NCT Number: NCT07719777
During general anesthesia for surgery, doctors use an electrocardiogram (ECG)-a simple heart monitor-to check for problems like poor blood flow to the heart or irregular heartbeats. Normally, ECG stickers (called electrodes) go on both shoulders and the left side of the belly, right outside the heart area, to get clear readings.
But for shoulder surgery, these spots are in the way of the operation, so doctors often place them elsewhere, like on the breastbone instead of the shoulder. This can give fuzzy or wrong results, missing key changes in the patient's heart-good or bad-during surgery.
To fix this and better watch heart health in shoulder surgery patients, this study tests different ECG sticker spots: the usual ones, the common backup (like on the breastbone), and a new idea-placing them near both temples. Researchers hope to find which setup gives the most accurate heart readings to keep patients safer.
Interested in participating?
Request Info19 year–65 year
All sexes
Interventional
Not applicable
Dongguk University Il-san Hospital, Goyang-si, Gyeonggi-do, South Korea
Background and Rationale Electrocardiogram (ECG) monitoring is essential during general anesthesia to assess heart rate, arrhythmias, and myocardial ischemia, alongside blood pressure. Standard Lead II, derived from limb leads placed on the torso (both clavicles below and left anterior superior iliac spine, outside the heart boundary), aligns best with the heart's electrical axis for accurate rhythm and ischemia detection. However, in shoulder surgeries like arthroscopic rotator cuff repair, surgical incisions overlap these sites, forcing electrode relocation (e.g., to the sternum instead of the shoulder). This inward shift distorts ECG signals, potentially missing normal or abnormal heart changes during surgery. To address this, modified Lead II placements are needed for reliable cardiac surveillance in shoulder surgery patients.
Study Overview This prospective, single-group interventional study evaluates the performance of two modified ECG Lead II configurations compared to the standard during general anesthesia for non-shoulder surgeries (to simulate placement feasibility). The modifications test alternative sites for the left shoulder electrode: sternum center (modified Sternum-Chest Lead II, mSC2) versus temple (modified Temple-Chest Lead II, mTC2). Left-side versions are assessed post-induction in supine position; right-side versions post-surgery. Outcomes focus on ST segment morphology similarity (visual and quantitative) to ensure modified leads maintain diagnostic accuracy without artifacts.
Methods Summary Eligible adults (19-65 years) scheduled for general anesthesia in non-shoulder sites undergo standard monitoring (ECG, NIBP, SpO2) per institutional protocols. After induction and hemodynamic stabilization, three ECG configurations are recorded simultaneously using Vital Recorder software (VitalDB, Republic of Korea) for at least 10 noise-free waves: (1) Standard Lead II; (2) Left mSC2 (sternum, right shoulder, left iliac spine); (3) Left mTC2 (left temple, right shoulder, left iliac spine). Post-surgery, right-side mSC2 and mTC2 are added. Recordings capture preoperative ST segment status (normal/abnormal). Blinded assessors (two researchers, third for ties) evaluate ST similarity visually; quantitative area differences use R/RStudio.
Statistical Considerations Sample size (n=84, 10% dropout) is calculated via McNemar test for paired comparisons, stratified by ST status (normal: 38 pairs; abnormal: 46 pairs), yielding 80% power at $\\alpha=0.05$ based on pilot data. Analysis: Stratified McNemar for agreement; R for area differences.
Safety and Ethics Modifications involve brief additional recordings with no added risk beyond standard care. IRB-approved (Dongguk University Ilsan Hospital); informed consent obtained. Data anonymized (case numbers); stored securely for 3 years per regulations.
Healthy volunteers accepted: No
Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
Exclusion criteria
Standard ECG Lead II monitoring: Three electrodes placed on both clavicles below and left anterior superior iliac spine (outside heart boundary). Recorded simultaneously post-induction for at least 10 noise-free waves using Vital Recorder software to establish baseline ST segment morphology during general anesthesia."
Other names: mSC2, mTC2
Modified Sternum-Chest Lead II ECG (mSC2): Electrode relocated to sternum center (replacing left shoulder), with right shoulder and left anterior superior iliac spine. Left-side version recorded post-induction; right-side post-surgery. Assesses ST segment similarity to standard for accurate ischemia detection in anesthesia.
Modified Temple-Chest Lead II ECG (mTC2): Electrode relocated near temple (replacing left shoulder), with right shoulder and left anterior superior iliac spine. Left-side version recorded post-induction; right-side post-surgery. Evaluates ST segment morphology match to standard to enhance cardiac monitoring reliability.
Time frame: Periprocedural
This measure evaluates and compares which of the two modified Lead II configurations (Left modified Temple-Chest Lead II [Lt-mTC2] vs. Left modified Sternum-Chest Lead II [Lt-mSC2]) aligns more accurately with the Standard Lead II. To ensure objectivity, two blinded researchers will independently compare the ECG waveform shapes and determine which modified lead shows superior visual similarity to the Standard Lead II. In cases of disagreement or tie, a third researcher will re-evaluate the waveforms for the final decision. Evaluators will be strictly blinded to the identity of the specific leads being assessed.
Time frame: Periprocedural
This measure evaluates and compares which of the two right-side modified Lead II configurations (Right modified Temple-Chest Lead II [Rt-mTC2] vs. Right modified Sternum-Chest Lead II [Rt-mSC2]) aligns more accurately with the Standard Lead II post-surgery. Two blinded researchers will independently compare the ECG waveform shapes and determine which right-side modified lead shows superior visual similarity to the Standard Lead II. In cases of disagreement or tie, a third researcher will re-evaluate the waveforms for the final decision. Evaluators will be strictly blinded to the identity of the specific leads.
Time frame: Periprocedural
The quantitative difference in ST segment amplitude (measured in millimeters or millivolts) will be compared between the mTC2 configuration and the Standard Lead II. Waveform data will be processed using R and RStudio programs to calculate the absolute amplitude differences. A paired t-test will be performed to analyze the statistical agreement and determine if significant differences exist between the two leads.
Time frame: Periprocedural
The quantitative difference in ST segment amplitude (measured in millimeters or millivolts) will be compared between the mSC2 configuration and the Standard Lead II. Waveform data will be processed using R and RStudio programs to calculate the absolute amplitude differences. A paired t-test will be performed to analyze the statistical agreement and determine if significant differences exist between the two leads.
Contact information is provided by the study sponsor or research team.
Dongkyu Lee, MD. Ph.D
CONTACT
Hansu Bae, MD
CONTACT
Hansu Bae
Other
Performance Testing of the Modified Electrocardiogram Lead Placement in Patients Undergoing General Anesthesia
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