambulatory blood pressure (mmHg) * std_ABP_DIA: standard deviation of  diastolic ambulatory blood pressure (mmHg) * num_samples_ABP_DIA:  The number of samples for diastolic ABP on this day * mean_ICP_MEAN: average intracranial pressure (mmHg) * std_ICP_MEAN: standard deviation of intracranial pressure (mmHg) * num_samples_ICP_MEAN:  The number of samples of ICP on this day * mean_RR: average respiration rate (number of respiration per minute) * std_RR: standard deviation of respiration rate (number of respiration per minute) * num_samples_RR:  The number of samples of RR on this day * mean_NIBP_SYS: systolic non-invasively measured blood pressure  (mmHg) * std_NIBP_SYS: standard deviation of systolic non-invasively measured blood pressure (mmHg) * num_samples_NIBP_SYS:  The number of samples of mean_NIBP_SYS on this day * mean_NIBP_DIA: diastolic non-invasively measured blood pressure (mmHg) * std_NIBP_DIA: standard deviation of diastolic non-invasively measured blood pressure (mmHg) * num_samples_NIBP_DIA:  The number of samples of mean_NIBP_DIA on this day * mean_NIBP_MEAN: average non-invasively measured blood pressure (mmHg) * std_NIBP_MEAN: standard deviation of non-invasively measured blood pressure (mmHg) * num_samples_NIBP_MEAN: The number of samples of mean_NIBP_MEAN on this day * mean_PLETH_PERF_REL: average peripheral perfusion index (a.u.) * std_PLETH_PERF_REL: standard deviation of peripheral perfusion index (a.u.) * num_samples_PLETH_PERF_REL: The number of samples of mean_PLETH_PERF_REL on this day #### **File: bp\_feature.zip** **Description:**  it includes the recording of vital signs for 6-minute time windows every three minutes for each subject. * rel_time: time relative to mid-night (minute) * condition: there are three possible conditions, including baseline, aligned_to_stim_onset, and aligned_to_stim_offset. 'baseline' means the measurement at least 1 hour prior to the intervention or after the intervention. * research day: day 0 means the first day when the patient is allocated into either intervention or control groups. * am_pm: morning or afternoon * ABP_DIA: diastolic ambulatory blood pressure (mmHg) * ABP_SYS: systolic ambulatory blood pressure (mmHg) * ABP_MEAN: mean ambulatory blood pressure (mmHg) * ICP_MEAN: mean intracranial pressure (mmHg) * RR: average respiration rate (number of respiration per minute) * NIBP_SYS: systolic noninvasively measured blood pressure (mmHg) * NIBP_DIA: diastolic noninvasively measured blood pressure (mmHg) * NIBP_MEAN: mean noninvasively measured blood pressure (mmHg) * PLETH_PERF_REL: peripheral perfusion index (a.u.) #### File: baseline\_hrv\_shortterm.csv **Description:**  This file includes cardiac measurement for 6-minute time windows every three minutes for each subject. * research day: day 0 means the first day when the patient is allocated into either intervention or control groups. * timestamp: exact time for the center of the time window * csi: cardiac sympathetic index * cvi: cardiac vagal index * lfnu: normalized low-frequency power * hfnu: normalize high-frequency power * total_power: total spectral power * rmssd: root mean square of successive difference (based on nn intervals) * mean_hr: heart rate * sdnn: standard deviation of normal RR intervals * nni_50: Number of interval differences of successive RR-intervals greater than 50 ms. * pnni_50: The proportion derived by dividing nni_50 (The number of interval differences of successive RR intervals greater than 50 ms) by the total number of RR intervals. * n_ectopic_beats: the number of ectopic beats * n_ectopic_beats: the number of rr interval outliers * mean_qt: qt interval * mean_qtc_bazett: corrected QT interval * time_since_midnight: as indicated in the variable name * subject_id: anonymous patient ID ## Code/software Codes and scripts are available in [https://github.com/GanshengT/taVNS_SAH](https://github.com/GanshengT/taVNS_SAH).